Meet the Tardigrades: The Solar System's Most Extreme Survivors

There is an organism living on this planet who can travel through space without a suit. Cute, unassuming little invertebrates, these organisms are called tardigrades, or water bears, and usually spend their days crawling around on a piece of nice wet moss in a forest, or meandering through our vast oceans. They only grow to be about 1.5 millimeters long, but over 1,000 species of them inhabit the planet, and they all have a superpower unmatched by any other species on Earth. No now knows why, but tardigrades can withstand temperatures as cold as liquid nitrogen, radiation doses that would kill a human 100 times over, thrive in an outer-space-like vacuum, and survive without water for years. More »