Speaking of rapid aging, a new study found that just six months on the International Space Station caused super-fast deterioration in astronauts' muscles, leaving them as weak as people twice their age. According to the Associated Press, "the accelerated space aging is temporary: Astronauts' muscles recover after a few months back on Earth." But the findings, based on calf-muscle biopsies on Russian astronauts who were living on the ISS from 2002 to 2005, are worrying for the future of deep-space exploration in general. The worst deterioriation happened in the slow-twitch muscle fibers, which are crucial for balance and posture, and the strongest weightlifting astronauts were the hardest hit. [Associated Press]