We have all seen the famous equation E = mc² devised by the German physicist Albert Einstein and enunciated in 1905, as part of the Theory of Relativity, specifically on the equivalence between mass and energy, however, despite its countless applications in science, this equation that we have been taught since childhood, is not totally correct, or at least, incomplete...
According to the equation E = mc², Energy (E) is equal to Mass (m) by the speed of light (c, with a value of 3 × 10⁸ m / s or 299792458 m / s, rounded 300 million m / s) square, but if we are strictly guided by these values, what would happen to an object at rest, without any movement? or most notoriously, what about an object without mass? If we take for example particles of light (photons), which have no mass, the equation would result 0, and therefore the light would have no energy, and we know that this is not correct, therefore we have reached the point where E = mc² seems to be incorrect and the fact is that it is not complete.
Actually, it is a historical error, Einstein enunciated the theory correctly, and E = mc² is a very shortened and limited version, which however became very popular and has come to present day, however the correct and complete formula is:
E² = (mc²) ² + (pc) ²
where p is the moment of the particle in the equation. The moment is, in essence, a measure of speed. In the case of photons, they have no mass but they do have momentum, that is, they are moving. The fact that E is squared means that you have to take the square root to find the solution. But, mathematics tells us that when we calculate square roots we will always get two solutions, one positive and one negative. For example, if we have two solutions, let´s say 2 and -2, this is because 2² = 4 and (-2) ² = 4 as well; however, this does not mean that there can be negative energy, the answer is more complex and it is attributed to the British theoretical physicist and engineer Paul Dirac who in 1931 interpreted the negative energies as the antiparticles, in this way all the particles (charged) have an antiparticle associated, the proton has its antiproton, the electron its antielectron or positron, etc. |
| Albert Einstein (1879 - 1955) |
Then, it is concluded that the formula E = mc² is only correct in objects without movement and obviously with mass, and although it was fundamental for the fusion of uranium in the creation of the nuclear bomb, that does not mean that E = mc² is not used in today´s world: in fact it has several applications, but restricted to objects with mass and movement, and is valid only in the context of special relativity, but not in that of general relativity.
Josher
January 27, 2019
al cuadrado, pero si nos guiamos estrictamente por esos valores, ¿qué pasaría con un objeto en reposo? o lo más notorio aún ¿qué pasa con un objeto sin masa? Si tomamos por ejemplo partículas de luz (fotones), al no poseer masa, la ecuación daría 0, y por lo tanto entonces la luz no tendría energía, y sabemos que eso no es correcto, por tanto hemos llegado al punto donde E=mc² no es completa.
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