According to Einstein's theories of relativity
this is indeed the case.

Before Einstein came along, such laws of kinetics were based on Newtonian dynamics, which were derived from everyday observations. It was impossible to prove them wrong and no-one thought there should be any reason for them to be wrong. But Einstein showed that Newtonian dynamics were only a low energy approximation to the 'correct' theory. At high energies, like particles travelling at close to the speed of light, it all goes out the window.

Now, we've tested relativity pretty thoroughly, and it's always been right so far. But that's not to say that we won't be able to come up with other theories in future, which may or may not be testable, which allow for faster-than-light (FTL) travel.

In fact, some people already have come up with this sort of thing. Google 'tacheon'.
( K2k6 has a proper job these days, Thu 22 Oct 2009, 13:31, 2 replies, latest was 16 years ago)

Ah, yes, I've heard about these tachyon types
Not to discount it, I'm sure it's a perfectly valid theory rather than just a quirk of the maths (after all, that's how we first discovered antimatter) but someone is going to need to come up with a way to test that theory...
(LongJohnBaldry, Thu 22 Oct 2009, 13:33, Reply)

It's even out of the league
of the LHC boys at CERN. I think they'd need to harness the power of a whole star and build an interplanetary accelerator to do that!

And you're right - it's tachyon, not tacheon. My mistake.
( K2k6 has a proper job these days, Thu 22 Oct 2009, 13:35, Reply)

The whole tachyon thing
Is totally allowed in GR, it means that they must always be travelling faster then c just as all us slow-coaches must always travel slower than c.
(Shippy likes linebreaks and doesn't care what you think, Thu 22 Oct 2009, 14:17, Reply)