All of this is to say, rather snarkily, that there probably isn't alien life on comet 67P/Churyumov-Gerasimenko, microbial or otherwise, and that most astrobiologists are pretty ticked off at the media's suggestion that there is.
The hubbub stems from an article published by The Guardian, which cites two "maverick" scientists (what?) who believe that the comet's ice is harboring extremophiles -- the kind of life that lives on the very edge of Earthly habitability, in the deep subterranean lakes of the Arctic and the hellish steam vents at the bottom of the sea.
And the comet, which is being orbited by the European Space Agency's Rosetta spacecraft and poked and prodded by the intrepid Philae lander, is indeed pretty interesting. Scientists have spotted exposed water ice and even actively forming sinkholes, showing that the comet is a dynamic place. But while none of this makes life sound totally impossible on the comet, none of it makes a direct case for the presence of life, either.
But according to a pair of scientists (and now many media outlets as well), these geological features might only be explained by the presence of life.
Even within The Guardian's own article, we get a hint that the University of Buckingham's Chandra Wickramasinghe -- one of the two scientists pushing this claim -- might be what we'd call a fringe scientist:
Prof Wickramasinghe’s views are regarded as several steps outside the scientific mainstream. He has previously suggested that the SARS virus arrived to Earth from space and that airborne spores that caused rainfall in Kerala to turn a reddish hue had an extraterrestrial origin.
But here's the thing: Being a "maverick" scientist isn't really a good thing. Science is about consensus -- there's a lot of data to collect, a lot of interpretations to be made, and an awful lot of trial and error to discovering a new thing. If one or a handful of people believe something to be true, it might just be because they're ahead of their time -- but more often, it means they're interpreting the data differently from basically all other scientists, which usually means they're wrong.
In fact, renowned space blogger Phil Plait of Slate has debunked some of Wickramasinghe's "there might be life on --" claims before.
And according to The Telegraph, the Rosetta mission scientists are not about it:
However the scientists behind the mission said the comet was probably too inhospitable for life.“I think it is highly unlikely,” said Professor Monica Grady of the Open University who helped design the Ptolemy instrument carried by Philae.Rosetta project scientist Dr Matt Taylor also dismissed the claims.“It's pure speculation," he said: "I think it is unlikely."
The claims were ostensibly presented Monday at the National Astronomy Meeting in Wales, though at least one scientist present for the talk took to Twitter to point out that no real evidence was presented to support the idea.
Sarah M. Hörst, an assistant professor of Earth and Planetary Science at Johns Hopkins, didn't attend the meeting. But based on what she's read of Wickramasinghe's claims -- that the complex organic molecules and interesting activity on the comet are compelling signs of life -- she's comfortable debunking them as well.
"Complex organics are fairly easy to make if you have the building blocks (methane, formaldehyde, ammonia, carbon monoxide, carbon dioxide, water....) and an energy source (like photons from the Sun)," Hörst told The Post in an email. "The more complex (which in this context essentially means heavy) organics are, the higher their boiling point is (in general). We know complex organics are generated many places in the Solar System (Titan for example) through photochemistry and we know that type of organic material can be refractory (high boiling point) so I don't see any compelling evidence from the press release that there is evidence for anything other than abiotic chemistry."
In other words: Chemistry can get super complex without life being on the menu. In fact, Hörst said, she's working on making some complex organics in her lab right now.
The search for living microbes in hidden pockets of our solar system is really exciting. I, for one, think we'll probably find some -- and soon. But that doesn't mean a speculative shout of "there might be life here!" should be our default setting for space exploration.
In fact, what makes a comet with some of the features that might support life so interesting is that it probably doesn't. Scientists are figuring out what made Earth so special, and why so many of our neighbors got pieces of the same recipe but never cooked the microbial soufflé that lead to life as we know it.