A team of British and American astronomers have discovered, for the first time ever, a chemical that could spark life on a planet orbiting another star. They used the Hubble space telescope to spot the tell-tale signature of the molecule methane in the atmosphere of a giant gasball the size of Jupiter lying 63 light-years away.
Finding the gas – which is also produced by cows breaking wind on Earth – follows the discovery of water on the same planet last year.
The new find is a breakthrough because it proves that astronomers finally have the power to detect signs of life itself outside our own solar system.
Dr Giovanna Tinetti, of University College London, was part of the team that made this first-ever discovery of an organic molecule on another world. The planet, labelled simply HD 189733b, lies in the constellation of Vulpecula, the Fox.
Her observations, made with colleagues from Nasa’s Jet Propulsion Laboratory in California, also confirmed the existence of water molecules that was made last year using another space telescope called Spitzer.
Dr Tinetti said yesterday: “We haven’t found life on another planet yet, but this in an exciting step towards showing that we can detect these signature molecules where they are present in the Universe.”
Methane is a natural gas produced on Earth from sources including oceans, wetlands, rubbish tips and cows breaking wind – it is estimated that all the cattle in the world produce 100 million tonnes a year.
But scientists are ruling out windy aliens as the cause of the methane they have detected. Dr Tinbetti said: “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. It’s highly unlikely that cows could survive here!”
Only last week, we reported how clouds of water had been detected in the dust and gas orbiting a young star. That followed the discovery of organic molecules in another newly forming solar system.
The flood of new findings confirm the view expressed by Nasa last year that telescopes are now collecting enough information from the atmospheres of exoplanets to identify ET’s fingerprints.
In the latest find, the methane – made up from carbon and hydrogen – was detected as the planet passed in front of its star, allowing light travelling through the atmosphere to be analysed.
Under the right circumstances methane can play a key role in the chemical reactions considered necessary to form life as we know it – a process called prebiotic chemistry.
Team leader Mark Swain said: “This is a crucial stepping stone to eventually characterising prebiotic molecules on planets where life could exist.” He added: “With this observation there is no question whether there is water or not – water is present.”
The planet is nothing like the Earth. It is of a type called a “hot Jupiter” and zips round its parent star so quickly that its year is just two Earth-days long.
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