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Does It Hurt To Remove Mirena Coil
Atomic theory
I propose a summary of the material using the atomic theory of Prof. Arrigo Amadori
--- 01 - atom.
matter consists of atoms. An atom consists of a core positively electrically charged and a number of electrons, negatively charged, which revolve around.
The core is composed of protons, which are positively charged particles and neutrons particles that are free of charge.
The mass of a proton is approximately equal to the mass of a neutron and both are about 2000 times heavier than an electron. 'S why which are the electrons that revolve around the nucleus (much heavier) and not vice versa. The nucleus is very heavy and "concentrate" while the electrons are very light and mobile.
Normally, the number of electrons that orbit the nucleus equals the number of protons that make up the nucleus. Since that amount of equal value (apart from the sign), an atom is normally electrically neutral . For this reason (and thankfully, otherwise the bodies would be thrown in all directions, since the electric force rather strong) the material is normally electrically neutral.
matter, even if it is thick and "hard", is in fact almost empty. If, by the aspect ratio, consider the size of an apple core, electrons revolve around a distance of approximately one kilometer. This is of extreme importance and, if somehow we could eliminate all this space, we can "shrink" all the mass in a very small space raggiungendodensità enormous. This is what happens to blacks in the holes and neutron stars in which, for example, all the huge mass of a star is compacted into a space of a few cubic miles.
An atom is then composed of a nucleus consisting of nucleons (protons and neutrons) and electrons (in egualnumero protons, when the atom is electrically neutral) that revolve around it. Each atom is indicated by a symbol and two numbers: the atomic number (the number of protons is identical to the number of electrons) and the mass number (the number of nucleons, ie protons and neutrons that make up the nucleus).
The number of neutrons is given, of course, the mass number - atomic number.
Example (helium atom):
An atom can exist in nature with the same number but different atomic mass number. Such atoms are called isotopes and have the same chemical properties (ie, to create compounds, molecules, the same property). An example for this is the hydrogen atom . In nature it is present in the vast majority consists of a proton and an electron that revolves around it. There is, however, in smaller quantities, even the deuterium, which consists of one proton, one neutron and one electron. With it forms heavy water. There is also the tritium (rarer) consists of a proton, two neutrons and an electron. Chemically, hydrogen, deuterium and tritium have the same property (because they have the same number of protons and electrons). In summary:
atoms exist a nature are about 90 listed in a table called the periodic table of elements or table of Mendeleyev:
http://www.apsidium.com/ext_pt/expertab.htm
02 - Chemical bonds
atoms to the left of this table are those metals and have the property of losing electrons to become ions positive. Atoms in the right places, however, are not those metals and have the ability to acquire electrons, ie to become negative ions . The other properties of atoms lose electrons
or buy a less clear-cut. Some atoms may even behave like metals or non-metals as appropriate.
attitude which atoms acquire or lose electrons causes the formation electrical connections between them and that's how molecules are formed , the fundamental constituents of chemical compounds that make up matter.
The simplest type of bond established between the atoms is called ionic bond . It 's the case of table salt, sodium chloride, NaCl. In it, the sodium becomes a positive ion and a chlorine negative ion.
These ions attract each other electrically, and form a regular lattice:
Other types of chemical bonds are based on the fact that electrons are shared by the atoms forming the bond. This is the covalent bond.
It 's very interesting case of' water :
The electrons are shared oxygen atom and two hydrogen atoms so asymmetric.
The electrons from the tents to be more oxygen and therefore the water molecule acts as a electric dipole, or an object with electrical polarity. If
dive, for example, the salt water, the water dipoles break up the lattice of the salt ions inserted between the Na and Cl by ensuring that the salt you melt (while maintaining the link between sodium and chlorine).
If we insert two electrodes in the solution connected to a battery, is the phenomenon of ' electrolysis : ions dissolved in water tend to go, breaking the bonds, to the electrodes with opposite sign.
sodium ions, positive, tend to go towards the negative electrode, the cathode, and chlorine ions, negatives, make to move toward the positive electrode, the anode. This will break the chemical bonds between sodium and chlorine and the electrodes are deposited these atoms (at least theoretically, because in reality things are increasingly complicated, so, in effect, the cathode comprises hydrogen!).
03 - The states of matter.
The matter is in various states ..
If electrical connections between the molecules are strong , the material is presented to the state solid and the molecules are arranged to form a lattice (which may be regular or irregular (amorphous)). The molecules fluctuate around points so fixed geometry without departing significantly from them.
If the electrical connections between the molecules are weaker , it has the liquid. In this state, the bonds are weaker than the solid state, but strong enough to force the liquid (due to gravity) in a container. In this case you do not have a lattice and the molecules have the ability to translate disorderly without abandoning the liquid (if not sporadically (evaporation)).
If the electrical connections between molecules are weak or almost absent, it has the gas. The molecules are free to move and go anywhere in the available space.
04 - atomic models.
In this section we briefly describe the most important atomic models that historically have been proposed. The hypothesis
that matter is composed of atoms goes back to Democritus (400 BC). Atom in greek
means "not divisible." The idea, however, was opposed by atomistic Aristotle, which later became the philosopher "official" church. For this reason we have to wait until as late as 1800 because scientists reconsider the atomic hypothesis. In 1803
Dalton explained the well-known chemical phenomena by which substances are formed from their components according to well-defined relations between integers, assuming that matter was made up of atoms
.
With the discovery of natural radioactivity , it became later that atoms were indivisible particles, they were composed of smaller parts. In 1898
Thomson proposed the first physical model of the atom. He imagined an atom
was made up of a small sphere of positively charged matter (protons and neutrons
had not yet been discovered) in which negative electrons (recently discovered) were immersed.
Rutherford In 1911 he made a crucial experiment to test the model of Thomson.
bombards a thin sheet of gold with alpha rays (helium atoms fully ionized, this private
of electrons). The experiment led to the finding that alpha rays were almost never deviated. They crossed the piece of gold without hardly be disturbed. Only some alpha rays (1%) were diverted from the Gold Leaf and were remarkably (some even were completely rejected).
Based on this fundamental experiment, Rutherford proposed a model of the atom
in which nearly all the mass of the atom is concentrated in a very small portion, called
nucleus (positively charged) and electrons revolve around him as well as
planets revolve around the sun.
The core is so concentrated that the electrons revolve around the distance its huge.
Rutherford's model does have a great "defect" that causes a crisis. According to electromagnetic theory an accelerated charge in motion (not in uniform rectilinear motion)
emits electromagnetic waves and therefore loses energy. For this reason, the electrons of the atom
Rutherford, why rotate on circular orbits, should radiate electromagnetic
and then, losing energy, fall in the nucleus but not
thing that happens because the atoms are very stable objects ( matter appears normally stable). In 1913
Bohr proposed an amendment to the conceptual model of Rutherford. While agreeing
the idea of \u200b\u200b"planetary model", postulates that the electrons were available orbits of "parking" fixed in which they do not emit or absorb energy. An electron emits or absorbs electromagnetic energy in the form of electromagnetic waves only if jumps from one orbit to another .
This idea is not compatible with the laws of classical physics (Newton), is based on the ideas of the emerging quantum mechanics .
The Bohr model explains very well the hydrogen atom but not more complex ones. Sommerfeld then proposed a correction to the Bohr model according to which there was a good match between theory and observations spectra of atoms (a spectrum is the set of frequencies of electromagnetic radiation emitted or absorbed by the electrons of an atom).
Next, we came to an atomic model more consistent with the great progress that
quantum mechanics in the meantime he had done.
In 1930 it was discovered the neutron for which you came soon to a model of almost complete
in which the center is the nucleus composed of protons (positive) and neutrons (protons and neutrons are collectively called nucleons) and revolve around the electrons. The idea of \u200b\u200b
as the electrons orbit the nucleus was deeply amended in the light of the discoveries of quantum mechanics.
was abandoned the notion of orbit and was introduced to the concept of orbital .
According to quantum mechanics an electron not be described in terms of trajectory .
can not therefore say with certainty where an electron is in a certain time or where you will find
in a moment later. You can only know the probability
of finding the electron in a certain point in space.
An orbital is a trajectory in which an electron (according to the ideas of classical physics) can be
, is instead a "cloud " probability where you can find the electron.
Examples of orbitals for the hydrogen atom where more light means more chances of finding the electron (in section):
--- 01 - atom.
matter consists of atoms. An atom consists of a core positively electrically charged and a number of electrons, negatively charged, which revolve around.
The core is composed of protons, which are positively charged particles and neutrons particles that are free of charge.
The mass of a proton is approximately equal to the mass of a neutron and both are about 2000 times heavier than an electron. 'S why which are the electrons that revolve around the nucleus (much heavier) and not vice versa. The nucleus is very heavy and "concentrate" while the electrons are very light and mobile.
Normally, the number of electrons that orbit the nucleus equals the number of protons that make up the nucleus. Since that amount of equal value (apart from the sign), an atom is normally electrically neutral . For this reason (and thankfully, otherwise the bodies would be thrown in all directions, since the electric force rather strong) the material is normally electrically neutral.
matter, even if it is thick and "hard", is in fact almost empty. If, by the aspect ratio, consider the size of an apple core, electrons revolve around a distance of approximately one kilometer. This is of extreme importance and, if somehow we could eliminate all this space, we can "shrink" all the mass in a very small space raggiungendodensità enormous. This is what happens to blacks in the holes and neutron stars in which, for example, all the huge mass of a star is compacted into a space of a few cubic miles.
An atom is then composed of a nucleus consisting of nucleons (protons and neutrons) and electrons (in egualnumero protons, when the atom is electrically neutral) that revolve around it. Each atom is indicated by a symbol and two numbers: the atomic number (the number of protons is identical to the number of electrons) and the mass number (the number of nucleons, ie protons and neutrons that make up the nucleus).
The number of neutrons is given, of course, the mass number - atomic number.
Example (helium atom):
An atom can exist in nature with the same number but different atomic mass number. Such atoms are called isotopes and have the same chemical properties (ie, to create compounds, molecules, the same property). An example for this is the hydrogen atom . In nature it is present in the vast majority consists of a proton and an electron that revolves around it. There is, however, in smaller quantities, even the deuterium, which consists of one proton, one neutron and one electron. With it forms heavy water. There is also the tritium (rarer) consists of a proton, two neutrons and an electron. Chemically, hydrogen, deuterium and tritium have the same property (because they have the same number of protons and electrons). In summary:
atoms exist a nature are about 90 listed in a table called the periodic table of elements or table of Mendeleyev:
http://www.apsidium.com/ext_pt/expertab.htm
02 - Chemical bonds
atoms to the left of this table are those metals and have the property of losing electrons to become ions positive. Atoms in the right places, however, are not those metals and have the ability to acquire electrons, ie to become negative ions . The other properties of atoms lose electrons
or buy a less clear-cut. Some atoms may even behave like metals or non-metals as appropriate.
attitude which atoms acquire or lose electrons causes the formation electrical connections between them and that's how molecules are formed , the fundamental constituents of chemical compounds that make up matter.
The simplest type of bond established between the atoms is called ionic bond . It 's the case of table salt, sodium chloride, NaCl. In it, the sodium becomes a positive ion and a chlorine negative ion.
These ions attract each other electrically, and form a regular lattice:
Other types of chemical bonds are based on the fact that electrons are shared by the atoms forming the bond. This is the covalent bond.
It 's very interesting case of' water :
The electrons are shared oxygen atom and two hydrogen atoms so asymmetric.
The electrons from the tents to be more oxygen and therefore the water molecule acts as a electric dipole, or an object with electrical polarity. If
dive, for example, the salt water, the water dipoles break up the lattice of the salt ions inserted between the Na and Cl by ensuring that the salt you melt (while maintaining the link between sodium and chlorine).
If we insert two electrodes in the solution connected to a battery, is the phenomenon of ' electrolysis : ions dissolved in water tend to go, breaking the bonds, to the electrodes with opposite sign.
sodium ions, positive, tend to go towards the negative electrode, the cathode, and chlorine ions, negatives, make to move toward the positive electrode, the anode. This will break the chemical bonds between sodium and chlorine and the electrodes are deposited these atoms (at least theoretically, because in reality things are increasingly complicated, so, in effect, the cathode comprises hydrogen!).
03 - The states of matter.
The matter is in various states ..
If electrical connections between the molecules are strong , the material is presented to the state solid and the molecules are arranged to form a lattice (which may be regular or irregular (amorphous)). The molecules fluctuate around points so fixed geometry without departing significantly from them.
If the electrical connections between the molecules are weaker , it has the liquid. In this state, the bonds are weaker than the solid state, but strong enough to force the liquid (due to gravity) in a container. In this case you do not have a lattice and the molecules have the ability to translate disorderly without abandoning the liquid (if not sporadically (evaporation)).
If the electrical connections between molecules are weak or almost absent, it has the gas. The molecules are free to move and go anywhere in the available space.
04 - atomic models.
In this section we briefly describe the most important atomic models that historically have been proposed. The hypothesis
that matter is composed of atoms goes back to Democritus (400 BC). Atom in greek
means "not divisible." The idea, however, was opposed by atomistic Aristotle, which later became the philosopher "official" church. For this reason we have to wait until as late as 1800 because scientists reconsider the atomic hypothesis. In 1803
Dalton explained the well-known chemical phenomena by which substances are formed from their components according to well-defined relations between integers, assuming that matter was made up of atoms
.
With the discovery of natural radioactivity , it became later that atoms were indivisible particles, they were composed of smaller parts. In 1898
Thomson proposed the first physical model of the atom. He imagined an atom
was made up of a small sphere of positively charged matter (protons and neutrons
had not yet been discovered) in which negative electrons (recently discovered) were immersed.
Rutherford In 1911 he made a crucial experiment to test the model of Thomson.
bombards a thin sheet of gold with alpha rays (helium atoms fully ionized, this private
of electrons). The experiment led to the finding that alpha rays were almost never deviated. They crossed the piece of gold without hardly be disturbed. Only some alpha rays (1%) were diverted from the Gold Leaf and were remarkably (some even were completely rejected).
Based on this fundamental experiment, Rutherford proposed a model of the atom
in which nearly all the mass of the atom is concentrated in a very small portion, called
nucleus (positively charged) and electrons revolve around him as well as
planets revolve around the sun.
The core is so concentrated that the electrons revolve around the distance its huge.
Rutherford's model does have a great "defect" that causes a crisis. According to electromagnetic theory an accelerated charge in motion (not in uniform rectilinear motion)
emits electromagnetic waves and therefore loses energy. For this reason, the electrons of the atom
Rutherford, why rotate on circular orbits, should radiate electromagnetic
and then, losing energy, fall in the nucleus but not
thing that happens because the atoms are very stable objects ( matter appears normally stable). In 1913
Bohr proposed an amendment to the conceptual model of Rutherford. While agreeing
the idea of \u200b\u200b"planetary model", postulates that the electrons were available orbits of "parking" fixed in which they do not emit or absorb energy. An electron emits or absorbs electromagnetic energy in the form of electromagnetic waves only if jumps from one orbit to another .
This idea is not compatible with the laws of classical physics (Newton), is based on the ideas of the emerging quantum mechanics .
The Bohr model explains very well the hydrogen atom but not more complex ones. Sommerfeld then proposed a correction to the Bohr model according to which there was a good match between theory and observations spectra of atoms (a spectrum is the set of frequencies of electromagnetic radiation emitted or absorbed by the electrons of an atom).
Next, we came to an atomic model more consistent with the great progress that
quantum mechanics in the meantime he had done.
In 1930 it was discovered the neutron for which you came soon to a model of almost complete
in which the center is the nucleus composed of protons (positive) and neutrons (protons and neutrons are collectively called nucleons) and revolve around the electrons. The idea of \u200b\u200b
as the electrons orbit the nucleus was deeply amended in the light of the discoveries of quantum mechanics.
was abandoned the notion of orbit and was introduced to the concept of orbital .
According to quantum mechanics an electron not be described in terms of trajectory .
can not therefore say with certainty where an electron is in a certain time or where you will find
in a moment later. You can only know the probability
of finding the electron in a certain point in space.
An orbital is a trajectory in which an electron (according to the ideas of classical physics) can be
, is instead a "cloud " probability where you can find the electron.
