The Washington Post has an advance peek at the big announcement NASA has scheduled for later today. It’s not aliens, but it is pretty interesting nonetheless — researchers have found a bacterium that relies on arsenic, not phosphorus, as one of its six essential components.
The Post said this doesn’t prove that some forms of life on Earth evolved from a different common ancestor than the rest of us — the so-called “second genesis.” “But the discovery very much opens the door to that possibility, and to the related existence of a theorized ‘shadow biosphere’ on earth.”
The Mono Lake discovery highlights one of the central challenges of astrobiology — knowing what to look for in terms of extraterrestrial life. While it remains uncertain whether the lake’s microbes represent another line of life, they show that organisms can have a chemical architecture different from what is currently understood to be possible.
“One of the guiding principles in the search for life on other planets, and of our astrobiology program, is that we should ‘follow the elements,'” said Ariel Anbar, an ASU professor and biogeochemist. [Biochemist and researcher] “Felisa [Wolfe-Simon]’s study teaches us that we ought to think harder about which elements to follow.”