Tardigrades, also known as the water bear, are microscopic animals , which can survive in many extreme conditions , including space . ( Taylor Turner/The Washington Post )
Tardigrades have a reputation as the toughest animals on the planet. Some of these microscopic invertebrates shrug off temperatures of minus 272 Celsius , one degree warmer than absolute zero. Other species can endure powerful radiation and the vacuum of space. In 2007, the European Space Agency sent 3 ,000 animals into low Earth orbit , where the tardigrades survived for 12 days on the outside of the capsule.
To a group of theoretical physicists , tardigrades were the