On my daily slog through science websites I’ve come across several articles about microscopic animals called water bears, technically known as tardigrades. They’ve been in the news a lot lately because a recent experiment in space has shown that water bears are among the few living things that can survive direct exposure to the vacuum of space and to the sun’s ultraviolet radiation. Check out this article to learn more about the experiment.
Anyhow, this made me curious about water bears, and so I did a little research. Here’s what I learned:
–First, water bears are cute. Up close (as in through a microscope), the creatures do sort of resemble tiny bears. They have four legs and two arm-like appendages with what look like little claws. And when they move, water bears lumber around a bit like grizzly bears. (You can watch a movie of water bears in action here. (Apparently, according to this website, water bears were first named as such in 1773 by John August Ephraim Goeze, a German pastor.)
–There are at least 700 species of water bear, most of which are about half a millimeter long.
–The coolest thing about the water bear is that it’s able to survive extreme conditions by going into a state of suspended animation. Essentially, water bears can dry up and survive for years without water and be carried around on the wind. When they do come into contact with water, water bears revive and get on with their lives as though nothing happened.
The discovery that water bears can survive in space has been taken by some scientists as evidence that life arrived on Earth from space. This article, in the Sri Lanka “Daily News,” paraphrases one Professor Chandra Wickramasinghe to the effect that insects may have originated in space and been brought to earth by comets.
Whether or not that’s the case, water bears are an intriguing example of just how resilient life can be.
The claim that they came from space is way out there… thousands of DNA sequences suggest they’re bona fide earthlings.
Earth was uninhabitable in it’s infancy, and I imagine things did not just magically appear. The building blocks for what is around us had to come from somewhere. Where else except space?
Stephanie
The obvious response to your question is two-fold. 1. How do you KNOW Earth was uninhabitable in its infancy? 2. If the ‘building blocks’ had to come from SOMEWHERE, why not Earth? I agree that they “did not just magically appear” - but I think you know what my ’solution’ would be!
Stephanie
How do you KNOW that Earth was uninhabitable in its “infancy”? Also, Earth itself is actually IN “space”, so why would you assume that the “building blocks” were extra-terrestrial? I fully agree with you that “things did not just magically appear” - but I am guessing that you really DO know what MY solution is!