Examples of orbitals for the hydrogen atom where more light means more chances of finding the electron (in section):
Tuesday, June 3, 2008
Ringworm Look Healing
ENRICO FERMI
Daviddi Arianna & Veronica Cappello 4abio1 29 / 05/2008
ENRICO FERMI
Life
Enrico Fermi was born in Rome September 29, 1901. As a child he showed great interest and propensity for mathematics and physics, which came to the contribution of the teacher gazie Amidei. Quest'ultimo lo aiutò seguendo sistematicamente i suoi studi e proponendogli dei test specifici. La sua preparazione proseguì al liceo, ove si diplomò nel 1918, e successivamente presso la scuola normale di Pisa.
Durante gli studi universitari Enrico Fermi si dedicò ad una intensa attività di ricerca sui caratteri distintivi del suono e della diffrazione dei raggi X da parte dei cristalli, conclusosi nello stesso periodol'assegnazione del premio Nobel per la fisica ad Einsteinmise lo studio della struttura atomica al centro dei suoi interessi e lo portò all'elaborazione della statistica antisimmetrica (statistica Fermi-Dirac) basata sul principio di esclusione di Pauli.
La brillante elaborazione lo mise ai vertici degi interessi Corbin, a renowned politician, who gave him the opportunity to create a research group at the Chambers Street Panisperna Portti in Rome and the Italian physics at the highest levels.
Along with a group of young graduates Fermi was able to make the studies that led to the formulation of the mathematical theory of beta decay and the discovery of slow neutrons. An neutron bombardment of this type allowed to obtain activity induced much more 'intense. More information on the subject are summarized in a work done with the collaboration Amaldi "On the absorption and diffusion of slow neutrons, and theoretical work of the same Fermi:" On the motion of neutrons in hydrogenated substances. " The enormous value of the discovery yielded to stop the award of the Nobel Prize for Physics in 1938.
From then until 1942 the world's precarious condition constrinse Fermi to stay in the U.S., were not in force when racial laws adopted in Germany and Italy instead. There he worked the activation of the first nuclear reactor, which was used to produce a development monitored by energy from a fission process, and construction of the atomic bomb.
abandoned his studies in this area dedicated himself, until his death in 1954, the study of subatomic structure and analysis of reactions between Pions and Nucleons. To honor
ilo his enormous contribution to the physics world when subatomic particles were discovered as yet unknown, was given to them in the name of fermions.
The beta decay of the neutrino hypothesis
Substances with radioactive alpha emitting nuclei of helium, for example, radium (Ra) - element discovered by Marie Curie-decays into radon (Rd), a noble gas according to the scheme:
With the alpha radioactivity originating from the atom are ejected two protons and two neutrons, the mass number is reduced then to four units. This phenomenon reflects a structural instability of the heart "father", a phenomenon explained in the early '30s in the context of quantum mechanics. The origin of beta radioactivity, however, had problems at work until Fermi. The beta rays are electrons, but where they come from? Before the discovery of the neutron is believed that the core was composed of protons and electrons. In this context the beta decay would thus be similar to the alpha decay, which is a rearrangement of the components already present in the initial nucleus, a real disintegration. The discovery of the neutron led quickly to abandon that view. The beta radioactivity was an issue even more serious: the electrons are emitted from a single energy but with an energy spectrum that varies continuously. The situation is quite different from that found in the decay of radioactive alpha or gamma, in which the energy of the emitted particle is determined the energy difference between initial and final nucleus, and is therefore always the same for a given type of decay. In the disintegration of radium, for example, alpha particles are emitted with an energy of 4.88 MeV. This simple argument does not work in the case of beta decay, Bohr had come to propose that in this case the energy is not exactly conserved. The solution to this problem was found by Pauli in the beta decay is not only emitted an electron, but also a second particle that escaped their tools. The two are divided particles emitted energy available, it may be in different proportions, so that the energy given the electron is not uniquely determined. The second particle must be neutral, otherwise it would be easily detected through its ionizing power, and could not be a photon, since the experimental data seem to exclude. It must have been an entirely new plot. The hypothesis of this second plot seemed fanciful at the same Pauli. He wrote it only to close colleagues where this particle called the neutron. In the congress held in Rome on nuclear physics with Fermi nel1931 spoke jokingly offered him the appropriate name "neutrino" because its mass must be less than that of the neutron. In 1932, however, still debated for Fermi beta radioactivity in terms of emissions of particles already present in the nucleus; the solution took place in 1933 would have been radically different. In October 1933, the modern point of view on the structure of the nucleus composed of protons and neutrons, which had its official sanction in Brussels at the Solvay Conference. In the discussion that followed the report on nuclear forces Heisenberg, Pauli finally came out into the open with some remarks on the assumptions of the neutrino. The theory of Fermi
The entrance to the neutron by Chadwick in the structure of the electron and nucleus drove out, leaving little place in the presence of a neutrino Pauli. If an electron and a neutrino are not present in A, they must be created in the transition. This was a view hard to accept because it was used think of the electron as a particle material, with its solidity. The ability to create and destroy particles had a precedent in the case of photons. The light is solely made up of photons that are created when light is emitted and absorbed when it is destroyed. An atom can emit a photon from a higher energy level to a lower level. In the reverse process an atom can absorb a photon passing from a lower energy level to a higher level. These processes concerning the photons are described by quantum theory of the electromagnetic field developed by Dirac. In 1927 Jordan and Klein showed that this quantum field theory could be applied to any particle. The electrons that could be seen as particles but also as a wave phenomenon. In quantum physics the concept of particle and the field are fully interchangeable. In any field is a kind of identical particles with each other, but the opposite is true. The language of the field allows you to describe phenomena in which particles are created or destroyed but the work of Fermi on radioactivity beta is the first in which this possibility has been used outside of the theory of photons.
the base of the Fermi theory is the hypothesis that the beta decay of a nucleus is due to a new type of interaction between particles that causes the transmutation of a neutron into a proton with the simultaneous creation of an electron and a neutrino,
.
Since proton and electron have opposite electrical charge while neutrons and neutrinos are electrically neutral, this process has kept the value of the total electric charge. Second stop there was an analogy between this process and the emission of gamma rays at the base,
in which one of the protons in the nucleus changes from a higher to a lower energy state, emitting a photon.
Fermi proposed the existence of a new type of current, now called low-current, which occurs at the transformation of a neutron proton pair leading to the creation of e - v.
In his work of 1933 presented the mathematical structure of his new theory and its application in the study of radioactive beta decay. These can be divided into two classes:
Permits - could take place even if the nucleons (protons, neutrons) were still within the nucleus;
banned - are only made possible by the fact that the nucleons move, they proceed more slowly and their average lifespan is about 100 times longer than the allowed decays. It was only with Fermi
that this phenomenon is explained quantitatively. A second important result of the work is in the determination of the Fermi energy distribution of electrons emitted. Showed that this distribution allows to determine the mass of the neutrino. Fermi's theory contains only one parameter Incognito, G, now called the Fermi constant which can be determined by measuring the average lifespan of an allowed beta decay and determines the intensity of new interactions.
We have said that the transition between neutron and proton in the aforesaid process generates a weak current that leads to the creation of the pair electron - neutrino. The mechanism of this phenomenon is similar to the phenomenon of 'magnetic flux when the current in a circuit generates a magnetic field. In Fermi's theory has a sort of short circuit between the nucleon weak current, activated by the transition from neutron to proton, and a corresponding current of leptons (electron - neutrino), whose activation leads to the creation of the pair electron - neutrino. The weak interaction is then the second stop for a direct interaction between currents, without the action of an intermediate field, such as in the case of magnetic induction.
The stability of the nucleus A nucleus is stable when its mass is less than the sum of the masses of each pair of cores can be obtained from its division. A magnitude that clearly defines the stability of a given species is the atomic binding energy per nucleon or specific, is defined by the following relation
Experience shows that the value of this energy varies little for all species and nuclear is between 7.4 MeV and 8.8 MeV. It's huge energy when you consider that those bond of electrons to their nuclei are only a few electron volts. The binding energy per nucleon is very small for light elements and increases rapidly until it reaches the maximum value for those of average atomic number (at between 40 and 60), then it tends to decrease gradually until it becomes again at least for heavier nuclei. It thus appears that both nuclides lighter and heavier ones are less stable. For the former, consisting of a few protons and neutrons, the effects of the surface of the core are more significant. In fact, the nucleons located near the outer surface of the nucleus are not completely surrounded by other nucleons and are subject to a smaller force of attraction. It follows that in the light elements surface nucleons are relatively larger and therefore heavier than the binding forces are lower. For heavier nuclei instead of the large number of protons leads to increased electrostatic repulsion of their charges to the detriment of the stability of the nuclei themselves.
processes radioactivity
The nuclei of atoms can emit not only heavy particles and electrons as well as gamma radiation: if the issue occurs spontaneously, as occurs in nature for the heavier elements (Z> 80), the process is name of natural radioactivity, in the opposite case we speak of artificial radioactivity. Radioactive decay is the phenomenon by which a nuclide, resulting from the issuance of heavy particles is transformed into a more or less long, in a different nuclide. The transformation can occur through several stages tends, more or less rapidly to a stable form, so, for example, the radioactive series headed by uranium 238 that passes through a succession of decays leading finally to the last item stable consists of the lead. Nuclear fission
The phenomena of radioactivity can be adequately explained by the occurrence of specific nuclear reactions. A nuclear reaction is called when the fission involves the splitting of an unstable nuclide in two or more nuclides with masses comparable with each other.
The study of fission reactions originates from research conducted by Fermi and the boys on the street Panisperna bombardment with neutron beams, produced using the gun to neutrons. The neutrons, having no electric charge, can penetrate inside the nucleus but have little kinetic energy. The odds, therefore, to make nuclear reactions with these particles are greater, especially for the heavier nuclei that have a lower binding energy. We need, however, neutron sources and those rich enough, already in the thirties, were available to physicists working in this field of scientific research. During the experiments
carried out by Fermi and his collaborators was noticed by bombarding uranium with slow neutrons, was obtained by the formation of several radioactive nuclides. It was thought however that these elements have an atomic number close to that of uranium, and because there were recognized as among the known nuclear species, it is proposed that this was transuranic elements.
But in 1939 the German physicists O. Hahn and F. Strassmann proved that when the uranium was bombarded with neutrons to promote the formation of two large nuclear fragments which subsequently suffered a series of radioactive transformations, among them the reaction products identified the nuclei of barium and krypton. In this type of nuclear reaction, which consists in the splitting of atomic nuclei of heavier elements into two (rarely more than two) with masses that are in a ratio of the order of 3 / 2, was given the name of nuclear fission. According to the model nuclear drop, designed by N. Bohr, the fission reaction can be interpreted as follows. When a heavy nucleus, for example, captures a neutron, into a state of instability and stands to vibrate. Subsequently, it tends to stretch in one direction and narrows in the middle to break up into two.
Following the first experiments we could prove that the fission with neutrons also occurred in the thorium and protactinium. But while these elements was necessary for high kinetic energy of neutrons used for uranium, however, the reaction took place with both fast neutrons and slow neutrons. Instead, he was able to prove that, while the most abundant isotope of uranium (99,274%), which were needed fast neutrons, for the least abundant (0.71%), ie the 'slow or thermal neutrons were sufficient, the latter designation means that these neutrons have a kinetic energy of the order of magnitude as that caused by thermal agitation of molecules. Another remarkable fact, which was to manifest because of the use of atomic energy, was that in the fission of uranium 235 were issued at least two or three neutrons per nucleus that underwent disintegration.
In the fission process when discovering the convenience of slow neutrons by passing them through or within a block of paraffin or a water tank (the famous fish pond via Panisperna), the bombing more interesting, and initially very mysterious, will be noted that the uranium. The isotope of uranium was able to separate uranium 235 and the reaction against it can be schematized as follows: X and Y are nuclides with mass numbers around 127, the number of neutrons ( n) varies depending on the actually produced nuclides, the energy released is about 200 MeV for the nucleus of uranium nucleus that is broken. The amount of energy produced is enormous, considering that the combustion of a carbon atom free about 4 eV, while the splitting of a uranium nucleus involves the release of an amount of energy 50 million times. This happens because the nuclear reactions have significant changes in mass but that no chemical reactions occurring in the normal combustion. Returning to the reaction described, it should be noted that the production of neutrons can be absorbed by neighboring nuclei of uranium fission giving rise to new processes and new power generation, the first neutron that produced the initial cleavage triggers a chain reaction so that in short time includes the entire amount of uranium available. The first practical use the fission reaction was the appalling destruction of Hiroshima and Nagasaki, which marked the end of World War II. In the reaction becomes explosive atomic bomb because they are rapidly brought into contact two masses "subcritical" so that the system, on balance, exceed the mass critical. The critical mass is the smallest amount of material needed to fissibile self-sustaining chain reaction. In the nuclear chain reaction is controlled and adjusted using rods of cadmium or graphite or boron steel that have the ability to easily capture neutrons. In the reactor involved in these functions the control rods. An adjustment of the reactor is ensured even the water that cools the core, turns into steam as a result: it absorbs, slowing down, a certain amount of neutrons. The steam produced is sent to the turbine, coupled to the alternator is capable of generating electricity.
Fermions
look at the structure of atoms is possible to ask a question: we know that the particles that make up the core affected by the strong interaction, we know that the electrons circling the nucleus like the moon around the earth, but because the electron is not affected by the strong nuclear force much more intense than that in the mail when its motion is very close to the nucleus? This question Fermi in collaboration with the physicist Dirac, tried to answer by introducing the concept of fermion. The class includes
fermions leptons, which have lower mass than the proton, and baryons, with mass equal to or greater than the proton.
stable particles are the photon, the particle of light and "quantum" of energy and leptons, which are the lightest elementary particles with the exception of the muon. The leptons include the electron, the muon (most stable), which equal to the electron mass and electric charge, positive or negative, and the neutrino, whose mass is practically zero and is issued in radioazione beta along with a positron, the m particle, the particle you their antiparticles.
The following are the baryons that comprise the proton (stable), the neutron (the semi), which has an average life of 1.01 • 10 s. ³, the fibulae, most resonances in rapid decline.
The fibulae are particles with mass from 2100 to 2600 times higher than that of electrons, and decay when they give rise to protons, neutrons and mesons. Fermi said, and his statements are considered valid today, that in reality only a few particles are affected by the strong nuclear force, as only the electrically charged particles are affected by the electromagnetic interaction.
We can therefore make a distinction between particles that are affected by strong interactions and those that are not affected: the former are called hadrons seconds are the leptons.
Fermions:
A fermion is any particle whose intrinsic angular momentum (spin) has a value odd multiple of half (1 / 2, 3 / 2 ,...), measured in units of h (h-cut ). As a result of their angular momentum, all the fermions obey the Pauli exclusion principle.
The fundamental matter particles (quarks and leptons) as well as most of the composite particles (like protons and neutrons) are fermions. Therefore, according to the Pauli exclusion principle, these particles can not coexist in the same place. And that, for materials under ordinary conditions, is an important property. 
Daviddi Arianna & Veronica Cappello 4abio1 29 / 05/2008
ENRICO FERMI
Life
Enrico Fermi was born in Rome September 29, 1901. As a child he showed great interest and propensity for mathematics and physics, which came to the contribution of the teacher gazie Amidei. Quest'ultimo lo aiutò seguendo sistematicamente i suoi studi e proponendogli dei test specifici. La sua preparazione proseguì al liceo, ove si diplomò nel 1918, e successivamente presso la scuola normale di Pisa.
Durante gli studi universitari Enrico Fermi si dedicò ad una intensa attività di ricerca sui caratteri distintivi del suono e della diffrazione dei raggi X da parte dei cristalli, conclusosi nello stesso periodol'assegnazione del premio Nobel per la fisica ad Einsteinmise lo studio della struttura atomica al centro dei suoi interessi e lo portò all'elaborazione della statistica antisimmetrica (statistica Fermi-Dirac) basata sul principio di esclusione di Pauli.
La brillante elaborazione lo mise ai vertici degi interessi Corbin, a renowned politician, who gave him the opportunity to create a research group at the Chambers Street Panisperna Portti in Rome and the Italian physics at the highest levels.
