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| | For more than a century, the claim that '''E=mc²''' has never yielded anything of value. Often it seems to be used as a redefinition of "[[energy]]" for pseudo-scientific purposes, as by the [[lamestream media]]. There have been attempts to find some justification for the equation in already understood processes involved in [[nuclear power]] generation and [[nuclear weapon]]s, and in the speculation about [[antimatter]].<ref>Tyson, Peter. "The Legacy of E=mc²." October 11, 2005. PBS ''NOVA''. http://www.pbs.org/wgbh/nova/physics/legacy-of-e-equals-mc2.html</ref> | | For more than a century, the claim that '''E=mc²''' has never yielded anything of value. Often it seems to be used as a redefinition of "[[energy]]" for pseudo-scientific purposes, as by the [[lamestream media]]. There have been attempts to find some justification for the equation in already understood processes involved in [[nuclear power]] generation and [[nuclear weapon]]s, and in the speculation about [[antimatter]].<ref>Tyson, Peter. "The Legacy of E=mc²." October 11, 2005. PBS ''NOVA''. http://www.pbs.org/wgbh/nova/physics/legacy-of-e-equals-mc2.html</ref> |
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| − | The [[Theory of Relativity]] has never been able to mathematically derive '''E=mc²''' from first principles, and a physicist observed in a peer-reviewed paper published in 2011 that "a rigorous proof of the mass-energy equivalence is probably beyond the purview of the special theory."<ref>http://adsabs.harvard.edu/abs/2011AmJPh..79..591H</ref> | + | The [[Theory of Relativity]] has never been able to mathematically derive '''E=mc²''' from first principles, and a physicist observed in a peer-reviewed paper published in 2011 that "a rigorous proof of the mass-energy equivalence is probably beyond the purview of the special theory."<ref>[http://adsabs.harvard.edu/abs/2011AmJPh..79..591H Eugene Hecht: ''How Einstein confirmed E<sub>0</sub>=mc²'', American Journal of Physics, Volume 79, Issue 6, pp. 591-600 (2011)]</ref> |
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| − | It has been known for a long time that radiation has a mass equivalence, which was correctly derived by [[Henri Poincare]] in 1904,<ref>http://www.opticsinfobase.org/josa/abstract.cfm?uri=josa-42-8-540</ref> but the equation '''E=mc²''' makes a claim far beyond that limited circumstance: | + | It has been known for a long time that radiation has a mass equivalence, which was correctly derived by [[Henri Poincare]] in 1904,<ref>[http://www.opticsinfobase.org/josa/abstract.cfm?uri=josa-42-8-540 Herbert E. Ives ''Derivation of the Mass-Energy Relation'', JOSA, Vol. 42, Issue 8, pp. 540-543 (1952)]</ref> but the equation '''E=mc²''' makes a claim far beyond that limited circumstance: |
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| | {{cquote|The equality of the mass equivalent of radiation to the mass lost by a radiating body is derivable from Poincaré’s momentum of radiation (1900) and his principle of relativity (1904).|||Herbert Ives, 1952}} | | {{cquote|The equality of the mass equivalent of radiation to the mass lost by a radiating body is derivable from Poincaré’s momentum of radiation (1900) and his principle of relativity (1904).|||Herbert Ives, 1952}} |
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| | == Description for the layman == | | == Description for the layman == |
| − | Ten top physicists were asked to describe in laymen's terms '''E=mc²''':<ref>http://www.pbs.org/wgbh/nova/einstein/experts.html</ref>{{cquote|''Things that seem incredibly different can really be manifestations of the same underlying phenomena.''|||Nima Arkani-Hamed, Theoretical Physicist, Harvard University}}{{cquote|''You can get access to parts of nature you have never been able to get access to before.''|||Lene Hau, Experimental Physicist, Harvard University}}{{ | + | Ten top physicists were asked to describe in laymen's terms '''E=mc²''':<ref>[http://www.pbs.org/wgbh/nova/einstein/experts.html Lexi Krock, David Levin (editors) ''E=mc² explained'', June, 2005. PBS ''NOVA'']</ref>{{cquote|''Things that seem incredibly different can really be manifestations of the same underlying phenomena.''|||Nima Arkani-Hamed, Theoretical Physicist, Harvard University}}{{cquote|''You can get access to parts of nature you have never been able to get access to before.''|||Lene Hau, Experimental Physicist, Harvard University}}{{ |
