Assuming that we could ever figure out how to travel faster than the speed of light, there may not be a heck of a lot that we could do with it. That's what Professor William Edelstein of the Johns Hopkins University School of Medicine (dude sounds like a polymath for having a good head about medicine and high-energy physics) has determined.
The problem is hydrogen, which exists in interstellar space on average of two atoms per cubic centimeter. Which ain't a whole lot. But if a spacecraft were to accelerate toward lightspeed those scarce atoms would start bombarding the ship like a hail of bullets...
As the spaceship reached 99.999998 per cent of the speed of light, "hydrogen atoms would seem to reach a staggering 7 teraelectron volts", which for the crew "would be like standing in front of the Large Hadron Collider beam".Kinda makes you have whole new appreciation for them forward shields on the U.S.S. Enterprise, aye? :-)
This is a very bad thing, because humans in the path of this ray would receive a dose of ionising radiation of 10,000 sieverts, and as Bones McCoy would doubtless confirm, the lethal dose is 6 sieverts.
The result? Death in one second.
The spacecraft's structure would do little to mitigate the effects of the killer hydrogen. Edelstein "calculates that a 10-centimetre-thick layer of aluminium would absorb less than 1 per cent of the energy", and the intense doses of radiation would damage the ship's structure and fry its electronics.
Edelstein grimly concluded: "Hydrogen atoms are unavoidable space mines."