NASA scientists have found the basic ingredients for life in a second giant planet outside our own solar system. The alien world is a so-called “hot Jupiter” made mainly of gas and so could not harbour life as we know it.

But the discovery of the right chemistry boosts chances that life will exist on smaller rocky worlds around the stars.

The planet, orbiting a star called HD 209458 in the constellation of Pegasus, is only the second where the right set of ingredients for life has been detected.

The news comes just a day after European astronomers revealed they have spotted another 32 planets, bringing the total known to over 400.

Researcher Mark Swain of NASA’s Jet Propulsion Laboratory in California, said: “It’s the second planet outside our solar system in which water, methane and carbon dioxide have been found, which are potentially important for biological processes in habitable planets.

“Detecting organic compounds in two exoplanets now raises the possibility that it will become commonplace to find planets with molecules that may be tied to life.” He added: “This demonstrates that we can detect the molecules that matter for life processes.”

Swain and his team mde observations with two space telescopes, Hubble and Spitzer, to study HD 209458b, a hot, gaseous giant planet bigger than Jupiter that orbits a sun-like star about 150 light years away.

The new finding follows their breakthrough discovery in December 2008 of carbon dioxide around another hot, Jupiter-size planet, HD 189733b. Earlier Hubble and Spitzer observations of that planet had also revealed water vapour and methane.

The detections were made through spectroscopy, which splits light into its components to reveal the distinctive spectral signatures of different chemicals.

Picture: An artist imagines how the giant planet HD 209458b would look. (Credit:  JPL/NASA).

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