Along with a group of young graduates Fermi was able to make the studies that led to the formulation of the mathematical theory of beta decay and the discovery of slow neutrons. An neutron bombardment of this type allowed to obtain activity induced much more 'intense. More information on the subject are summarized in a work done with the collaboration Amaldi "On the absorption and diffusion of slow neutrons, and theoretical work of the same Fermi:" On the motion of neutrons in hydrogenated substances. " The enormous value of the discovery yielded to stop the award of the Nobel Prize for Physics in 1938.
From then until 1942 the world's precarious condition constrinse Fermi to stay in the U.S., were not in force when racial laws adopted in Germany and Italy instead. There he worked the activation of the first nuclear reactor, which was used to produce a development monitored by energy from a fission process, and construction of the atomic bomb.
abandoned his studies in this area dedicated himself, until his death in 1954, the study of subatomic structure and analysis of reactions between Pions and Nucleons. To honor
ilo his enormous contribution to the physics world when subatomic particles were discovered as yet unknown, was given to them in the name of fermions.
The beta decay of the neutrino hypothesis
Substances with radioactive alpha emitting nuclei of helium, for example, radium (Ra) - element discovered by Marie Curie-decays into radon (Rd), a noble gas according to the scheme:
With the alpha radioactivity originating from the atom are ejected two protons and two neutrons, the mass number is reduced then to four units. This phenomenon reflects a structural instability of the heart "father", a phenomenon explained in the early '30s in the context of quantum mechanics. The origin of beta radioactivity, however, had problems at work until Fermi. The beta rays are electrons, but where they come from? Before the discovery of the neutron is believed that the core was composed of protons and electrons. In this context the beta decay would thus be similar to the alpha decay, which is a rearrangement of the components already present in the initial nucleus, a real disintegration. The discovery of the neutron led quickly to abandon that view. The beta radioactivity was an issue even more serious: the electrons are emitted from a single energy but with an energy spectrum that varies continuously. The situation is quite different from that found in the decay of radioactive alpha or gamma, in which the energy of the emitted particle is determined the energy difference between initial and final nucleus, and is therefore always the same for a given type of decay. In the disintegration of radium, for example, alpha particles are emitted with an energy of 4.88 MeV. This simple argument does not work in the case of beta decay, Bohr had come to propose that in this case the energy is not exactly conserved. The solution to this problem was found by Pauli in the beta decay is not only emitted an electron, but also a second particle that escaped their tools. The two are divided particles emitted energy available, it may be in different proportions, so that the energy given the electron is not uniquely determined. The second particle must be neutral, otherwise it would be easily detected through its ionizing power, and could not be a photon, since the experimental data seem to exclude. It must have been an entirely new plot. The hypothesis of this second plot seemed fanciful at the same Pauli. He wrote it only to close colleagues where this particle called the neutron. In the congress held in Rome on nuclear physics with Fermi nel1931 spoke jokingly offered him the appropriate name "neutrino" because its mass must be less than that of the neutron. In 1932, however, still debated for Fermi beta radioactivity in terms of emissions of particles already present in the nucleus; the solution took place in 1933 would have been radically different. In October 1933, the modern point of view on the structure of the nucleus composed of protons and neutrons, which had its official sanction in Brussels at the Solvay Conference. In the discussion that followed the report on nuclear forces Heisenberg, Pauli finally came out into the open with some remarks on the assumptions of the neutrino. The theory of Fermi
The entrance to the neutron by Chadwick in the structure of the electron and nucleus drove out, leaving little place in the presence of a neutrino Pauli. If an electron and a neutrino are not present in A, they must be created in the transition. This was a view hard to accept because it was used think of the electron as a particle material, with its solidity. The ability to create and destroy particles had a precedent in the case of photons. The light is solely made up of photons that are created when light is emitted and absorbed when it is destroyed. An atom can emit a photon from a higher energy level to a lower level. In the reverse process an atom can absorb a photon passing from a lower energy level to a higher level. These processes concerning the photons are described by quantum theory of the electromagnetic field developed by Dirac. In 1927 Jordan and Klein showed that this quantum field theory could be applied to any particle. The electrons that could be seen as particles but also as a wave phenomenon. In quantum physics the concept of particle and the field are fully interchangeable. In any field is a kind of identical particles with each other, but the opposite is true. The language of the field allows you to describe phenomena in which particles are created or destroyed but the work of Fermi on radioactivity beta is the first in which this possibility has been used outside of the theory of photons.
the base of the Fermi theory is the hypothesis that the beta decay of a nucleus is due to a new type of interaction between particles that causes the transmutation of a neutron into a proton with the simultaneous creation of an electron and a neutrino,
.
Since proton and electron have opposite electrical charge while neutrons and neutrinos are electrically neutral, this process has kept the value of the total electric charge. Second stop there was an analogy between this process and the emission of gamma rays at the base,
in which one of the protons in the nucleus changes from a higher to a lower energy state, emitting a photon.
Fermi proposed the existence of a new type of current, now called low-current, which occurs at the transformation of a neutron proton pair leading to the creation of e - v.
In his work of 1933 presented the mathematical structure of his new theory and its application in the study of radioactive beta decay. These can be divided into two classes:
Permits - could take place even if the nucleons (protons, neutrons) were still within the nucleus;
banned - are only made possible by the fact that the nucleons move, they proceed more slowly and their average lifespan is about 100 times longer than the allowed decays. It was only with Fermi
that this phenomenon is explained quantitatively. A second important result of the work is in the determination of the Fermi energy distribution of electrons emitted. Showed that this distribution allows to determine the mass of the neutrino. Fermi's theory contains only one parameter Incognito, G, now called the Fermi constant which can be determined by measuring the average lifespan of an allowed beta decay and determines the intensity of new interactions.
We have said that the transition between neutron and proton in the aforesaid process generates a weak current that leads to the creation of the pair electron - neutrino. The mechanism of this phenomenon is similar to the phenomenon of 'magnetic flux when the current in a circuit generates a magnetic field. In Fermi's theory has a sort of short circuit between the nucleon weak current, activated by the transition from neutron to proton, and a corresponding current of leptons (electron - neutrino), whose activation leads to the creation of the pair electron - neutrino. The weak interaction is then the second stop for a direct interaction between currents, without the action of an intermediate field, such as in the case of magnetic induction.
The stability of the nucleus A nucleus is stable when its mass is less than the sum of the masses of each pair of cores can be obtained from its division. A magnitude that clearly defines the stability of a given species is the atomic binding energy per nucleon or specific, is defined by the following relation
Experience shows that the value of this energy varies little for all species and nuclear is between 7.4 MeV and 8.8 MeV. It's huge energy when you consider that those bond of electrons to their nuclei are only a few electron volts. The binding energy per nucleon is very small for light elements and increases rapidly until it reaches the maximum value for those of average atomic number (at between 40 and 60), then it tends to decrease gradually until it becomes again at least for heavier nuclei. It thus appears that both nuclides lighter and heavier ones are less stable. For the former, consisting of a few protons and neutrons, the effects of the surface of the core are more significant. In fact, the nucleons located near the outer surface of the nucleus are not completely surrounded by other nucleons and are subject to a smaller force of attraction. It follows that in the light elements surface nucleons are relatively larger and therefore heavier than the binding forces are lower. For heavier nuclei instead of the large number of protons leads to increased electrostatic repulsion of their charges to the detriment of the stability of the nuclei themselves.
processes radioactivity
The nuclei of atoms can emit not only heavy particles and electrons as well as gamma radiation: if the issue occurs spontaneously, as occurs in nature for the heavier elements (Z> 80), the process is name of natural radioactivity, in the opposite case we speak of artificial radioactivity. Radioactive decay is the phenomenon by which a nuclide, resulting from the issuance of heavy particles is transformed into a more or less long, in a different nuclide. The transformation can occur through several stages tends, more or less rapidly to a stable form, so, for example, the radioactive series headed by uranium 238 that passes through a succession of decays leading finally to the last item stable consists of the lead. Nuclear fission
The phenomena of radioactivity can be adequately explained by the occurrence of specific nuclear reactions. A nuclear reaction is called when the fission involves the splitting of an unstable nuclide in two or more nuclides with masses comparable with each other.
The study of fission reactions originates from research conducted by Fermi and the boys on the street Panisperna bombardment with neutron beams, produced using the gun to neutrons. The neutrons, having no electric charge, can penetrate inside the nucleus but have little kinetic energy. The odds, therefore, to make nuclear reactions with these particles are greater, especially for the heavier nuclei that have a lower binding energy. We need, however, neutron sources and those rich enough, already in the thirties, were available to physicists working in this field of scientific research. During the experiments
carried out by Fermi and his collaborators was noticed by bombarding uranium with slow neutrons, was obtained by the formation of several radioactive nuclides. It was thought however that these elements have an atomic number close to that of uranium, and because there were recognized as among the known nuclear species, it is proposed that this was transuranic elements.
But in 1939 the German physicists O. Hahn and F. Strassmann proved that when the uranium was bombarded with neutrons to promote the formation of two large nuclear fragments which subsequently suffered a series of radioactive transformations, among them the reaction products identified the nuclei of barium and krypton. In this type of nuclear reaction, which consists in the splitting of atomic nuclei of heavier elements into two (rarely more than two) with masses that are in a ratio of the order of 3 / 2, was given the name of nuclear fission. According to the model nuclear drop, designed by N. Bohr, the fission reaction can be interpreted as follows. When a heavy nucleus, for example, captures a neutron, into a state of instability and stands to vibrate. Subsequently, it tends to stretch in one direction and narrows in the middle to break up into two.
Following the first experiments we could prove that the fission with neutrons also occurred in the thorium and protactinium. But while these elements was necessary for high kinetic energy of neutrons used for uranium, however, the reaction took place with both fast neutrons and slow neutrons. Instead, he was able to prove that, while the most abundant isotope of uranium (99,274%), which were needed fast neutrons, for the least abundant (0.71%), ie the 'slow or thermal neutrons were sufficient, the latter designation means that these neutrons have a kinetic energy of the order of magnitude as that caused by thermal agitation of molecules. Another remarkable fact, which was to manifest because of the use of atomic energy, was that in the fission of uranium 235 were issued at least two or three neutrons per nucleus that underwent disintegration.
In the fission process when discovering the convenience of slow neutrons by passing them through or within a block of paraffin or a water tank (the famous fish pond via Panisperna), the bombing more interesting, and initially very mysterious, will be noted that the uranium. The isotope of uranium was able to separate uranium 235 and the reaction against it can be schematized as follows: X and Y are nuclides with mass numbers around 127, the number of neutrons ( n) varies depending on the actually produced nuclides, the energy released is about 200 MeV for the nucleus of uranium nucleus that is broken. The amount of energy produced is enormous, considering that the combustion of a carbon atom free about 4 eV, while the splitting of a uranium nucleus involves the release of an amount of energy 50 million times. This happens because the nuclear reactions have significant changes in mass but that no chemical reactions occurring in the normal combustion. Returning to the reaction described, it should be noted that the production of neutrons can be absorbed by neighboring nuclei of uranium fission giving rise to new processes and new power generation, the first neutron that produced the initial cleavage triggers a chain reaction so that in short time includes the entire amount of uranium available. The first practical use the fission reaction was the appalling destruction of Hiroshima and Nagasaki, which marked the end of World War II. In the reaction becomes explosive atomic bomb because they are rapidly brought into contact two masses "subcritical" so that the system, on balance, exceed the mass critical. The critical mass is the smallest amount of material needed to fissibile self-sustaining chain reaction. In the nuclear chain reaction is controlled and adjusted using rods of cadmium or graphite or boron steel that have the ability to easily capture neutrons. In the reactor involved in these functions the control rods. An adjustment of the reactor is ensured even the water that cools the core, turns into steam as a result: it absorbs, slowing down, a certain amount of neutrons. The steam produced is sent to the turbine, coupled to the alternator is capable of generating electricity.
Fermions
look at the structure of atoms is possible to ask a question: we know that the particles that make up the core affected by the strong interaction, we know that the electrons circling the nucleus like the moon around the earth, but because the electron is not affected by the strong nuclear force much more intense than that in the mail when its motion is very close to the nucleus? This question Fermi in collaboration with the physicist Dirac, tried to answer by introducing the concept of fermion. The class includes
fermions leptons, which have lower mass than the proton, and baryons, with mass equal to or greater than the proton.
stable particles are the photon, the particle of light and "quantum" of energy and leptons, which are the lightest elementary particles with the exception of the muon. The leptons include the electron, the muon (most stable), which equal to the electron mass and electric charge, positive or negative, and the neutrino, whose mass is practically zero and is issued in radioazione beta along with a positron, the m particle, the particle you their antiparticles.
The following are the baryons that comprise the proton (stable), the neutron (the semi), which has an average life of 1.01 • 10 s. ³, the fibulae, most resonances in rapid decline.
The fibulae are particles with mass from 2100 to 2600 times higher than that of electrons, and decay when they give rise to protons, neutrons and mesons. Fermi said, and his statements are considered valid today, that in reality only a few particles are affected by the strong nuclear force, as only the electrically charged particles are affected by the electromagnetic interaction.
We can therefore make a distinction between particles that are affected by strong interactions and those that are not affected: the former are called hadrons seconds are the leptons.
Fermions:
A fermion is any particle whose intrinsic angular momentum (spin) has a value odd multiple of half (1 / 2, 3 / 2 ,...), measured in units of h (h-cut ). As a result of their angular momentum, all the fermions obey the Pauli exclusion principle.
The fundamental matter particles (quarks and leptons) as well as most of the composite particles (like protons and neutrons) are fermions. Therefore, according to the Pauli exclusion principle, these particles can not coexist in the same place. And that, for materials under ordinary conditions, is an important property.
Average Annual Rainfall In Egypt
the case nikola tesla
In scientific history of the Tunguska event was brought in and a great character, the man who invented the electric light, which built the first hydroelectric power station in the world, who invented the radio and many other interesting things.
It was also the discoverer of fluorescent lighting, and a network of seismology data communications worldwide. Nikola Tesla, a scientist who is without a doubt the unknown hero of the science of the twentieth century. His life was an incredible series of scientific triumphs, followed by an equally inconceivable series of personal disasters trade.
Smiljan was born in Lika, in the Croatia, in 1856. After the first studies to Lika and Carlstadt under the influence of his mother Georgina Mandic, also invented, as the father on the other hand, Tesla moved to the University of Graz, where he studied mathematics and physics, graduating in 1877. He had then the desire to study philosophy in Prague. Proposed in 1881 in Budapest his first invention: the telephone repeater. In 1884 he emigrated to the United States. After a period in which he collaborated with TA Edison in his laboratory in Menlo Park, left him after a quarrel. Then worked for G. Westinghouse who had recently founded the Westinghouse Electrical Company. He preferred, however, after a short time, work for himself developing a whole series of important inventions. A general characteristic of many of these had the confidence that Tesla had for alternating currents, in contrast to what was initially thought Edison. The proof of the superiority of these currents placed it in place in 1893, illuminating the whole world exposition in Chicago. Anticipated at least two years of wireless telegraphy, but without developing it. The system of alternating currents, Tesla was also chosen by the project of energy use, assigned to Westinghouse, of Niagara Falls.
The many inventions have made him one of the most prolific and the inventors of the nineteenth and twentieth century. His creative abilities were extraordinary as well as the technical skill was remarkable. He was the only defect of not being able to literally create and deepen its many ideas. Those who knew how to accomplish today is astonishing. But any chance to celebrate achievements in life was lost in the confusion created by his death in New York January 7, 1943, in time of war. All his work was declared "top secret" by the FBI, the U.S. Navy and Vice President Wallace. He he wrote: "I have always a sense of deep satisfaction and inexplicable to learn that my polyphase system is used around the world to illuminate the darker moments of life, to improve quality of life, and that my wireless system, in all its essential characteristics, is used to render a service and to give happiness to people all over the world. "
It was a brilliant scientist, a prophet who actually reads in the future, but that his time was not able to understand. The end result was that one of the greatest benefactors of humanity has been forgotten. Tesla died as he lived: alone and anonymously, intended for oblivion 'top secret order that prohibited to talk about his work.
