Can you say polyextremophile?

Here are two questions about the tardigrade that puzzle most researchers: How could a terrestrial lifeform evolve to survive exposure to the vacuum and high energy radiation of space? Why did tardigrades evolve an ability to survive a century in a kind of dehydrated suspended animation (especially when it already lives in watery environments with no geohistory of drought?)

Were these microscopic creatures, and others like them, exposed to the environment of space in ancient times? Is that why they evolved such extreme environmental survival mechanisms? What evolutionary factors influenced this polyextremophile to endure the extremes of outer space when it appears to have originated here on planet Earth?

There is no clear solution to the tardigrade mystery at this time.

What's in the Sky: The Lyrid meteor shower occurs through April 24, with the peak of activity expected on April 22. Comet Thatcher is the source of the Lyrid meteor shower. An observer can see 10-12 meteors per hour.

Lou Varricchio, M.Sc., is a former senior science writer at the NASA Ames Rsearch Center in California and an active member of NASA's JPL Solar System Ambassador program in Vermont. He is a recent recipient of the U.S. Civil Air Patrol's Maj. Gen. Chuck Yeager Award for Aerospace Education.

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