Scientists are on the verge of discovering ET’s fingerprints thanks to a breakthrough in space. An orbiting telescope has collected enough light from alien worlds to identify individual ingredients that make up their atmospheres.
No one is more surprised than the astronomers themselves that they can identify particular molecules in the air of planets around other stars.
The data was collected by the agency’s Spitzer space telescope when it looked at the rainbow of light from two giant gaseous bodies like Jupiter.
Called exoplanets, one is labelled HD 189733b and lies 370 trillion miles away in the constellation Vulpecula. The other, HD 209458b, is 904 trillion miles away in the constellation Pegasus. The atmospheres were analysed by observing changes in the spectrum of light as the planets passed in front of and disappeared behind their stars.
Earlier this month, we revealed that the Hubble space telescope had detected the atmosphere of HD 209458b which has been unofficially named Osiris. And last year, we told how Spitzer observations had allowed scientists to check out the weather in other solar systems.
Astronomers are now searching for smaller planets like Earth using probes such as Europe’s £50million Corot probe which blasted off in December. Nasa believe that if Spitzer applies the same techniques on Earth-like worlds, we could see our first signs of ET.
Spitzer’s result has come years before astronomers had expected to probe alien atmospheres in such detail. “This is an amazing surprise,” said Spitzer project scientist Dr Michael Werner of Nasa’s Jet Propulsion Laboratory, in California. “We had no idea when we designed Spitzer that it would make such a dramatic step in characterising exoplanets.”
Spitzer’s observations gave scientists another surprise. They showed that the two exoplanets – dubbed hot Jupiters because they lie close to their parent suns – are drier and cloudier than predicted. Experts say the reason could be that high clouds of dust are hiding the water from the space telescope’s view.
Nasa’s Dr Jeremy Richardson said of the results, published in Nature: “The theorists’ heads were spinning when they saw the data. It is virtually impossible for water, in the form of vapour, to be absent from the planet, so it must be hidden, probably by the dusty cloud layer.” Picture: An artist’s impression of a hot Jupiter. Nasa/JPL-Caltech.
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