eli5 how do we know nothing is faster than light?
In: 452
Astronomers noticed that the speed of moons going around planets seemed to change depending on whether the Earth was moving towards or away from them. Well, that didn’t make sense, how would they know and why would Earth affect them, so they thought, what if the light was taking longer to reach our eye as we moved away, and less time as we got closer — something that would be true if light had a speed.
Over the next 250 years, we measured stuff and worked out the math of how stuff like gravity behaved. A guy named Einstein summed up a lot of what we had worked out as math, and noticed that you could rearrange the equation in a way where the speed of light never changed, but instead things like time and the mass of things changed when they moved fast.
That sounds crazy, but we worked out ways to test Einstein’s theories, and we’ve always shown that he is right.
I turns our that there’s a simple equation that describes how much time slows or mass increases as something moves very fast. It turns out that the equation doesn’t have solutions when the speed of something is equal to or faster than the speed of light. We don’t have a way to test what happens if we could speed something up beyond the speed of light, but we’ve also never seen anything moving faster either.
We presume nothing moves faster than light because our math and observations tell us that it can’t.
Latest Answers