December 4, 2010
A scanning-electron micrograph image of arsenic-eating bacteria. (Science/AAAS)
Kids are asking a lot of questions this week. Like: What is all this talk about alien life being discovered? And: Why is NASA making the announcement, when the discovery is in California, not in space? Kids (and many adults) are wondering why this is such a big deal.
The simple answer is that we always thought there were six elements essential to all life as we know it till now: carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur. As we send probes to search the solar system looking for signs of life, we have been looking for the presence of these elements (including water, which is a combination of hydrogen and oxygen, or H2O). Now, researchers have discovered microbes in a hostile environment called Mono Lake, which replace phosophorus with arsenic. If the claim holds up, it would support the idea that life as we know it isn’t the only way life could develop.
Felisa Wolfe-Simon (no relation), is an astrobiology researcher who originally proposed the theory, and she co-authored the paper that caused all the excitement this week. "If something here on Earth can do something so unexpected, what else can life do that we haven’t seen yet?" she asked. "Now is the time to find out."
If life is more adaptable than we previously thought, then it expands the possibilities for places that we might find life beyond Earth. That, in a nutshell, is what this week’s excitement is all about.
Mono Lake, 13 miles east of Yosemite National Park.
Posted by: Seymour Simon
