Tardigrades, also know as Water Bears or Moss Piglets, are a microscopic animal can be found in every continent on Earth. They usually live in aquatic habitats. However, some incredible things can happen when they are taken out of water.
Tardigrades can be in a state of being called "tun" form, a dormant state in which they shrivel into a ball, expel most of the water from their bodies and lower their metabolism until their environment is more sustainable for life. They can exist like this for decades.
They are very hardy and can live through extremely tough environments, including subzero temperatures.
Tardigrades could live through extreme pressures, like the pressure of an asteroid hitting the Earth. Recent tests have shone that they could withstand 5 times the vacuum and pressure of the deepest ocean.
When a tardigrade enters the "tun" state, it doesn't age. It can become dormant at one-month old, and wake up years later the same age.
It was discovered in 2007 that these creatures can withstand the vacuum of space! In fact, they might be aliens.
Without being in the "tun" state, the average life-span of a tardigrade is only a few months.
They can also withstand the kind of radiation found in space which usually rips apart molecules and damages DNA faster than it can repair itself. This radiation comes from suns, supernovae and other sources.
They are the first animal we know of capable of withstanding space's vacuum.