What may have caused this? The break with Edison Tesla led to abandon the traditional conception of electricity. He moved to Colorado Springs, near Denver, trying to build a new electricity concept: communicate anywhere in the world using the wires. According to his theory, the earth itself was a natural conductor and could be exploited in order to have the electrical waves sent from a central transmitter. These waves were collected by receivers anywhere in the world.
Since no one wanted to believe, in 1899, Tesla built a transmitter that could also act as a receiver. With this structure, placed on his laboratory, hoping to send stray electric wave to take it up. Realizing that a single wave would lose power in the transfer, thought to provide Subsequent electrical impulses, thus creating a continuum of increasing power energy package. A Colorado Springs all the inhabitants could see the huge and strange antenna, 60 meters high, ending with a ball of iron. Many were witnesses who saw lit 200 lamps without wires connecting to 40 miles away. An experiment with particular quell'antenna remain in the history of this civilization: a lightning came from the globe of iron at the top antenna, grew in size to become a world power that sent him to the sky lightning crackling at least 50 meters in length. The area was filled with the rumble of thunder and the grass took on a bright green color as if there was phosphorescence. The fact was certainly more traumatic than that borne by the inhabitants, who, walking in the streets, saw electric sparks that shoot out from their feet on the pavement ended. After such a show even the financier JP Morgan, believes the inventive genius of Tesla, well-invested $ 150,000 in the project of the transmission of energy. So Nikola Tesla moved to New York and began the construction of the first communications tower in Long Island: the Wardenclyffe. That was in 1900.
Wardenclyffe The imposing tower, built by Tesla on Long Island.
Three years later, when the Wardenclyffe was completed, Tesla announced another of his discoveries: would have been enough to give a powerful energy to their transmitters to transform the Earth's lithosphere in a giant holder. It was enough to put into practice a metal stick into the ground, connected to a transformer to get electricity at will. Tesla was of the opinion that to generate the initial energy was sufficient to use hydropower. The weakness of such invention was that if the transmitter had sent, instead of around the globe uniformly, a large amount of energy in one place, then it would been a total destruction. According to calculations, this system could easily send an energy equal to a 10-megaton nuclear bomb. The History reminds us that Tesla never had the chance to experience its revolutionary invention. In 1903, Morgan withdrew his financial supporter. Surely this American tycoon has pointed out that a radius of 10 megatons of death could also be good, but to provide electricity in an unlimited and free to the whole world was unthinkable. At that point, Tesla was abandoned by all. Heavily in debt, had to sell off the Colorado Springs lab for a few dollars, so that in 1906 no longer had money to pay employees' wages Wardenclyffe, which remained empty. It was at this time that Tesla's life began to be clothed in mystery.
When the world began the race arms, which then will lead to World War I, Tesla tried to bring water to his "mill" offering a system of destruction more powerful. It is believed however that they were only rumors, supported by an unusual event such as the disappearance of Jena the French ship which blew up under mysterious circumstances. It is known that Tesla was neutral before quest'esecrabile gesture. He had stated previously, that his transmitter could have sent "shock waves" of such intensity as to cause an explosion in santabarbara a warship and blow it apart. The fact that the Wardenclyffe, without operators, would work without problems meant that there were state, then speculate on its use in the case of Tunguska. In practice
in 1908 Tesla seems to have said: "Mine is not a dream. You can create a wireless system that can make any area of \u200b\u200bthe Earth uninhabitable, without exposing the population of other parts to serious damage or have adverse incidents .
There is much uncertainty, considering that Tesla, in a desperate attempt to get financial aid for his research, he has to let go of quite specific statements.
is known, however, that until 1915 Tesla did not have any funding that could help him, so that the Wardenclyffe was razed in 1917. A strange thing is that he had the habit July 10 of each year on his birthday, to make sensational revelations about the future of electricity. Statements were so dramatic that the rite ended up being ridiculous.
In 1935 he tried to engage again in a mogul Morgan defense project that uses laser beams of particles similar to those we know today through the film of "Star Trek".
When Tesla died, his inventions were requisitioned by the U.S. government and, much later, returned to his nephew, except on death ray.
The fact that Tesla might have actually triggered the Wardenclyffe Tower to determine the devastation of the Tunguska event remains a conjecture that some authors does not take account of some very important facts. Nevertheless, I repeat, that Tesla was not in a position to potentially make a similar experience. One of the technical facts that he had to overcome was the availability of primary energy to power up to 30 megatons end. It was not possible, then perform a similar experiment in secret and above the hydroelectric plant in question could not be absolutely one. An experiment of this kind to those who could he do? Perhaps the U.S. government? Another inconsistency is found in the likely trajectory suggested that the fireball energy should have made.
Alleged trajectory of the fireball that would have struck the Tunguska with the energy generated by Wardenclyffe Tower, designed by the brilliant idea of \u200b\u200bNikola Tesla.
analyzing the geometric aspect, it must have come from the north and curvilinear features to hit the uninhabited area of \u200b\u200bthe Tunguska: the opposite of what the witnesses reported the majority of the time.
I also think that, by failing to present tangible evidence yet of a real trial to that effect, it is quite difficult to determine whether the effects can be compared with actual measurements found in the taiga, with all the peculiarities of the event, including explosion, in terms have already been analyzed.
One thing is certain, however: the invention of Nikola Tesla, conosciuta come la trasmissione d’energia elettrica senza fili, verrà in seguito applicata ma non per scopi benefici. Tesla in proposito lasciò scritto: "Il successo pratico di un’idea, indipendentemente dalle sue qualità inerenti, dipende dalla scelta dei contemporanei. Se è al passo coi tempi, essa viene rapidamente adottata; in caso contrario, è destinata a vivere come un germoglio che sboccia, attirato dalle lusinghe e dal calore del primo sole, per essere poi danneggiato e crescere con difficoltà a causa del gelo che s’impone."
Questo gelo è stato recentemente sciolto, purtroppo. Nell’evoluzione tecnologica militare degli Stati Uniti da qualche anno è comparso il progetto HAARP (High Frequency Active Auroral Research Project). The Pentagon is making us believe that this is a harmless experiment, as we are dealing with a weapon that acts on the ionosphere with indescribable likely developments for living beings. In 1987, the adviser of the Atlantic Richfield Corporation (ARCO), physicist Bernard J. Eastlund, he applied all his intellectual resources to resume the patent of Nikola Tesla Wardenclyffe. The new system was called "Method and apparatus for altering a region of the atmosphere, ionosphere and / or magnetosphere. Indeed, the method was used to Eastlund to discover large deposits of natural gas that the oil company ARCO was looking for in Alaska. When
studies had achieved some success, interrupted the nuclear physicist Edward Teller (one of the staunchest U.S. scientists, which is devoted to building an atomic bomb, and especially of the hydrogen), which gave rise to new initiatives secret, which could to continue the military system of "Star War". In a short time Alaska became the last frontier of military research.
The mammoth and several antennas located in Gakona (Alaska), part of the HAARP Project.
The main installation of the Project HAARP in Alaska is located in Gakona, about 150 miles northeast of Anchorage. The choice This site was made for three basic reasons:
• Its proximity to the Pole and then to the zone of concentration of the magnetic lines of our planet.
• The presence of remarkable natural energy sources in the subsurface.
• Its distance from urban centers.
The HAARP program led to the construction of a system of 360 antennas, 23 meters high, capable of transmitting, with the aim to improve military communications, a "beam" of high frequency energy in the ionosphere. The ionosphere is the part of atmospheric region that begins about 50 km above sea level and ends around 800 km According to the latest rumors, this weapon would be capable interfering with extensive areas of the atmosphere and thus, according to military logic, missiles and shoot down airplanes and anything else.
There are more than 400 patents related to HAARP project and the majority of these projects are offensive or better are offensive weapons. There is always the logic that the system uses the radiation beam of energy directly from the earth into space. You can carry the high frequency energy in an area where a receiving antenna has been installed, but can radiate as well as military areas, even in urban centers. Of course not escaped the military high command to use a similar technology to reduce flying objects of Origin extraterrestrial, if this is of course possible. Pure Soviet scientists have devoted themselves to such research for over 25 years, until the political change and the dismantling of the USSR led to a dramatic weakening economy, with consequent deprivation of the necessary financial support to institutions of investigation.
Headquartered in Gakona, there are other similar installations, located in various parts of the planet. The first can be located in Arecibo (Puerto Rico), the second to Alaska in Fairbanks, the third in Tromso (Norway), then to Pine Bush Steeplebush in Australia and finally to England. Surely you are building other facilities of its kind in the southern hemisphere of the planet.
It was learned that the pilot plant of Gakona you are able to broadcast to 1.7 billion watts into the atmosphere. This is actually the negative development of the invention of Tesla. He hated the war and in this regard, he said: "We can abolish war by outlawing. There may be terminated by disarming the strong. But you can stop making all countries able to defend themselves. I just found a new weapon of defense which, if adopted, will completely transform the relations between nations. make them all, big and small they are, invulnerable to any attack from land, sea or air. We must, first, build a great workshop for the manufacture of this weapon, but when it is completed, you can destroy people and machines within a radius of 320 km "
In 1934, Tesla described in an article similar to the laser equipment, saying:" This instrument projects particles which may be relatively large or microscopic, that are used to transfer energy at a great distance a million times stronger than that achievable with any other range. So a stream thinner than a strand can transmit thousands of horsepower. And nothing can resist. "
Because of his statements, it was rumored that Tesla had invented a" death ray. "He immediately replied:" The invention I mentioned, on several occasions, he has nothing to do with what is commonly called the 'death ray'. "
Let me conclude on Nikola Tesla, one of the most brilliant men appeared on this planet, with its symbolic phrase that describes its nature as a scientist in a superlative: "The Gift of the force of reason comes from God, from being the Divine, and if you concentrate our minds on that truth, we establish harmony with this great force. My mother taught me to seek all truth in the Bible. - Nikola Tesla ". 
In scientific history of the Tunguska event was brought in and a great character, the man who invented the electric light, which built the first hydroelectric power station in the world, who invented the radio and many other interesting things.
It was also the discoverer of fluorescent lighting, and a network of seismology data communications worldwide. Nikola Tesla, a scientist who is without a doubt the unknown hero of the science of the twentieth century. His life was an incredible series of scientific triumphs, followed by an equally inconceivable series of personal disasters trade.
Smiljan was born in Lika, in the Croatia, in 1856. After the first studies to Lika and Carlstadt under the influence of his mother Georgina Mandic, also invented, as the father on the other hand, Tesla moved to the University of Graz, where he studied mathematics and physics, graduating in 1877. He had then the desire to study philosophy in Prague. Proposed in 1881 in Budapest his first invention: the telephone repeater. In 1884 he emigrated to the United States. After a period in which he collaborated with TA Edison in his laboratory in Menlo Park, left him after a quarrel. Then worked for G. Westinghouse who had recently founded the Westinghouse Electrical Company. He preferred, however, after a short time, work for himself developing a whole series of important inventions. A general characteristic of many of these had the confidence that Tesla had for alternating currents, in contrast to what was initially thought Edison. The proof of the superiority of these currents placed it in place in 1893, illuminating the whole world exposition in Chicago. Anticipated at least two years of wireless telegraphy, but without developing it. The system of alternating currents, Tesla was also chosen by the project of energy use, assigned to Westinghouse, of Niagara Falls.
The many inventions have made him one of the most prolific and the inventors of the nineteenth and twentieth century. His creative abilities were extraordinary as well as the technical skill was remarkable. He was the only defect of not being able to literally create and deepen its many ideas. Those who knew how to accomplish today is astonishing. But any chance to celebrate achievements in life was lost in the confusion created by his death in New York January 7, 1943, in time of war. All his work was declared "top secret" by the FBI, the U.S. Navy and Vice President Wallace. He he wrote: "I have always a sense of deep satisfaction and inexplicable to learn that my polyphase system is used around the world to illuminate the darker moments of life, to improve quality of life, and that my wireless system, in all its essential characteristics, is used to render a service and to give happiness to people all over the world. "
It was a brilliant scientist, a prophet who actually reads in the future, but that his time was not able to understand. The end result was that one of the greatest benefactors of humanity has been forgotten. Tesla died as he lived: alone and anonymously, intended for oblivion 'top secret order that prohibited to talk about his work.
What may have caused this? The break with Edison Tesla led to abandon the traditional conception of electricity. He moved to Colorado Springs, near Denver, trying to build a new electricity concept: communicate anywhere in the world using the wires. According to his theory, the earth itself was a natural conductor and could be exploited in order to have the electrical waves sent from a central transmitter. These waves were collected by receivers anywhere in the world.
Since no one wanted to believe, in 1899, Tesla built a transmitter that could also act as a receiver. With this structure, placed on his laboratory, hoping to send stray electric wave to take it up. Realizing that a single wave would lose power in the transfer, thought to provide Subsequent electrical impulses, thus creating a continuum of increasing power energy package. A Colorado Springs all the inhabitants could see the huge and strange antenna, 60 meters high, ending with a ball of iron. Many were witnesses who saw lit 200 lamps without wires connecting to 40 miles away. An experiment with particular quell'antenna remain in the history of this civilization: a lightning came from the globe of iron at the top antenna, grew in size to become a world power that sent him to the sky lightning crackling at least 50 meters in length. The area was filled with the rumble of thunder and the grass took on a bright green color as if there was phosphorescence. The fact was certainly more traumatic than that borne by the inhabitants, who, walking in the streets, saw electric sparks that shoot out from their feet on the pavement ended. After such a show even the financier JP Morgan, believes the inventive genius of Tesla, well-invested $ 150,000 in the project of the transmission of energy. So Nikola Tesla moved to New York and began the construction of the first communications tower in Long Island: the Wardenclyffe. That was in 1900.
Wardenclyffe The imposing tower, built by Tesla on Long Island.
Three years later, when the Wardenclyffe was completed, Tesla announced another of his discoveries: would have been enough to give a powerful energy to their transmitters to transform the Earth's lithosphere in a giant holder. It was enough to put into practice a metal stick into the ground, connected to a transformer to get electricity at will. Tesla was of the opinion that to generate the initial energy was sufficient to use hydropower. The weakness of such invention was that if the transmitter had sent, instead of around the globe uniformly, a large amount of energy in one place, then it would been a total destruction. According to calculations, this system could easily send an energy equal to a 10-megaton nuclear bomb. The History reminds us that Tesla never had the chance to experience its revolutionary invention. In 1903, Morgan withdrew his financial supporter. Surely this American tycoon has pointed out that a radius of 10 megatons of death could also be good, but to provide electricity in an unlimited and free to the whole world was unthinkable. At that point, Tesla was abandoned by all. Heavily in debt, had to sell off the Colorado Springs lab for a few dollars, so that in 1906 no longer had money to pay employees' wages Wardenclyffe, which remained empty. It was at this time that Tesla's life began to be clothed in mystery.
When the world began the race arms, which then will lead to World War I, Tesla tried to bring water to his "mill" offering a system of destruction more powerful. It is believed however that they were only rumors, supported by an unusual event such as the disappearance of Jena the French ship which blew up under mysterious circumstances. It is known that Tesla was neutral before quest'esecrabile gesture. He had stated previously, that his transmitter could have sent "shock waves" of such intensity as to cause an explosion in santabarbara a warship and blow it apart. The fact that the Wardenclyffe, without operators, would work without problems meant that there were state, then speculate on its use in the case of Tunguska. In practice
in 1908 Tesla seems to have said: "Mine is not a dream. You can create a wireless system that can make any area of \u200b\u200bthe Earth uninhabitable, without exposing the population of other parts to serious damage or have adverse incidents .
There is much uncertainty, considering that Tesla, in a desperate attempt to get financial aid for his research, he has to let go of quite specific statements.
is known, however, that until 1915 Tesla did not have any funding that could help him, so that the Wardenclyffe was razed in 1917. A strange thing is that he had the habit July 10 of each year on his birthday, to make sensational revelations about the future of electricity. Statements were so dramatic that the rite ended up being ridiculous.
In 1935 he tried to engage again in a mogul Morgan defense project that uses laser beams of particles similar to those we know today through the film of "Star Trek".
When Tesla died, his inventions were requisitioned by the U.S. government and, much later, returned to his nephew, except on death ray.
