First organic molecule found on extrasolar planet - March 19, 2008
Posted for Katharine Sanderson
Nature today carries an article about the detection of methane in the atmosphere of an extrasolar planet, HD 189733b, using the Hubble space telescope. This is nicely spun as “organic matter found on alien Earth” by ESA.
“This is a crucial stepping stone to eventually characterising prebiotic molecules on planets where life could exist”, said Mark Swain of NASA’s Jet Propulsion Laboratory, in Pasadena, USA, in the press release.
Hang on, let’s not get overexcited here: this is a great result, and hats off to the researchers for getting such a tricky measurement. Detecting anything so far away and so obscured by the brightness of its parent star, is a major achievement.
But I would urge caution, if not a few pinches of salt.
Swain is not saying he has found life. Sure, methane can be part of the prebiotic soup that life springs from, but it has also been detected in the atmosphere of many of the planets in our solar system, and as far as we know, those don’t harbour life.
HD 189733b is a gas giant, so far too hot for life as we know it anyway. Of course the researchers are quick to point this out: “The planet’s atmosphere is far too hot for even the hardiest life to survive — at least the kind of life we know from Earth,” says Giovanna Tinetti from the University College London and the European Space Agency.
Still, I bet any money that this story will be leapt upon as proof of little green men. Sigh.
What the work does show is that now astronomers have the tools to take accurate measurements and spectra of gases on far, far away planets, hugely increasing our understanding of what’s going on up there and allowing us to see for the first time what is happening in the atmosphere of these systems. And that is a very impressive achievement.
Who knows, perhaps one of these planets will be sufficiently Earth-like, and close enough to its star, and contain the right molecules, to harbour some sort of life. But a trace of methane and water can’t be taken as proof of that.
Previously on HD 189733b - Hazy red sunset on extrasolar planet.
Image: Artist's impression of HD 189733b / ESA, NASA and G. Tinetti (University College London, UK & ESA
UPDATE:
Coverage on this story was mixed. Some outfits did manage to stay calm and tell the story for what it was – a detection of a tiny molecule far, far away. But the majority predictably centred around life – and the discovery hailed as a breakthrough in the hunt for extraterrestrial life.
‘Methane gas raises hopes of life beyond Earth’, says the UK’s Independent. Steve Connor writes, incredibly optimistically, that the discovery “might soon lead to the discovery of extraterrestrial life.”
And the LA times also go down the little green man route with their “Hubble camera spots traces of life-forming gas”
Meanwhile the New York Times have the slightly more balanced ‘Stuff of life (but not life itself) is detected on a distant planet’. Sticking to the facts, they state: “Under the right conditions, water can combine with organic chemicals like methane to make amino acids, the building blocks of life as we know it.”
And the AP tells it like it is, with ‘Methane Detected on Distant Planet’.
Comments
There is more than adequate proof that "life" arises in the universe and no good reason to assume that it arises in isolation. So any confirmation that biomaterial is present elsewhere serves to strengthen the implication that this potential is universally present.
However, I would assume that methane in such quantity is the natural product of primitive atmospheric or volcanic processes and not evidence of a biological source.
Posted by: Steven Ericsson-Zenith | March 19, 2008 09:36 PM
In the wake of sf maestro Clarke's demise this news bears a special significance as Clarke was a firm believer of extraterrestrial life.
What a coincidence ...it is most befitting tribute to maestro.
Posted by: arvind mishra | March 20, 2008 01:39 PM