# Is the current view of the intergalactic speed limit short sighted?

## Main Question or Discussion Point

Is the current view of the intergalactic "speed limit" short sighted?

Just a question that may have some enlightening answers....
Einstein says that the interstellar speed limit is the speed of light. What happened to E=MC2?
If mass doesn't convert to energy till accelerated to the square of the speed of light, would it not follow that the increase in mass occurs as it approaches the square of the speed of light, rather than the speed of light? If this were true, then faster than light drives should be able to go many times the speed of light up to approaching the square of the speed of light.
Just a question that may have some enlightening answers....

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I think you're misunderstanding Einstein's energy equation. Who told you mass doesn't convert to energy unless it reaches the speed of light squared? That equation is a statement of the amount of internal energy an object has at a given mass. When combined with other relativistic equations, such as energy and momentum conservation, this equation allows mass to be converted to energy and vice versa. One example of this is pair production.

Also, there is no increase of mass as the massive object accelerates. When a massive object approaches the speed of light, its energy approaches infinity (E = mγc2) and its momentum approaches infinity (p = mγv) but its mass is invariant under Lorentz transformation. You were probably taught that an objects "relativistic mass" increases to infinity (M = γm, such that E = Mc2) but this is an outdated notion, and doesn't really help our understanding of special relativity as much as it hinders it.

The only thing special about the speed of light SQUARED is that it is the scaling factor in translating between the MASS and object has and the REST ENERGY it has. This E = mc2 equation holds no information about the universal speed limit, or what happens to E, p, or m when you approach it. It also doesn't tell you what speeds need to be reached before mass can be transformed to energy, or vice-versa. It is simply a statement of rest energy. You need to dive more into the other equations of special relativity, Lorentz transformation and Minkowski space to understand more than what this flashy equation gives you.