The fact that Tesla might have actually triggered the Wardenclyffe Tower to determine the devastation of the Tunguska event remains a conjecture that some authors does not take account of some very important facts. Nevertheless, I repeat, that Tesla was not in a position to potentially make a similar experience. One of the technical facts that he had to overcome was the availability of primary energy to power up to 30 megatons end. It was not possible, then perform a similar experiment in secret and above the hydroelectric plant in question could not be absolutely one. An experiment of this kind to those who could he do? Perhaps the U.S. government? Another inconsistency is found in the likely trajectory suggested that the fireball energy should have made.
Alleged trajectory of the fireball that would have struck the Tunguska with the energy generated by Wardenclyffe Tower, designed by the brilliant idea of \u200b\u200bNikola Tesla.
analyzing the geometric aspect, it must have come from the north and curvilinear features to hit the uninhabited area of \u200b\u200bthe Tunguska: the opposite of what the witnesses reported the majority of the time.
I also think that, by failing to present tangible evidence yet of a real trial to that effect, it is quite difficult to determine whether the effects can be compared with actual measurements found in the taiga, with all the peculiarities of the event, including explosion, in terms have already been analyzed.
One thing is certain, however: the invention of Nikola Tesla, conosciuta come la trasmissione d’energia elettrica senza fili, verrà in seguito applicata ma non per scopi benefici. Tesla in proposito lasciò scritto: "Il successo pratico di un’idea, indipendentemente dalle sue qualità inerenti, dipende dalla scelta dei contemporanei. Se è al passo coi tempi, essa viene rapidamente adottata; in caso contrario, è destinata a vivere come un germoglio che sboccia, attirato dalle lusinghe e dal calore del primo sole, per essere poi danneggiato e crescere con difficoltà a causa del gelo che s’impone."
Questo gelo è stato recentemente sciolto, purtroppo. Nell’evoluzione tecnologica militare degli Stati Uniti da qualche anno è comparso il progetto HAARP (High Frequency Active Auroral Research Project). The Pentagon is making us believe that this is a harmless experiment, as we are dealing with a weapon that acts on the ionosphere with indescribable likely developments for living beings. In 1987, the adviser of the Atlantic Richfield Corporation (ARCO), physicist Bernard J. Eastlund, he applied all his intellectual resources to resume the patent of Nikola Tesla Wardenclyffe. The new system was called "Method and apparatus for altering a region of the atmosphere, ionosphere and / or magnetosphere. Indeed, the method was used to Eastlund to discover large deposits of natural gas that the oil company ARCO was looking for in Alaska. When
studies had achieved some success, interrupted the nuclear physicist Edward Teller (one of the staunchest U.S. scientists, which is devoted to building an atomic bomb, and especially of the hydrogen), which gave rise to new initiatives secret, which could to continue the military system of "Star War". In a short time Alaska became the last frontier of military research.
The mammoth and several antennas located in Gakona (Alaska), part of the HAARP Project.
The main installation of the Project HAARP in Alaska is located in Gakona, about 150 miles northeast of Anchorage. The choice This site was made for three basic reasons:
• Its proximity to the Pole and then to the zone of concentration of the magnetic lines of our planet.
• The presence of remarkable natural energy sources in the subsurface.
• Its distance from urban centers.
The HAARP program led to the construction of a system of 360 antennas, 23 meters high, capable of transmitting, with the aim to improve military communications, a "beam" of high frequency energy in the ionosphere. The ionosphere is the part of atmospheric region that begins about 50 km above sea level and ends around 800 km According to the latest rumors, this weapon would be capable interfering with extensive areas of the atmosphere and thus, according to military logic, missiles and shoot down airplanes and anything else.
There are more than 400 patents related to HAARP project and the majority of these projects are offensive or better are offensive weapons. There is always the logic that the system uses the radiation beam of energy directly from the earth into space. You can carry the high frequency energy in an area where a receiving antenna has been installed, but can radiate as well as military areas, even in urban centers. Of course not escaped the military high command to use a similar technology to reduce flying objects of Origin extraterrestrial, if this is of course possible. Pure Soviet scientists have devoted themselves to such research for over 25 years, until the political change and the dismantling of the USSR led to a dramatic weakening economy, with consequent deprivation of the necessary financial support to institutions of investigation.
Headquartered in Gakona, there are other similar installations, located in various parts of the planet. The first can be located in Arecibo (Puerto Rico), the second to Alaska in Fairbanks, the third in Tromso (Norway), then to Pine Bush Steeplebush in Australia and finally to England. Surely you are building other facilities of its kind in the southern hemisphere of the planet.
It was learned that the pilot plant of Gakona you are able to broadcast to 1.7 billion watts into the atmosphere. This is actually the negative development of the invention of Tesla. He hated the war and in this regard, he said: "We can abolish war by outlawing. There may be terminated by disarming the strong. But you can stop making all countries able to defend themselves. I just found a new weapon of defense which, if adopted, will completely transform the relations between nations. make them all, big and small they are, invulnerable to any attack from land, sea or air. We must, first, build a great workshop for the manufacture of this weapon, but when it is completed, you can destroy people and machines within a radius of 320 km "
In 1934, Tesla described in an article similar to the laser equipment, saying:" This instrument projects particles which may be relatively large or microscopic, that are used to transfer energy at a great distance a million times stronger than that achievable with any other range. So a stream thinner than a strand can transmit thousands of horsepower. And nothing can resist. "
Because of his statements, it was rumored that Tesla had invented a" death ray. "He immediately replied:" The invention I mentioned, on several occasions, he has nothing to do with what is commonly called the 'death ray'. "
Let me conclude on Nikola Tesla, one of the most brilliant men appeared on this planet, with its symbolic phrase that describes its nature as a scientist in a superlative: "The Gift of the force of reason comes from God, from being the Divine, and if you concentrate our minds on that truth, we establish harmony with this great force. My mother taught me to seek all truth in the Bible. - Nikola Tesla ".
When Veins On Breast Hurts?
theory of relativity
Theory of Relativity
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In physics, the term relativity is refer generically to the mathematical transformations to be applied to descriptions of phenomena in the transition between two frames of reference in relative motion. The expression theory of relativity is used to refer to one of the particular theories, such as the theory of special relativity or general Einstein, who as a fundamental element in a particular principle of relativity.
Evolution of the theory of relativity
The ancient Greeks began to wonder about nature, its order (cosmos) and the possibility of the existence of principles and laws of nature. Almost all the ancient philosophers, including Heraclitus, Parmenides, Zeno, Leucippus, Democritus, Plato and Aristotle, dealing with issues that are at least partly related to what is now called physics, the word has Greek origins and which represents "the things of nature." In Aristotle's physics are those that could be regarded as the first theory, in the modern sense, on the motion, although he is not a precursor of the principle of inertia, one can already recognize in his writings, some thematic still present. Some scholars have found there relativistic intuitions.
Modern science begins with the fundamental assumption, due to Galileo Galilei, the laws of physics have the same form with respect to any reference system is adopted which is worth the principle of inertia. This assumption was established in 1609, is now called the principle of Galilean relativity, which is still valid. It is based on Galileo's great insight in the composition of motions, and then the law of the sum of velocities: if two observers are in relative motion between them and each of them moves with consistency, so that the relative velocity is constant, will measure spaces different compared to the same event, but the "form" of their comments is the same as algebra. Still, nothing is said about the timing.
The concept that time is linked to the reference system is the proper and original contribution of Albert Einstein. In fact, when Newton, reading and studying carefully is the Dialogue on the Chief World Systems, is the Discourses on a New Science, interpreted the original insights in these geometrically in the writings of Galileo, the assimilated and made his own, thus giving rise to the mathematical form of mechanics and physics, he faced the principle of relativity and it became manifest that its adoption would involve so need a reference in which the first law of motion (Galileo's law of inertia) were in full force. The real problem however was and still is where to place the reference system: solved the dilemma by asserting that all the spaces for were references to an absolute space, the only existing unchanged and unchangeable, and the immutability of absolute space was nothing but the expression of the existence of an absolute time, which flows uniformly, pervading all space overall.
Newton's solution was brilliant and it became a paradigm that will last for centuries. Even Galileo, however, with his attempts to measure the speed of light terrestrial, expressed doubts unresolved at the time about how we should understand the principle of relativity and the principle of inertia so closely related to it. These doubts remained dormant, overshadowed by the splendor of the great success of Newtonian mechanics, until 1905.
With the advent of Maxwell's equations, the Lorentz transformations, and finally the theory of relativity Einstein is not the concept, which had been taken for granted, of absolute time. The restricted theory assumes that if the speed of light is constant then the time and space are variables. Time and space are linked together to form what is called space-time. When you are moving relative to a reference system time slows down and the mass increases increasingly as one approaches the speed of light. From here we deduce the reason why the theory of relativity says that you can not exceed or even reach the speed of light, time would stop and the mass would become infinite. General relativity postulates equality instead of gravitational mass and inertial mass, and derive from the "shape" of spacetime, ie its general metric.
It says "theory" of relativity theory, not because it is a simple yet to be confirmed, but simply because that is the name given at birth and since then has never been changed. Although it has limitations, since it considers the matter and still leave out the spacetime and quantum mechanics, remains one of the most precise theory ever tested experimentally.
Galilean theory with classical physics was born from the mathematical point of view, is represented by a system of equations linking the coordinates of a reference system with those of a second reference system that moves with constant velocity v with respect to it. The classical transformations are: Galilean relativity, the relativity of Galileo and Newton-Galilean transformation.
Two observers, who must communicate with each other, producing two different positions for the same object that is moving at a given location. Both OI and OII observers who study the motion of a single point P simultaneously determine the position of observer and the other P, PI (OI distance between the observer and the point P) and PI-II (distance between OI and OII) for OI and PII (OII and distance between the point P) and PII-I (distance between the two observers) for OII. Since the Euclidean space is considered, they know that
PI - II = - PII - The
The relationship between the two measures is:
PI = PII + PI - II
or
PII = PI + PII - The
and then both, using the its measures, are able to calculate what the other was measured. It can also do one of two observers make measurements and send another to the calculations. If the observers determine the position of P at different times of the time sequence are then able to determine the position vector of P as a function of time based on the following report
PI (t) = PII (t) + PI - II (t )
The same remarks carried out on the floor you can reproduce in space.
order to relate the two determinations, they must be performed at the same instant. The two observers must then exchange a sign to agree on when to take the measurement and the signal must propagate instantaneously (ie with infinite speed). On the contrary, if the signal should be transmitted with finite speed and note the two observers before walking away from each other, to go and perform their measures, they can synchronize their watches, but you can assume that the movement watch does not alter the timing or pace of the clocks themselves (assuming that the clocks are of the same bill), which can be exchanging test signals, but it still gets a measure "not correct", that is in contradiction with the concept of absolute time.
Galileo was clear the problem, said the attempt to measure the speed of light, only it was based on a terrestrial distance of about 30 km, the distance between two hills in Tuscany, one of which he, with an assistant on the other Hill would have to measure time of propagation of light of a lantern, first covered with a cloth and then explore briefly, the beating of your wrist in this condition could not even hear two beats of his wrist that had already come to light from Galileo deduced that the speed was extremely high, but in his heart was ready to swear it was over. You could then ignore the propagation delay of the signal.
This allows the performance of synchronous measures. This is the nearest of the relativity of Galileo, very valuable in common situations in which the speeds involved are well below the speed of light.
Galilean theories of everything good in the field of mechanics, dynamics and kinematics, have however not valid in the fields of physics such as electromagnetism, in which phenomena and processes involved with speeds comparable to the speed of light in these situations it becomes necessary to measure physical quantities in other inertial systems other than their own, apply the Lorentz transformations, discovered by Albert Einstein in 1905. They are also valid only for speeds small compared to the speed of light, when Einstein's relativistic effects are small compared to the amount at stake. According to the physical
Leonardo Ricci, Galilean relativity was known before its formulation, at least in general principles, related to the relativity of space. In support of his hypothesis, Ricci cites Dante Alighieri. Hell in Canto XVII, namely in verses 115-117, the poet writes:
"He goes very slowly noticing;
Wheels and descends, but not me n'accorgo
except that al viso e di sotto mi venta»
In un articolo pubblicato su Nature nel 2005, Ricci fa notare come Dante fosse ben consapevole della visione scientifica del mondo suo contemporaneo; senza di essa non avrebbe potuto scrivere la sua opera. Di passaggio, Ricci rileva che fu proprio Galileo, profondo conoscitore della Divina Commedia, a fornire una prima stima del diametro del girone, in circa 60 chilometri. Galilei si basò su due indicazioni precise (verso 9 del canto XXIX e ai versi 86-87 del canto XXX). Aggiunge Ricci: «Un fisico contemporaneo può dimostrare che, date queste dimensioni e qualunque sia la velocità, la forza fittizia centrifuga avvertita dal passeggero risulterebbe molto più piccola della forza superficiale dovuta the apparent wind: no force of this kind is mentioned in the narrative. Although such reasoning goes beyond those individuals who had knowledge of the Middle Ages, Dante, however, had sensed that his motion was in fact straight: he indicates the direction, by splitting the vector that describes the apparent wind in the two horizontal components ("the face ") and vertical (below).
Critique of Galilean relativity
In late 1800, Ernst Mach, and several others, including Hendrik Lorentz, clashed with the limitations of the Galilean relativity, can not be used for electromagnetic phenomena. Einstein is thus faced with two different transformations: those of Galileo, mechanism is valid in Lorentz, valid for electromagnetism but without a convincing theoretical support. The situation was very unsatisfactory.
PARADOX: A paradox
, paratroopers from the greek (against) and doxa (opinion), it is something that defies conventional wisdom: it is, in fact (according to the definition given by Mark Sainsbury) of
"a conclusion apparently unacceptable, which is derived from apparently acceptable premises via apparently acceptable reasoning. "
In philosophy and economics the term paradox is used as a synonym of antinomy. In mathematics, we tend to distinguish the concept of paradox, which consists of a proposition perfectly demonstrated, but far from the intuition, the concept of antinomy, which consists of a real logical contradiction.
History
main supporters of the matter was Herbert Dingle, English philosopher. Despite having received numerous logical refutations of Einstein and Bohr, he continued to write to newspapers, and when the latter began to refuse publication, spoke of a plot against him. Statement of the paradox
Consider a spaceship from the Earth in the year 3000; that maintaining a constant speed v reaches the star Wolf 359, 8 kilometers away light years from our planet, and that just arrived, reversed course and returns to the Earth, speed always v. Di una coppia di fratelli gemelli, l'uno salga sull'astronave, mentre l'altro rimanga a Terra.
Volutamente, nei calcoli trascuriamo per semplicità l'accelerazione e la decelerazione della navetta, anche se, per portarsi a velocità relativistiche in tempi brevi, occorrerebbero accelerazioni insostenibili per l'uomo e per la nave.
Supponiamo che v sia di 240.000 km/sec, cioè v = 0.8 c. Per questa velocità si ha:
per cui, secondo la teoria della relatività ristretta, nel sistema in movimento il tempo scorre al 60% del tempo nel sistema in quiete. Quindi:
Nel sistema di riferimento della Terra, l'astronave percorre 8 anni luce in 10 anni nel viaggio forward, and it employs many in the return trip: it then returns to Earth in 3020. On the ship, however, time flows at 60% of the time on Earth, according to the clock of the astronaut and then the trip takes 6 years for the outward and the same for the return: on arrival, therefore, the timing of ' ship is the year 3012. The brother left on Earth is therefore, after the journey, eight years older than his twin.
In the frame of the ship, due to the relativistic contraction of lengths, the distance between Earth and Wolf 359 is shortened to 60%, ie, at 4.8 light years at a rate of 0.8 c, are used then, according to ' watch of the ship, 6 anni per l'andata e 6 per il ritorno, coerentemente con quanto calcolato nel sistema di riferimento della Terra. Ma, poiché in questo sistema di riferimento è la Terra a muoversi, è il suo orologio che va al 60% del tempo dell'astronave: quando l'astronave fa ritorno, sulla Terra sono trascorsi solo 7.2 anni, perciò non è l'anno 3020, ma il 3007, ed è il fratello a bordo dell'astronave ad essere di 4.8 anni più vecchio.
