Question: is light the ultimate speed limit or can things travel faster

Edward Bovill answered on 13 Mar 2013:

With our current understanding of physics, the speed of light is the fastest that anything can travel in the universe. However, depending on what light is travelling through, it goes at very different speeds. The speed of light most people think of (300,000km per second) is how fast light travels in the vacuum of space. In air it is slightly slower and in diamond it travels at half the speed. Scientists have even managed to slow light down to walking pace in some materials!

There is one type of particle, that is currently only a theory, called the tachyon that travels faster than the speed of light. Because of this, they would travel backwards in time and pose all kinds of problems with the way we think the universe works. No-one has found any proof that they exist though, so we physicists have nothing to worry about quite yet.