# Einstein and Lorentz

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1. Jan 5, 2015

### Jorlack

I am hoping someone can help me with something. I want to go into the field of temporal physics and I was wondering if someone could help me understand why Einstein's E=mc2 isn't combined with Lorentz's factor ϒ=1/√1-(v2/c2) to further prove the light-speed barrier?

2. Jan 5, 2015

### Staff: Mentor

Both of these relationships are derived from the same underlying assumptions (the two postulates of special relativity - Google for "On the electrodynamics of moving bodies" to find Einstein's 1905 paper on SR) as the light-speed limit. Thus, using them to "further prove" the lightspeed limit doesn't tell us anything new; it just shows that the assumptions that lead to the light-speed limit lead to the light-speed limit.

3. Jan 6, 2015

### ChrisVer

Also the relation $E=mc^2$ is already given at a certain Reference fram (the rest frame of the object of mass $m$ ). So how would you put a gamma factor?

4. Jan 6, 2015

### Jorlack

T
Thank you for the reference, Nugatory. Also, could you recomend any books or sights that are credited and discus the possibility of Tachyons?

5. Jan 6, 2015

### Khashishi

Jorlack, you are right. One way of writing the energy equation is
$E=\gamma m c^2$
The common equation $E=mc^2$ is only valid for particles at rest, when $\gamma = 1$.

6. Jan 7, 2015

### Jorlack

$\gamma = 1$ when the velocity of the said object or particle is 0. Therefore the Lorentz factor would equal $1/1$ or simply, 1.