Paradossi di Zenone
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I paradossi di Zenone ci sono stati tramandati attraverso la citazione che ne fa Aristotele nella sua Fisica. Zenone di Elea, discepolo ed amico di Parmenide, per sostenere l'idea del maestro, che la realtà è consists of a unique and immutable, proposed a number of paradoxes that show, strictly speaking, the impossibility of multiplicity and motion, despite the appearances of everyday life.
Zeno's arguments are perhaps the first examples of the method of proof known as reductio ad absurdum or indirect proof. Are also considered a prime example of the dialectical method, later used by the sophists and Socrates.
today is no longer given physical value to the arguments of Zeno, but their influence was very important in the history of philosophy and mathematics.
Zeno's paradoxes are also a useful exercise in logic, to reflect on how Construction of human reasoning. Remember two paradoxes against pluralism and four against the motion.
Paradoxes against pluralism
first paradox
The first paradox, against the plurality of things, says that if things are a lot of them are both a finite and an infinite number: they are finite in that they are neither more nor less how many are endless and as between the first and second there is a third and so on.
Second paradox
The second paradox instead argues that if these units do not have size, the things they have not made up in size, while if the units have a certain size, things made of endless drive will have an infinite magnitude.
Gemini and curved space
The famous twin paradox is based on the fact that the two twin on the ship and that part of the twin who stays still appear symmetrical but in reality they are not, why go back to the astronaut twin should accelerate, thereby losing the quality of the inertial system. If the universe were bent on itself, that would be hypothetically possible from a point and going forward we would find, after going through all the Universe, the very point, what would happen if the astronaut twin compiesse this long journey in motion constant speed and found himself at the same point without having accelerated? Returning to the Earth who would be older? (Of course both would die before the journey can be completed but we admit that human life is very long ...)
according to Einstein relativity with Albert Einstein's theory of relativity was a further development and now we are inclined to associate to this theory the name of German physicist. His theory is composed of two different mathematical models, which go under the name:
Special relativity General relativity Special relativity
relativity, also called special relativity, was the first to be made by Einstein, with the ' article "Zur Elektrodynamik bewegter Körper (Electrodynamics of Moving Bodies), 1905, to reconcile the principle of Galilean relativity with the equations of electromagnetic waves.
Prior to that end, several theories were proposed which were based on the existence of a means of propagation electromagnetic waves, called ether, but no experiment was able to measure the speed of an object relative to the ether. In particular, with the Michelson-Morley experiment had shown that the speed of light is constant in all directions, regardless of the motion of the Earth, thus reflecting the so-called "ether wind".
Einstein's theory then discards the concept of ether, which today is no longer used by physicists, even if informally, there is talk of light to indicate the space in which electromagnetic waves propagate.
relativity examines what happens when observers move relative to each other but does not take into account the effects of the gravitational field that will instead be introduced in the theory of general relativity. It accepts the principle of Galileo under which it is not possible to discern whether an observer is in motion with respect to another if the target system will take two observers, given that space is homogeneous and isotropic. The theory is based on two assumptions:
The laws of physics are the same for all observers in inertial motion.
The speed of light in vacuum is constant in any frame of reference
general relativity theory of general relativity was presented as a series of readings at the Prussian Academy of Sciences, from November 25, 1915, after a long period of preparation . There is controversy regarding the publication of a vintage field equations between the German mathematician David Hilbert and Einstein, but some documents with some confidence ascribe primacy to Einstein.
The foundation of general relativity is the assumption, known as the principle of equivalence, that acceleration is indistinguishable from the effects of a field gravity, and therefore that the inertial mass is equal to the gravitational mass. Using the tensor calculus, Einstein was able to determine the structure of spacetime, starting from three simple assumptions of special and general relativity.
While proving extremely accurate over time, general relativity is a classical theory, a theory of the continuum, as developed independently by quantum mechanics and have never been reconciled with it, as well as quantum physics, but may include special relativity, does not take account of general relativity.
It may be assumed that if Einstein had been less skeptical about the mechanics Quantum, which had also contributed to the history of physics would have been different. In general relativity limits are due mainly to the treatment of singularities and states of matter in which the gravitational interactions and quantum come to have the same order of magnitude. Among the changes proposed by this theory, the most famous and investigated are string theory and loop quantum gravity.
relativity in an absolute sense is a difficulty, since it refers to the absolute void, which in reality does not exist, since even the single attraction that changes the speed of the bodies through the mass, in fact, actually a ray of light that falls perpendicular to a liquid at low light resistance deviates, understand that doing so decreases its kinetic rate.
E = mc ²
The formula E = mc ², his theory of relativity is one of the most famous mathematical formulas and probably the most famous of all, this is thanks to its extreme elegance and simplicity. In essence, the formula takes into account:
E = energy m = mass
c = speed of light
also becomes easy to understand how mass and energy are equivalent and how they are two sides of same coin, is essentially the mass highly concentrated energy. It is this equivalence between mass and energy explains how, by concentrating a large amount of energy can create mass, and so on, as well as you can get a huge amount of energy from a small mass.
A practical application of this concept, you can see the takeoff of the Space Shuttle. When off, all the fuel used only about a gram becomes energy, everything else is converted into smoke and combustion products. Using nuclear energy yield increases, but in an ordinary atom bomb, for example, is converted into energy only about 0.5% of the total mass of fissile material. If it were possible to convert the entire mass into energy, the need energy of Earth's inhabitants would undoubtedly solved: one kilogram of matter corresponds to 25 billion kWh (25,000 GWh). This enormous amount of energy equivalent to the monthly consumption of electricity in Italy (which in 2004 was an average of 25,374 GWh). The mass-energy equivalence has demonstrated its awesome power with atomic bombs. The Hiroshima bomb was 13 kilotons, equivalent to 54.6 trillion joules (13 x 4.2 x 10 ¹ ² J), but this energy is only 60% of what was released from the conversion of one gram of matter, which amounted to 90,000 billion joules.
The formula expressed in any reference system energy total stop of a particle.
If the body is in motion, the correct formula (and complete) is:
with.
For a body starting from rest is that v = 0 and γ = 0, and find that particular case.
The mass is here understood as a relativistic mass of the body, to distinguish from the inertial mass m The inertial mass can be considered a property of the body, as in an inertial motion, it remains unchanged. In an inertial motion, do not be a difference of gravity, speed, direction and orientation of motion are unaffected. In contrast a change in the gravitational coimplica a variation of the velocity vector: If you change the speed the body is its mass anmodificare the external field, by contrast, a significant variation in the gravitational environment can clearly modify the intensity and path of motion.
The concept of relativistic mass can be understood by imagining a grave of one kg of weight, which falls to the ground at a speed of 100 km / h does the same damage of a grave of a ton of weight falling from a few inches height. The power of the damage depends on the momentum, mass and velocity factors. The concept of mass reativistica, extends the concept of gravitational mass, as Einstein's theory generalizes the gravity of Newton.
With this in mind it makes sense to define a mass that depends on the speed (and it would be the product of its mass, inertia, for the term γ):
m = m (v), and in particular that:
, and that:
.
In other words, the relativistic mass is not a property independent of the speed v, but grows with it. When speed is approximate to that of light, the mass of the body tends to infinity.
To accelerate a body and a mass different from zero, aside from the speed of light would require infinite energy. This would be necessary not only to overcome the speed of light, but to get at least a small amount of what you want, an infinitesimal.
A second reason for the qule can not be overcome by the speed of light, derived from the equation explaining the contraction / expansion of space-time in special relativity.
assumptions about the origins and authorship
The genesis of the theory of relativity, as it was developed by Albert Einstein, is surrounded by a sort of mystery that comes back to surface periodically, generating discussion in the scientific world. In the eighties a group of scholars brought forward in an Italian newspaper, Il Giornale di Vicenza, a long fight to support an argument that Einstein's famous equation, E = mc ², was made to derive directly the study hypothesis of ether in the life of the universe, presented in 1903 at the Royal Institute of Sciences, Letters and Arts in Schio (VI) by Olinto De Pretto (1867-1921). De Pretto, a graduate in agricultural, industrial occupation but passionate about physics and geology, but never did not claim authorship - even in a nutshell - the famous formula. In 1999, the "De Pretto Case" has found new life, however, by Umberto Bartocci, professor of mathematics at the University of Perugia, who narrated his vision of the facts in the pamphlet - also received with skepticism by 'academic environment - Albert Einstein and Olinto De Pretto, the true history of the world's most famous formula. But Einstein, based on the assumptions made in the time around his work, may have been assisted in its analysis on general relativity by another Italian: the mathematician Gregorio Ricci Curbastro (1853-1925) who devised their own special tensor calculations. The curvature of spacetime
A layman's famous illustration of the curvature of spacetime caused by mass, represented here by the Earth.
The theory states that spacetime is more or less curved by the presence of a mass and another smaller mass moves then the effect of this curvature.
Often, it portrays the situation as a ball that deforms the floor of the pool with his weight, while another ball is accelerated by this deformation of the plan and in fact drawn from the first.
This is just a simplification to the size shown here, as is to be warped space-time and not only the spatial dimensions, which is impossible to depict and difficult to design.
The only situation that we can correctly portray is that of a universe in a spatial and a temporal dimension. Any material point is represented by a line (world line), not a point, which provides its position all the time: that is stationary or in motion will only change the slope of this line. Now we turn to this universe using the third dimension: what was once the line describing a point, it is now a surface.
on a curved surface that is non-Euclidean geometry, in particular, can draw a triangle whose angles do not provide added 180 and is also possible to proceed in the same direction, returning after a certain time to the starting point.
description of gravitation
Every particle of matter moves at constant speed along a curve, called geodesic that at any time (ie locally) can be considered straight. Its speed is the ratio between the spatial distance traveled and the proper time, where time is right that measured in the reference of the particle, while the spatial distance depends on the metric that defines the structure of space-time. The curvature determines the actual shape of geodesics, and then the body follows a path over time.
In other words, a free body moves in space-time along a geodesic always in the same way as in classical mechanics a body is not subjected to forces moving along a straight line. If the structure of space-time at that point is flat, the geodesic will be just a straight line, otherwise it will take different forms, but the body will follow anyway. In this way, the gravity is to be incorporated into the structure of space-time.
Once again, it should be Note that this curvature is applied not only to the spatial coordinates, but also to that time, this leads to significant practical difficulties in groped to imagine such a surface in 4 dimensions.
Fundamentals of the theory
Even electromagnetic pulses are deflected by the gravitational force on the theory of relativity. In the image a graphical representation of a signal from a probe that is deflected by the gravity of the Sun reaches Earth
In the presence of accelerated systems (or, which is the same systems under the influence of gravity), we can defined as areas with local inertial reference and for short periods. This corresponds to approximated with a flat surface that would be a curved surface on a large scale. In such situations still apply Newton's laws.
Now the principle of equivalence states that there is no local experiment to distinguish between a free fall in a gravitational field and uniform motion in the absence of field (Einstein's lift)
Mathematically, Einstein described space-time as a pseudo Riemann-space to 4 dimensions, and its field equation linking the curvature at a point in the energy tensor at that point, as such a tensor dependent on the density of matter and energy.
The field equation given by Einstein is not the only possible, but is distinguished by the simplicity of the coupling between matter and energy and curvature.
This equation contains a term Λ, called the cosmological constant, introduced by Einstein to allow a static universe. In ten years later, Hubble observations showed that the universe is (or appears) in the expansion and the cosmological term was omitted (Einstein himself thought it his introduction the biggest mistake he had committed in life). But it seems that Einstein was sentenced to be right even when wrong: as it happened to quantum theory, which helped to establish certain principles and then feel bad (like the Heisenberg uncertainty principle), even the cosmological constant has been rehabilitated. In 1998, observation of red shift of distant supernovae, has forced astronomers to use a cosmological constant to explain the accelerating expansion of the Universe. 
Theory of Relativity
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In physics, the term relativity is refer generically to the mathematical transformations to be applied to descriptions of phenomena in the transition between two frames of reference in relative motion. The expression theory of relativity is used to refer to one of the particular theories, such as the theory of special relativity or general Einstein, who as a fundamental element in a particular principle of relativity.
Evolution of the theory of relativity
The ancient Greeks began to wonder about nature, its order (cosmos) and the possibility of the existence of principles and laws of nature. Almost all the ancient philosophers, including Heraclitus, Parmenides, Zeno, Leucippus, Democritus, Plato and Aristotle, dealing with issues that are at least partly related to what is now called physics, the word has Greek origins and which represents "the things of nature." In Aristotle's physics are those that could be regarded as the first theory, in the modern sense, on the motion, although he is not a precursor of the principle of inertia, one can already recognize in his writings, some thematic still present. Some scholars have found there relativistic intuitions.
Modern science begins with the fundamental assumption, due to Galileo Galilei, the laws of physics have the same form with respect to any reference system is adopted which is worth the principle of inertia. This assumption was established in 1609, is now called the principle of Galilean relativity, which is still valid. It is based on Galileo's great insight in the composition of motions, and then the law of the sum of velocities: if two observers are in relative motion between them and each of them moves with consistency, so that the relative velocity is constant, will measure spaces different compared to the same event, but the "form" of their comments is the same as algebra. Still, nothing is said about the timing.
The concept that time is linked to the reference system is the proper and original contribution of Albert Einstein. In fact, when Newton, reading and studying carefully is the Dialogue on the Chief World Systems, is the Discourses on a New Science, interpreted the original insights in these geometrically in the writings of Galileo, the assimilated and made his own, thus giving rise to the mathematical form of mechanics and physics, he faced the principle of relativity and it became manifest that its adoption would involve so need a reference in which the first law of motion (Galileo's law of inertia) were in full force. The real problem however was and still is where to place the reference system: solved the dilemma by asserting that all the spaces for were references to an absolute space, the only existing unchanged and unchangeable, and the immutability of absolute space was nothing but the expression of the existence of an absolute time, which flows uniformly, pervading all space overall.
Newton's solution was brilliant and it became a paradigm that will last for centuries. Even Galileo, however, with his attempts to measure the speed of light terrestrial, expressed doubts unresolved at the time about how we should understand the principle of relativity and the principle of inertia so closely related to it. These doubts remained dormant, overshadowed by the splendor of the great success of Newtonian mechanics, until 1905.
With the advent of Maxwell's equations, the Lorentz transformations, and finally the theory of relativity Einstein is not the concept, which had been taken for granted, of absolute time. The restricted theory assumes that if the speed of light is constant then the time and space are variables. Time and space are linked together to form what is called space-time. When you are moving relative to a reference system time slows down and the mass increases increasingly as one approaches the speed of light. From here we deduce the reason why the theory of relativity says that you can not exceed or even reach the speed of light, time would stop and the mass would become infinite. General relativity postulates equality instead of gravitational mass and inertial mass, and derive from the "shape" of spacetime, ie its general metric.
It says "theory" of relativity theory, not because it is a simple yet to be confirmed, but simply because that is the name given at birth and since then has never been changed. Although it has limitations, since it considers the matter and still leave out the spacetime and quantum mechanics, remains one of the most precise theory ever tested experimentally.
Galilean theory with classical physics was born from the mathematical point of view, is represented by a system of equations linking the coordinates of a reference system with those of a second reference system that moves with constant velocity v with respect to it. The classical transformations are: Galilean relativity, the relativity of Galileo and Newton-Galilean transformation.
Two observers, who must communicate with each other, producing two different positions for the same object that is moving at a given location. Both OI and OII observers who study the motion of a single point P simultaneously determine the position of observer and the other P, PI (OI distance between the observer and the point P) and PI-II (distance between OI and OII) for OI and PII (OII and distance between the point P) and PII-I (distance between the two observers) for OII. Since the Euclidean space is considered, they know that
PI - II = - PII - The
The relationship between the two measures is:
PI = PII + PI - II
or
PII = PI + PII - The
and then both, using the its measures, are able to calculate what the other was measured. It can also do one of two observers make measurements and send another to the calculations. If the observers determine the position of P at different times of the time sequence are then able to determine the position vector of P as a function of time based on the following report
PI (t) = PII (t) + PI - II (t )
The same remarks carried out on the floor you can reproduce in space.
order to relate the two determinations, they must be performed at the same instant. The two observers must then exchange a sign to agree on when to take the measurement and the signal must propagate instantaneously (ie with infinite speed). On the contrary, if the signal should be transmitted with finite speed and note the two observers before walking away from each other, to go and perform their measures, they can synchronize their watches, but you can assume that the movement watch does not alter the timing or pace of the clocks themselves (assuming that the clocks are of the same bill), which can be exchanging test signals, but it still gets a measure "not correct", that is in contradiction with the concept of absolute time.
