Building block of life discovered on a distant planet

Washington, Mar 20 (UNI) Astronomers have detected an organic molecule, methane outside our solar system and have confirmed the presence of water there, raising the prospects of existence of life beyond this planet.

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.

''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, California, the lead author of the study.

Although methane has been detected on most of the planets in our Solar System, this is the first time any organic molecule has been detected on a world orbiting another star, he added.

The planet, HD 189733b, now known to have methane and water vapour is located 63 light-years away from earth in the constellation Vulpecula. HD 189733b, a ''hot Jupiter'' type planet, is so close to its parent star that it takes just over two days to complete an orbit.

''Hot Jupiters'' are the size of Jupiter but orbit closer to their stars than the tiny innermost planet Mercury in our Solar System. HD 189733b's atmosphere swelters at 900 degrees C, about the same temperature as the melting point of silver.

The observations were made by the Hubble Space telescope using spectroscopy, a technique which splits light into its components to reveal the ''fingerprints'' of various chemicals.

As the planet passed in front of its parent star in what astronomers call a transit, the gases in the atmosphere imprinted their unique signatures on the starlight from the HD 189733.

According to co-author Giovanna Tinetti from the University College London and the European Space Agency, ''Methane, composed of carbon and hydrogen, is one of the main components of natural gas, a petroleum product.'' ''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,'' Sciencedaily quoted him as saying.

''These measurements are an important step to our ultimate goal of determining the conditions, such as temperature, pressure, winds, clouds, etc and the chemistry on planets where life could exist,'' said Mr Swain.

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