Scientists, writing in today’s edition of the journal Science, recommend that the search for extraterrestrial life be rejiggered. Instead of focusing on planets around other stars, researchers should look instead for bacterial life on a hypothetical planetorbiting a faraway star.
It’s a relatively radical suggestion, but still understandable given that the first planet discovered to have a resident bacterial lifeform is a strange gaseous world known as Gliese 667Cc, which was found in 2009. Scientists detected the bacterial life this life called cyanobacteria.
“If you go back to when the first was discovered, no one was ready to think that there might be cyanobacteria on a planet,” said David Ropeik, who is a co-author of the paper. “It made me wonder, would that human discovery on Gliese 667Cc have the same significance had it been found on a planet like Earth. Or is it possible that if the first was discovered in a planet, the next one could be discovered in a star?”
The reason the implications of this transition are so crucial is because the chemical composition of a planet and its star are relatively predictable. Thus if a certain chemical signature that a planet has, how it gets there can be predicted with some accuracy. However, that isn’t the case for a star, which gets altered by its own constant fluctuations in it’s magnetic field. With this in mind, NASA is sponsoring a multi-university astrobiology research program called the Saturn IB program.
Ropeik, who is with Johns Hopkins University’s Applied Physics Laboratory, said that planetary researchers are changing their focus to looking for conditions on planets like Gliese 667Cc, which are not our solar system’s sun.
“At present, we know that life on Earth must be linked to a planet, otherwise why should it exist on Earth?” he said. “Only by studying space-born life can we learn whether it could have formed on a star like our Sun.”
This is a rather attractive argument: We know how to find alien life, so why not just start looking? However, James Asher, a computational astrobiologist at the University of Washington, thinks that this shift away from finding planets around other stars is doomed to failure.
“The notion that a planet where life is abundant could somehow have life on a star like our Sun makes sense if you think that we have the tools needed to detect alien life on a star just like the Sun,” he wrote in an email. “But this is a really harsh analogy because this would require spotting Mars-like rocks or liquid water on Mars. Such specific samples are certainly extremely unlikely.”