What would exactly happen to the crew of a spacecraft traveling at 99.999998 per cent the speed of light? William Edelstein, at the Johns Hopkins University School of Medicine in Baltimore, Maryland, has the answer: It'd hurt. A lot.
Using Einstein's special theory of relativity, Edestein—an expert in radiology—concluded that astronauts will die instantly from radiation overload, thanks to the kinetic energy of the atoms surrounding the ship. The hydrogen atoms floating in the empty space would reach 7 teraelectron volts, which is the equivalent of staying at the center of the Large Hadron Collider set at maximum power. Even with a 10-centimeter-thick aluminum hull, 99 per cent of the energy will pass, destroying humans and circuitry inside.