Galileo was clear the problem, said the attempt to measure the speed of light, only it was based on a terrestrial distance of about 30 km, the distance between two hills in Tuscany, one of which he, with an assistant on the other Hill would have to measure time of propagation of light of a lantern, first covered with a cloth and then explore briefly, the beating of your wrist in this condition could not even hear two beats of his wrist that had already come to light from Galileo deduced that the speed was extremely high, but in his heart was ready to swear it was over. You could then ignore the propagation delay of the signal.
This allows the performance of synchronous measures. This is the nearest of the relativity of Galileo, very valuable in common situations in which the speeds involved are well below the speed of light.
Galilean theories of everything good in the field of mechanics, dynamics and kinematics, have however not valid in the fields of physics such as electromagnetism, in which phenomena and processes involved with speeds comparable to the speed of light in these situations it becomes necessary to measure physical quantities in other inertial systems other than their own, apply the Lorentz transformations, discovered by Albert Einstein in 1905. They are also valid only for speeds small compared to the speed of light, when Einstein's relativistic effects are small compared to the amount at stake. According to the physical
Leonardo Ricci, Galilean relativity was known before its formulation, at least in general principles, related to the relativity of space. In support of his hypothesis, Ricci cites Dante Alighieri. Hell in Canto XVII, namely in verses 115-117, the poet writes:
"He goes very slowly noticing;
Wheels and descends, but not me n'accorgo
except that al viso e di sotto mi venta»
In un articolo pubblicato su Nature nel 2005, Ricci fa notare come Dante fosse ben consapevole della visione scientifica del mondo suo contemporaneo; senza di essa non avrebbe potuto scrivere la sua opera. Di passaggio, Ricci rileva che fu proprio Galileo, profondo conoscitore della Divina Commedia, a fornire una prima stima del diametro del girone, in circa 60 chilometri. Galilei si basò su due indicazioni precise (verso 9 del canto XXIX e ai versi 86-87 del canto XXX). Aggiunge Ricci: «Un fisico contemporaneo può dimostrare che, date queste dimensioni e qualunque sia la velocità, la forza fittizia centrifuga avvertita dal passeggero risulterebbe molto più piccola della forza superficiale dovuta the apparent wind: no force of this kind is mentioned in the narrative. Although such reasoning goes beyond those individuals who had knowledge of the Middle Ages, Dante, however, had sensed that his motion was in fact straight: he indicates the direction, by splitting the vector that describes the apparent wind in the two horizontal components ("the face ") and vertical (below).
Critique of Galilean relativity
In late 1800, Ernst Mach, and several others, including Hendrik Lorentz, clashed with the limitations of the Galilean relativity, can not be used for electromagnetic phenomena. Einstein is thus faced with two different transformations: those of Galileo, mechanism is valid in Lorentz, valid for electromagnetism but without a convincing theoretical support. The situation was very unsatisfactory.
PARADOX: A paradox
, paratroopers from the greek (against) and doxa (opinion), it is something that defies conventional wisdom: it is, in fact (according to the definition given by Mark Sainsbury) of
"a conclusion apparently unacceptable, which is derived from apparently acceptable premises via apparently acceptable reasoning. "
In philosophy and economics the term paradox is used as a synonym of antinomy. In mathematics, we tend to distinguish the concept of paradox, which consists of a proposition perfectly demonstrated, but far from the intuition, the concept of antinomy, which consists of a real logical contradiction.
History
main supporters of the matter was Herbert Dingle, English philosopher. Despite having received numerous logical refutations of Einstein and Bohr, he continued to write to newspapers, and when the latter began to refuse publication, spoke of a plot against him. Statement of the paradox
Consider a spaceship from the Earth in the year 3000; that maintaining a constant speed v reaches the star Wolf 359, 8 kilometers away light years from our planet, and that just arrived, reversed course and returns to the Earth, speed always v. Di una coppia di fratelli gemelli, l'uno salga sull'astronave, mentre l'altro rimanga a Terra.
Volutamente, nei calcoli trascuriamo per semplicità l'accelerazione e la decelerazione della navetta, anche se, per portarsi a velocità relativistiche in tempi brevi, occorrerebbero accelerazioni insostenibili per l'uomo e per la nave.
Supponiamo che v sia di 240.000 km/sec, cioè v = 0.8 c. Per questa velocità si ha:
per cui, secondo la teoria della relatività ristretta, nel sistema in movimento il tempo scorre al 60% del tempo nel sistema in quiete. Quindi:
Nel sistema di riferimento della Terra, l'astronave percorre 8 anni luce in 10 anni nel viaggio forward, and it employs many in the return trip: it then returns to Earth in 3020. On the ship, however, time flows at 60% of the time on Earth, according to the clock of the astronaut and then the trip takes 6 years for the outward and the same for the return: on arrival, therefore, the timing of ' ship is the year 3012. The brother left on Earth is therefore, after the journey, eight years older than his twin.
In the frame of the ship, due to the relativistic contraction of lengths, the distance between Earth and Wolf 359 is shortened to 60%, ie, at 4.8 light years at a rate of 0.8 c, are used then, according to ' watch of the ship, 6 anni per l'andata e 6 per il ritorno, coerentemente con quanto calcolato nel sistema di riferimento della Terra. Ma, poiché in questo sistema di riferimento è la Terra a muoversi, è il suo orologio che va al 60% del tempo dell'astronave: quando l'astronave fa ritorno, sulla Terra sono trascorsi solo 7.2 anni, perciò non è l'anno 3020, ma il 3007, ed è il fratello a bordo dell'astronave ad essere di 4.8 anni più vecchio.
Paradossi di Zenone
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I paradossi di Zenone ci sono stati tramandati attraverso la citazione che ne fa Aristotele nella sua Fisica. Zenone di Elea, discepolo ed amico di Parmenide, per sostenere l'idea del maestro, che la realtà è consists of a unique and immutable, proposed a number of paradoxes that show, strictly speaking, the impossibility of multiplicity and motion, despite the appearances of everyday life.
Zeno's arguments are perhaps the first examples of the method of proof known as reductio ad absurdum or indirect proof. Are also considered a prime example of the dialectical method, later used by the sophists and Socrates.
today is no longer given physical value to the arguments of Zeno, but their influence was very important in the history of philosophy and mathematics.
Zeno's paradoxes are also a useful exercise in logic, to reflect on how Construction of human reasoning. Remember two paradoxes against pluralism and four against the motion.
Paradoxes against pluralism
first paradox
The first paradox, against the plurality of things, says that if things are a lot of them are both a finite and an infinite number: they are finite in that they are neither more nor less how many are endless and as between the first and second there is a third and so on.
Second paradox
The second paradox instead argues that if these units do not have size, the things they have not made up in size, while if the units have a certain size, things made of endless drive will have an infinite magnitude.
Gemini and curved space
The famous twin paradox is based on the fact that the two twin on the ship and that part of the twin who stays still appear symmetrical but in reality they are not, why go back to the astronaut twin should accelerate, thereby losing the quality of the inertial system. If the universe were bent on itself, that would be hypothetically possible from a point and going forward we would find, after going through all the Universe, the very point, what would happen if the astronaut twin compiesse this long journey in motion constant speed and found himself at the same point without having accelerated? Returning to the Earth who would be older? (Of course both would die before the journey can be completed but we admit that human life is very long ...)
according to Einstein relativity with Albert Einstein's theory of relativity was a further development and now we are inclined to associate to this theory the name of German physicist. His theory is composed of two different mathematical models, which go under the name:
Special relativity General relativity Special relativity
relativity, also called special relativity, was the first to be made by Einstein, with the ' article "Zur Elektrodynamik bewegter Körper (Electrodynamics of Moving Bodies), 1905, to reconcile the principle of Galilean relativity with the equations of electromagnetic waves.
Prior to that end, several theories were proposed which were based on the existence of a means of propagation electromagnetic waves, called ether, but no experiment was able to measure the speed of an object relative to the ether. In particular, with the Michelson-Morley experiment had shown that the speed of light is constant in all directions, regardless of the motion of the Earth, thus reflecting the so-called "ether wind".
Einstein's theory then discards the concept of ether, which today is no longer used by physicists, even if informally, there is talk of light to indicate the space in which electromagnetic waves propagate.
relativity examines what happens when observers move relative to each other but does not take into account the effects of the gravitational field that will instead be introduced in the theory of general relativity. It accepts the principle of Galileo under which it is not possible to discern whether an observer is in motion with respect to another if the target system will take two observers, given that space is homogeneous and isotropic. The theory is based on two assumptions:
The laws of physics are the same for all observers in inertial motion.
The speed of light in vacuum is constant in any frame of reference
general relativity theory of general relativity was presented as a series of readings at the Prussian Academy of Sciences, from November 25, 1915, after a long period of preparation . There is controversy regarding the publication of a vintage field equations between the German mathematician David Hilbert and Einstein, but some documents with some confidence ascribe primacy to Einstein.
The foundation of general relativity is the assumption, known as the principle of equivalence, that acceleration is indistinguishable from the effects of a field gravity, and therefore that the inertial mass is equal to the gravitational mass. Using the tensor calculus, Einstein was able to determine the structure of spacetime, starting from three simple assumptions of special and general relativity.
While proving extremely accurate over time, general relativity is a classical theory, a theory of the continuum, as developed independently by quantum mechanics and have never been reconciled with it, as well as quantum physics, but may include special relativity, does not take account of general relativity.
It may be assumed that if Einstein had been less skeptical about the mechanics Quantum, which had also contributed to the history of physics would have been different. In general relativity limits are due mainly to the treatment of singularities and states of matter in which the gravitational interactions and quantum come to have the same order of magnitude. Among the changes proposed by this theory, the most famous and investigated are string theory and loop quantum gravity.
relativity in an absolute sense is a difficulty, since it refers to the absolute void, which in reality does not exist, since even the single attraction that changes the speed of the bodies through the mass, in fact, actually a ray of light that falls perpendicular to a liquid at low light resistance deviates, understand that doing so decreases its kinetic rate.
E = mc ²
The formula E = mc ², his theory of relativity is one of the most famous mathematical formulas and probably the most famous of all, this is thanks to its extreme elegance and simplicity. In essence, the formula takes into account:
E = energy m = mass
c = speed of light
also becomes easy to understand how mass and energy are equivalent and how they are two sides of same coin, is essentially the mass highly concentrated energy. It is this equivalence between mass and energy explains how, by concentrating a large amount of energy can create mass, and so on, as well as you can get a huge amount of energy from a small mass.
A practical application of this concept, you can see the takeoff of the Space Shuttle. When off, all the fuel used only about a gram becomes energy, everything else is converted into smoke and combustion products. Using nuclear energy yield increases, but in an ordinary atom bomb, for example, is converted into energy only about 0.5% of the total mass of fissile material. If it were possible to convert the entire mass into energy, the need energy of Earth's inhabitants would undoubtedly solved: one kilogram of matter corresponds to 25 billion kWh (25,000 GWh). This enormous amount of energy equivalent to the monthly consumption of electricity in Italy (which in 2004 was an average of 25,374 GWh). The mass-energy equivalence has demonstrated its awesome power with atomic bombs. The Hiroshima bomb was 13 kilotons, equivalent to 54.6 trillion joules (13 x 4.2 x 10 ¹ ² J), but this energy is only 60% of what was released from the conversion of one gram of matter, which amounted to 90,000 billion joules.
The formula expressed in any reference system energy total stop of a particle.
If the body is in motion, the correct formula (and complete) is:
with.
For a body starting from rest is that v = 0 and γ = 0, and find that particular case.
The mass is here understood as a relativistic mass of the body, to distinguish from the inertial mass m The inertial mass can be considered a property of the body, as in an inertial motion, it remains unchanged. In an inertial motion, do not be a difference of gravity, speed, direction and orientation of motion are unaffected. In contrast a change in the gravitational coimplica a variation of the velocity vector: If you change the speed the body is its mass anmodificare the external field, by contrast, a significant variation in the gravitational environment can clearly modify the intensity and path of motion.
The concept of relativistic mass can be understood by imagining a grave of one kg of weight, which falls to the ground at a speed of 100 km / h does the same damage of a grave of a ton of weight falling from a few inches height. The power of the damage depends on the momentum, mass and velocity factors. The concept of mass reativistica, extends the concept of gravitational mass, as Einstein's theory generalizes the gravity of Newton.
With this in mind it makes sense to define a mass that depends on the speed (and it would be the product of its mass, inertia, for the term γ):
m = m (v), and in particular that:
, and that:
.
In other words, the relativistic mass is not a property independent of the speed v, but grows with it. When speed is approximate to that of light, the mass of the body tends to infinity.
To accelerate a body and a mass different from zero, aside from the speed of light would require infinite energy. This would be necessary not only to overcome the speed of light, but to get at least a small amount of what you want, an infinitesimal.
A second reason for the qule can not be overcome by the speed of light, derived from the equation explaining the contraction / expansion of space-time in special relativity.
assumptions about the origins and authorship
The genesis of the theory of relativity, as it was developed by Albert Einstein, is surrounded by a sort of mystery that comes back to surface periodically, generating discussion in the scientific world. In the eighties a group of scholars brought forward in an Italian newspaper, Il Giornale di Vicenza, a long fight to support an argument that Einstein's famous equation, E = mc ², was made to derive directly the study hypothesis of ether in the life of the universe, presented in 1903 at the Royal Institute of Sciences, Letters and Arts in Schio (VI) by Olinto De Pretto (1867-1921). De Pretto, a graduate in agricultural, industrial occupation but passionate about physics and geology, but never did not claim authorship - even in a nutshell - the famous formula. In 1999, the "De Pretto Case" has found new life, however, by Umberto Bartocci, professor of mathematics at the University of Perugia, who narrated his vision of the facts in the pamphlet - also received with skepticism by 'academic environment - Albert Einstein and Olinto De Pretto, the true history of the world's most famous formula. But Einstein, based on the assumptions made in the time around his work, may have been assisted in its analysis on general relativity by another Italian: the mathematician Gregorio Ricci Curbastro (1853-1925) who devised their own special tensor calculations. The curvature of spacetime
A layman's famous illustration of the curvature of spacetime caused by mass, represented here by the Earth.
The theory states that spacetime is more or less curved by the presence of a mass and another smaller mass moves then the effect of this curvature.
Often, it portrays the situation as a ball that deforms the floor of the pool with his weight, while another ball is accelerated by this deformation of the plan and in fact drawn from the first.
This is just a simplification to the size shown here, as is to be warped space-time and not only the spatial dimensions, which is impossible to depict and difficult to design.
The only situation that we can correctly portray is that of a universe in a spatial and a temporal dimension. Any material point is represented by a line (world line), not a point, which provides its position all the time: that is stationary or in motion will only change the slope of this line. Now we turn to this universe using the third dimension: what was once the line describing a point, it is now a surface.
on a curved surface that is non-Euclidean geometry, in particular, can draw a triangle whose angles do not provide added 180 and is also possible to proceed in the same direction, returning after a certain time to the starting point.
description of gravitation
Every particle of matter moves at constant speed along a curve, called geodesic that at any time (ie locally) can be considered straight. Its speed is the ratio between the spatial distance traveled and the proper time, where time is right that measured in the reference of the particle, while the spatial distance depends on the metric that defines the structure of space-time. The curvature determines the actual shape of geodesics, and then the body follows a path over time.
In other words, a free body moves in space-time along a geodesic always in the same way as in classical mechanics a body is not subjected to forces moving along a straight line. If the structure of space-time at that point is flat, the geodesic will be just a straight line, otherwise it will take different forms, but the body will follow anyway. In this way, the gravity is to be incorporated into the structure of space-time.
Once again, it should be Note that this curvature is applied not only to the spatial coordinates, but also to that time, this leads to significant practical difficulties in groped to imagine such a surface in 4 dimensions.
