NASA has discovered a totally new kind of life form, but it’s not an alien—it’s here on Earth. Astrobiologists have found a bacteria living in a poisonous California lake that’s actually partially made of arsenic, it announced in a much-hyped press conference today. Whereas every other organism ever observed is made up of six essential ingredients—carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur—this one seems to have replaced phosphorus with arsenic, the Washington Post explains.
That means the bacteria evolved from a different common ancestor than every other organism on the planet, suggesting the possibility of a “shadow biosphere" here on Earth. The finding could completely change how NASA looks for extraterrestrial life. “Our findings are a reminder that life-as-we-know-it could be much more flexible than we generally assume or can imagine,” says the biochemist who led the research. “If something here on Earth can do something so unexpected, what else can life do that we haven’t seen yet?” (Read more NASA stories.)