Interstellar hydrogen would be lethal for warp drive travellers

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".

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."

Kinda makes you have whole new appreciation for them forward shields on the U.S.S. Enterprise, aye? :-)