Fundamentals of the theory
Even electromagnetic pulses are deflected by the gravitational force on the theory of relativity. In the image a graphical representation of a signal from a probe that is deflected by the gravity of the Sun reaches Earth
In the presence of accelerated systems (or, which is the same systems under the influence of gravity), we can defined as areas with local inertial reference and for short periods. This corresponds to approximated with a flat surface that would be a curved surface on a large scale. In such situations still apply Newton's laws.
Now the principle of equivalence states that there is no local experiment to distinguish between a free fall in a gravitational field and uniform motion in the absence of field (Einstein's lift)
Mathematically, Einstein described space-time as a pseudo Riemann-space to 4 dimensions, and its field equation linking the curvature at a point in the energy tensor at that point, as such a tensor dependent on the density of matter and energy.
The field equation given by Einstein is not the only possible, but is distinguished by the simplicity of the coupling between matter and energy and curvature.
This equation contains a term Λ, called the cosmological constant, introduced by Einstein to allow a static universe. In ten years later, Hubble observations showed that the universe is (or appears) in the expansion and the cosmological term was omitted (Einstein himself thought it his introduction the biggest mistake he had committed in life). But it seems that Einstein was sentenced to be right even when wrong: as it happened to quantum theory, which helped to establish certain principles and then feel bad (like the Heisenberg uncertainty principle), even the cosmological constant has been rehabilitated. In 1998, observation of red shift of distant supernovae, has forced astronomers to use a cosmological constant to explain the accelerating expansion of the Universe.
Tuesday, May 13, 2008
Dental School Studying Funny
The vision of the new world of Nikola Tesla
The words of Nikola Tesla which responds to the drafting of the New York Times, seeking to clarify certain concepts that were evidently misunderstood - in a note dated 11 March 1908. The New York Times, 21 April 1908, will report in turn to its replication in an article intolerance " How the Electrician's Lamp of Aladdin May Construct New Worlds ", as if to ridicolarizzare the futuristic vision of the scientist Nikola Tesla.
Scientific theories of Tesla have been from the outset, the object of study and fierce controversy, considered foolish hallucinations of an "inventor" who believed he had uncovered "Aladdin's lamp . The newspapers of carefully followed the career of a man so humble and smart, and often tried to downplay his statements in an attempt to discredit scientific theories too revolutionary, that would seriously compromise the economic world order in those years was to form. Tesla, however, was not to be involved with the media propaganda, and intelligence was able to keep up with the misinformation, without grasping and explaining with extreme provocation ease his mind. So, 19 April 1908, responding to the editorial staff of The New York Times, seeking to clarify certain concepts that were apparently misunderstood. The New York Times, 21 April 1908, will report its replication in an article intolerance " How the Electrician's Lamp of Aladdin May Construct New Worlds ", as if to ridicolarizzare the futuristic vision of the scientist Nikola Tesla.
" When I spoke of future warfare, I meant that you can use direct electrical waves without the use of aircraft or other implements of destruction. This means, as I have already pointed out, that would be ideal not only for energy use in conflicts without any effort for the maintenance of its potential, but it would be essential in times of peace. This is not a dream. Even now, could be built wireless power plants all over the world, without subjecting the population to danger . "This is what he writes in response to the provocations of Nikola Tesla New York Times - published in a note dated 11 March 1908 - thus foreshadowing what is our near future, when there will be " electromagnetic warfare," and the introduction of what is called WiTricity . In fact, his visions are not, but a clear anticipation of technological developments, whereas he knew that the forces existing in the Earth and the universe would be used sooner or later man. For this reason, calls himself a "man of science" and not "an inventor, because the energy already exists in nature, do not invent it but to bring light into its full potential.
" What I have said with reference to the greatest achievement of the scientist, whose mind is once the domain of the physical universe, is nothing more than what I said in one of my publications unpublished " One theory is adopted, each atom is measurably different from a tenuous fluid, that fills the space with a circular motion like a vortex of water in a calm lake. By moving this fluid, the ether, becomes the subject. Stopped its movement, the primary substance reverts to its normal state. So, it seems possible for man, imprisoned by the energy of the medium and the appropriate agents, operate or stop the motion of the ether causing the formation or disappearance of matter. At his command, the old worlds would vanish almost without any effort on his part, and the new would be to exist. The man could change the mass of this planet, control the seasons, change its distance from the sun, guide it on its eternal journey along any path that decides to click through the depths of the universe. Could result in collision planets might create suns and stars, his heat and light, could originate life in all its infinite forms. Generate, at will, birth and death of matter would be the greatest act of man that would give the domain of physical creation, making possible the realization of its ultimate . "
Nothing could be further from the I thought that to call wireless telephony around the world, "the greatest achievement of humanity", as reported. This is an act that, wonderful in every case, the reader can easily be achieved by each expert. I myself have built a facility for this purpose. The wireless is only the beginning, not the result of an extraordinary ability as people think. The truth is that "the electrician has been given a real Aladdin's lamp. All you have to do is wipe it. Now, rub the Aladdin's lamp is not a discovery. "If you are eager to accelerate the achievement of a discovery even bigger and higher, you can oppose with all your might to all the power he intended to interfere with the commercial exploitation and free Water Power and the art of wireless. So human progress depends only on the development of these, and the smallest obstacle, perhaps due to legislative structures this country can bring back the civilization back and undermine peace for centuries .
The clear and shocking revelations of Tesla, however, were not understood then, nor from the world of science or of industry, who preferred to establish his theories of mere "hallucinations of a visionary." Perhaps only now - though still with many difficulties - we can understand the deep meaning of the words of this scientist, who sought only to explain to mankind that the evolution of our civilization could not have been Thanks to science, "free and independent", which must reflect the needs of the human universe, and not for some.
(from http://etleboro.blogspot.com/)
Tuesday, April 29, 2008
Getting Rid Of Brazilian Whiteheads
The (magical) Rubens tube.
<< ...Nel 1922 nel laboratorio della National Electric Light di Cleveland nello stato dell'Ohio [715] , Ernest Fox Nichols, director of laboratory research and his assistant James de Graff obtained with a Tear electrical oscillator special reduced size of very short radio waves of 220 u, shorter than the radiation emitted by a mercury lamp dall'incandescenza-quartz and obtained some years earlier by Heinrich Rubens and Otto von Baeyer [716] .
<< ...Nel 1922 nel laboratorio della National Electric Light di Cleveland nello stato dell'Ohio [715] , Ernest Fox Nichols, director of laboratory research and his assistant James de Graff obtained with a Tear electrical oscillator special reduced size of very short radio waves of 220 u, shorter than the radiation emitted by a mercury lamp dall'incandescenza-quartz and obtained some years earlier by Heinrich Rubens and Otto von Baeyer [716] .
In scientific literature the experiment of 1922 is cited as the definitive test of the electromagnetic nature of the infrared radiation. Such a statement may be ambiguous if it is specified that the experiment, far from being an isolated experiment [717] , insert it into an intensive research elettromagntisti of the late nineteenth century, which aims not only to check the conclusions of the theory of Maxwell but also to inspect the conditions of propagation of electromagnetic waves according to the different frequency bands. The verification of elettromagneticca nature of radiant heat that is not a result of this research, and certainly not the only, let alone the final. The experiment of 1922 was used primarily to fill the region of Hertzian waves and infrared waves, and finally get a continuous transition from light visible to electromagnetic waves. ...>> Taken from ELECTROMAGNETIC NATURE OF THE EXPERIMENT OF RADIANT HEAT 1922
Saturday, April 26, 2008
Employment Contract Commission
BERLUSCONI GOVERNMENT / CASTLES IN THE JUSTICE OR VITO TO PREVENT AND TRICKS pilot process
For approval of a reform that will abolish the discretion in the appointment of judges by annulment
and for a serious change in the bankruptcy law
the referees and the abuses that often appear as real coup attempts of a gray rope of frustrated judges who cover each other, claiming far more energetic measures, although necessary and appropriate separation of the careers and personalities of lawyers who may be affected by the concern of having to pull back to the profession ministerial term of office or the judges who would not have sufficient autonomy the order of belonging and the spirit of caste and fellowship. Among the names circulating, the most qualified for biography and history of consistent struggles for neutrality, impartiality and independence of the judiciary by internal factions and also because they are neither judges nor lawyers, are those of the breast. And Mr Roberto Castelli. Elio Vito. That, however, should include among their advisors, and experts are also those, please forgive the presumption el'autocandidatura, like myself, was tried and acquitted twenty-six times "because the facts did not" taken under house arrest twice for insulting a magistrate at the hearing and to public officials, waived the requirement for twice in the amnesty process and concluded, again, with the broader formula of absolution. I think that could be proven wrong - even as Prime Minister Berlusconi and sen. Castelli has so far done so, you probably do not realize that some dirty robes can be reached do the following I will mention - even those judges who try to write comedies sull'inattuato pre-established principle of the natural judge, by failing to say that the breach of that principle is not, in fact, sanctioned, so it can control the head of the procedures and processes at will, assigning them to colleagues who believes "more reliable "and that can assure the desired result, perhaps to encourage friends or friends of friends. But there is more. It has reached the point of processing, as has happened to the writer, even for interruption of public service, who, by submitting an application for recusal of the judge who does not feel natural, judging from what purports to be prescribed in the tariff approved by the CSM. Although this process is, of course, ended with an acquittal and the image of intimidation directed to the undersigned who had dared to contest the disqualification criteria for allocation of cases. Without saying, then, that some judges have come up with measures even more dangerous and "effectiveness" of the arrests and antagonists to block the protesters. Are sales of goods and judgments of bankruptcy issued, even against people who are creditors of those who submitted petitions in bankruptcy. They're back, in short, the Special Tibunali and confiscations of assets of opponents, which measures the totalitarian regimes and dictators have used and use to survive and props. Of all this I can provide ample evidence. The experiences and investigations made by me are available to the new Premier and new Minister of Justice, hoping that before that amount of arbitrators, document established, are to avoid hampering a serious reform of the justice even by the Magistrates the most serious and who do not use the jurisdiction to private interests or to make, as unfortunately sometimes happens, the market. Mr. Vito person is experienced and has assets courageous battles for the realization of true democracy carried out for decades, even within the Radical Party. At sen. Castles are not lacking tenacity and good will, but can not believe that its reform is effective only because many judges pretend to criticize it, actually to see it approved as a lesser evil. The reform, as stated above, the state sufficient to prevent the abuse of certain judges and magistrates, must be supplemented by rules, specifically, prohibiting the heads of to assign at will and provide for sanctions of nullity proceedings for violations. The only way to ensure that processes are controlled and that the Judiciary
, then, to be used as a bogeyman to the judgments of failure, so serious and urgent reform the bankruptcy law, providing that the bankruptcy order can be imposed only if the applicant proves that the failure of his claim was proven through a final judicial decision and if he tried, always with a sure and definitive way, that the debtor's assets is not large.
Luigi Di Napoli, president of the Movement Democratic Lawyers
luigidinapoli.blogspot.com
luigidinapoli5@libero.it
Monday, April 14, 2008
Genital Herpes Outbreak And Exercise
Tuesday, April 1, 2008
November 2010 Mls Open Tryouts
GALILEO AND THE PRINCIPLE OF RELATIVITY '
In his "Dialogue concerning the system" Galileo Galilei gives a very clear description of the "principle of relativity Galilean. " He imagines an experimenter, who was imprisoned in the hold of a ship, running a series of observations on falling bodies. Galileo explains, very clearly, as in any way possible to make this observation any indication on the speed of motion (uniform) of the vessel by experiments that take place exclusively inside. The Galileo's original formulation, however, is descriptive and marks the entrance of the concept in modern physics of relativity: "It 's impossible to bring out the absolute motion of an object and you can only talk about relative speed of two objects." The principle of relativity is verifiable in the life of every day, sitting in the compartment of a train is leaving the station with another train on the side, we find it hard to understand if we are moving us or the other train. Galilean relativity is in perfect agreement with the mechanics of Newton and the law of universal gravitation. It is therefore not possible to determine the state of absolute motion by measuring the gravitational force between bodies. The relativistic world can be encoded by an infinite number of potential observers, called inertial, and in relative uniform motion. None of these takes precedence over others and the laws of physics are written in the same way for everyone. In special relativity observers are not allowed in non-uniform motion and would indeed be possible to detect the motion of the ship in rough seas. The existence of observers Inertia is an empirical fact and when it does not follow from any higher principle. The Galilean relativity has remained in good agreement with the observed data until the end of the nineteenth century, and continues to be used successfully to treat relativistic phenomena, namely those that take place at speeds much lower than that of light (c = 299,792.458 km / s). At speeds approaching ac - called relativistic - it proves to be invalid and need to use Einstein's relativity.
The Galilean principle of relativity states then the absolute physical equivalence of all inertial reference systems: no experiment performed within a given reference system can highlight the rectilinear uniform and the same system, or, in other words, the physical laws discovered by investigators working in laboratories in uniform rectilinear relative motion must have the same shape. The challenge now is to derive formulas that link the time-space coordinates of the same event viewed from two different references, and to prove that the laws of physics are invariant in form, the transition from a reference to another, it is a question of translating formulas in the content of this principle. Consider two references in order (ie, two systems of orthogonal axes):
Galilean relativity is perfectly valid to explain the covariance of mechanical laws of nature in the transition from an inertial system to another, fell into default when you consider the phenomena of electromagnetic nature. These phenomena are summarized in qualitative terms, the following laws:
1. Coulomb's law (the electric field of a point charge);
2. The magnetic field lines are continuous and have no beginning or end;
3. A time-varying magnetic field produces an electric field (electromagnetic induction);
4. A magnetic field can be produced by a flow of current from a variable electric field.
Well, the equations that govern these phenomena - the equations of Maxwell (James Clerk Maxwell, 1831-1879) - are not covariant with respect the Galilean transformations: if they were universally valid, an inertial observer who performs an experiment of electromagnetic nature, would notice and be at rest or in motion with respect to another inertial observer, depending on the outcome of a similar experiment, conducted by this second observer.
RELATIVITY 'Einstein
The Galilean transformations ensure the covariance of physical laws, the variation of inertial systems, only with regard to mechanical phenomena, but they fall in default when you take into account the phenomena of nature Electromagnetic. Is due to Albert Einstein (1879-1955) a considerable extension of the formulas of Galileo, which ensures the covariance of all physical laws, the variation of inertial systems. Suppose, next to each other, the formulas of Galileo and Einstein, to examine the similarities and differences. We refer to the figure of Part 1 , assuming, for simplicity, that the relative motion of the two systems occurs in the direction of x, common to both.
Einstein Galileo
formulas down (Galilean transformations), in which the spatial coordinates are strictly independent of time, involve that the two observers, moving relative to each other, have synchronized clocks. The formulas above (Lorentz transformations, which were adopted by Einstein), in which the spatial coordinates and the time they imply one another, imply that the two observers, moving relative to each other, have asynchronous clocks. The Lorentz transformations give good results, whenever the velocity v with which a system moves to the other, c is comparable to that of light - about 300,000 miles per second - while, as noted immediately, if the relationship is negligible, is reduced substantially to those of Galileo. The speed of light, and any other electromagnetic phenomenon, are to varying covariates inertial systems, like the mechanical laws of nature, if we assume as valid the Lorentz transformations.
In 1916, Einstein extended the principle of relativity to all reference systems, including non-inertial, using formulas that guarantee the covariance of all the laws of nature, the variation of observers (General Relativity). In particular, every observer measures in its own space-time (generally non-Euclidean), the distance between two events in space-time, using a metric whose coefficients are functions of the distribution of matter and energy in space itself. This implies that space and time are no longer, as Newton , two empty containers, where you can admire the natural phenomena, but a construction of the same phenomena (see Descartes ). Gravitational effects, such as tides , find place in this beautiful theoretical construction, which remain valid, with some correction, but the formula Newton . But it is to be noted that this formula, in the context of general relativity, does not express ghostly action at a distance, but spontaneous movements or natural LINEEA along the minimum length (geodesic) space-time. According to the evocative words of Max Jammer (contained in History of the concept of space ): "[...] the gravitation does not own, in General Relativity, the characteristics of a force, but reduces to a property of space-time. The program Descartes (ie the geometrization of physics), has finally been realized by Einstein. " One might add that the validity in this context, the formula for gravitational Newton produce also, somehow, a synthesis of Cartesian ideas and those of Newton himself.
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