Scientists Have Not Discovered Life on Comet 67P

Speculation Runs Rampant in the Face of Facts

I know it’s very tantalizing to fantasize about life on other worlds, or think about comets and asteroids strewing life-seeds around the planets as they go around the Sun. It’s fuel for hours of fun discussion at cocktail parties, and there’s some serious science going on investigating these possibilities.

But, come on, these stories in the mainstream media, fed by a press release that should have never have escaped from the Royal Astronomical Society reporting on what astrobiologists Max Wallis and Chandra Wickramasinghe speculated about Comet 67P are just plain wrong.

Let me put it plainly. There has been NO life found on Comet 67P/Churyumov-Gerasimenko. None.  Scientists have found all kinds of very cool and amazing surface features, and have been witnessing jets carving up the surface. But, they haven’t found life there, no matter how much a pair of eminent scientists want to speculate differently.

What Does the Team Say?

If the Rosetta team mission scientists had found life — and none of their instruments are built to detect the kind of life being suggested exists there — they’d be talking it up big time right now. But the team can’t and in fact, has come out saying that finding any life on the comet as “highly unlikely.” And that’s as it should be. Extraordinary claims require extraordinary proof, which doesn’t exist. And, these stories are just not doing justice to the actual real science of astrobiology, which also requires the same rigorous proof as other disciplines.

The articles I’ve seen are reporting on the commentary of two scientists who not on the Rosetta mission. These are two people who have been long active in the search for life elsewhere. They made some suggestions that the presence of organics on the comet are evidence of some kind of action by micro-organisms. They have nothing to prove their suggestions, but that hasn’t stopped the press, led by the Guardian, to run wild with a “LIFE FOUND!!!” story. (To be fair, the Guardian has now published a more sensible article.)

Despite what the actual Rosetta mission scientists have said — and you’d think they’d be the most qualified to speak about the comet they’re actually studying, right? — some journalists have just taken the press conference as dictation and published stories conflating”carbon-rich compound” and “organic molecules” with “life”.  Not quite, folks. They’re precursors, but they aren’t life. Something which escaped the notice of the writers of the clickbait stories I’ve seen floating around.

Finding Life Tantalizes Us

Now, since all life is chemical, finding organic compounds (also made up of chemicals) necessary to create life is important. And, there ARE organics on the comet. In fact, they’re all over the solar system, including comets. That makes them quite common. But, carbon-rich organic compounds aren’t living beings, any more than a mixture of water and clay is a living being.

Finding them on Comet 67P is NOT the same as finding life there. It’s like saying, “There’s water on that planet, so there must be life.” Water doesn’t equal life any more than carbon-based dust does. It’s part of the environment that might be hospitable for life, but it’s not life.

What the Comet Actually Shows Us

There are some pretty interesting features on the surface of 67P, but most of them are explained by dust jets, dust deposition, sublimation of ices off the surface, and so on. To claim, without evidence — that microbial life, which hasn’t been found anywhere but Earth (so far) — has anything to do with mini pits, surface etchings, and  boulders on the surface of the planet. Since we know the chemical composition of the comet’s surface, it’s best to go with the explanations that work for that complex mix of gases, ices, and dust.

To be honest, the best possible explanations for the surface features on the comet come from studying the processes at work on the materials already there. Those are processes such as sublimation and solar heating, which leads to jets cutting through the mix of ices and dust that make up the comet. Those processes that act on ices and dust in a vacuum can easily explain what we’re seeing. No need to invoke life, which requires another magnitude of complexity and a lot of other chemistry that hasn’t been detected there.

I really do get tired of these stories from the “mainstream media” that pick up little interview bits with scientists but don’t bother to check the facts or ask the tough questions. The writers who posted the original story (based on a press release) just accepted everything at face value and ran with a wildly screaming “LIFE on a COMET!!!” story.  It sells papers and views on web sites, but it’s click bait journalism and does no one any favors. (Well, it sells ads, but that’s not why we do science, folks.)

The story of Rosetta at Comet 67P is cool already, we don’t need jazzed up headlines falsely implying life on the comet to sell clicks to interest the public.