| | cquote|''It certainly is not an equation that reveals all its subtlety in the few symbols that it takes to write down.''|||Brian Greene Theoretical Physicist Columbia University}} | | cquote|''It certainly is not an equation that reveals all its subtlety in the few symbols that it takes to write down.''|||Brian Greene Theoretical Physicist Columbia University}} |
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| | == History of '''E=mc²''' == | | == History of '''E=mc²''' == |
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| − | The [[liberal]] [[Public Broadcasting Service]] explained the history of '''E=mc²''' for its NOVA series as follows:<ref>http://www.pbs.org/wgbh/nova/physics/ancestors-einstein.html</ref> | + | The [[liberal]] [[Public Broadcasting Service]] explained the history of '''E=mc²''' for its NOVA series as follows:<ref>[http://www.pbs.org/wgbh/nova/physics/ancestors-einstein.html David Bodanis ''Ancestors of E=mc²''], NOVA, Nov 10, 2005]</ref> |
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| | {{cquote|Over time, [[physicist]]s became used to multiplying an object's mass by the square of its [[velocity]] (mv²) to come up with a useful indicator of its energy. If the velocity of a ball or rock was 100 mph, then they knew that the energy it carried would be proportional to its mass times 100 squared. If the velocity is raised as high as it could go, to 670 million mph, it's almost as if the ultimate energy an object will contain should be revealed when you look at its mass times c squared, or its mc².}} | | {{cquote|Over time, [[physicist]]s became used to multiplying an object's mass by the square of its [[velocity]] (mv²) to come up with a useful indicator of its energy. If the velocity of a ball or rock was 100 mph, then they knew that the energy it carried would be proportional to its mass times 100 squared. If the velocity is raised as high as it could go, to 670 million mph, it's almost as if the ultimate energy an object will contain should be revealed when you look at its mass times c squared, or its mc².}} |
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| | ==Experimental verification== | | ==Experimental verification== |
| − | The first experimental verification for the equation was performed 1932 by a team of an English and an Irish physicist, John Cockcroft and Ernest Walton, as a byproduct of ''"their pioneer work on the transmutation of atomic nuclei by artificially accelerated atomic particles"''<ref>[http://www.nobelprize.org/nobel_prizes/physics/laureates/1951/# Nobel Prize Organization]</ref> for which they were honored with the [[Nobel Prize]] in physics in 1951. The idea of the mass defect - and its calculation using ''E=mc²'' can be found on page 169-170 of his Nobel lecture.<ref>http://www.nobelprize.org/nobel_prizes/physics/laureates/1951/cockcroft-lecture.pdf</ref> | + | The first experimental verification for the equation was performed 1932 by a team of an English and an Irish physicist, John Cockcroft and Ernest Walton, as a byproduct of ''"their pioneer work on the transmutation of atomic nuclei by artificially accelerated atomic particles"''<ref>[http://www.nobelprize.org/nobel_prizes/physics/laureates/1951/# Nobel Prize Organization]</ref> for which they were honored with the [[Nobel Prize]] in physics in 1951. The idea of the mass defect - and its calculation using ''E=mc²'' can be found on page 169-170 of his Nobel lecture.<ref>[http://www.nobelprize.org/nobel_prizes/physics/laureates/1951/cockcroft-lecture.pdf John D. Cockroft ''Experiments on the interaction of high-speed nucleons with atomic nuclei''], Nobel Lecture, Dec 11, 1951]</ref> |
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| | They bombarded [[Lithium]] atoms with [[protons]] having a [[kinetic energy]] less than 1 [[Electron-Volts|MeV]]. The result were two (slightly less heavy) [[α-particle]]s, for which the [[kinetic energy]] was measured as 17.3 MeV | | They bombarded [[Lithium]] atoms with [[protons]] having a [[kinetic energy]] less than 1 [[Electron-Volts|MeV]]. The result were two (slightly less heavy) [[α-particle]]s, for which the [[kinetic energy]] was measured as 17.3 MeV |