New discovery is not "alien"

The announcement today from NASA that they had discovered a form of life that uses arsenic rather than phosphorus has many implications for the search for extraterrestrial life. Scientists don't have to limit their search to areas that only have carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur now. It's at least as important as the discovery of archaea in the 1970s.

But I think the significance of the discovery has been somewhat misconstrued as well, especially leading up to the announcement. The life form Felisa Wolfe-Simon discovered, called GFAJ-1, is not an entirely new form of life. It's a branch of life as we know it. In fact, it is a bacteria. But it's a form of life which has evolved the ability to swap potassium for arsenic. It's a weird form of life, but it is still descended from the last universal ancestor, the parent of every living thing we see around us.

So to say it's an alien form of life is wrong. But it has profound implications in the search for alien life in places other than earth, since it expands the concept of what we mean when we say "life".

This story is not about Mono Lake or arsenic, she said, but about “cracking open the door and finding that what we think are fixed constants of life are not.”

I would say this has few if any implications for the search for extraterrestrial intelligence, since if we find intelligence in the universe, it will likely not even be biologically based.