The NASA Announcement: A New Form of Life? Maybe!

by Ann Finkbeiner

After several days of hoo-ha brought on by a vague NASA press release about mysterious life forms that will change how we see alien life, the story finally was published in Science and announced by NASA and so, okay, I’ll bite. It turns out that a geomicrobiologist found a bacterium in a California lake full of arsenic, and the bacterium was full of arsenic too. The arsenic atoms were being used by the bug in place of phosphate atoms; and if you’d paid attention back when you were supposed to, you’d know that phosphate atoms are crucial to 1) DNA which is the molecule that makes up genes; and 2) ATP which is the molecule that provides cells’ energy. So: genes and energy, about as basic as you’d want to get.

NASA says life forms based on arsenic are so biochemically different from every other life form on earth that maybe they could exist on other planets. Biochemists say sure, of course, but first let’s find out whether those bugs are actually using the arsenic and not just co-existing with it since they live in an arsenic-filled lake.

Apparently the bugs still like their phosphates and New York Times quotes a kindly biochemist saying they were clinging to every last phosphate “and really living on the edge.” He said he felt sorry for them.

The last time NASA discovered extraterrestrial life, it was bacteria in a meteorite that had come from Mars; and months later, with no press releases, the bacteria turn out to be contamination from the site where the meteorite was found.

Never mind, the arsenical bug is at least another interesting extremophile. For the time being I’m going to grant NASA this one.

Ann Finkbeiner is the coproprietor of The Last Word on Nothing.