AP Photo

One hears epic accounts of people surviving bullets to the brain, 10-story freefalls or months stranded at sea. But put a human anywhere in the known universe except for the thin shell of space that extends a couple of miles above or below sea level on Earth, and we perish within minutes. As strong and resilient as the human body seems in some situations, considered in the context of the cosmos as a whole, it's unnervingly fragile.