When most people think of Einstein and special relativity, they think of the equation E = mc² . What does this mean? E = mc² is basically a conversion equation between mass (m) and energy (E) where c is the speed of light. By looking at this, we can see that a little mass goes a long way toward creating energy because c² is extremely large. The atomic bomb illustrates this principle perfectly. Perhaps in the future we can use our vast supply of seawater to provide the whole world with energy using fusion power plants.

E = mc² is also relevant to our discussion of the speed of light limit. Since speed parallels energy, as something increases in speed it increases in mass as well. Take muons as an example again. At 99.99999999% the speed of light, the mass of a muon is increased by a factor of 70,000. It is, of course, much more difficult to move something that is very heavy than it is to move something light. The mass of an object approaches infinity as its speed approaches that of light. Therefore, it would take an infinite amount of energy to break the light barrier.