Search for Alien Life gets a boost

Pictured released on December 09, 2008 and taken by the NASA/ESA Hubble Space Telescope which has discovered carbon dioxide in the atmosphere of a planet orbiting another star. This is an important step along the trail of finding the chemical biotracers Photo: Nasa

The Hubble space telescope has uncovered a distant planet with carbon dioxide in its atmosphere – an important step forward in the search for extraterrestrial life.

Water vapour and methane have also been detected on HD 189733b, which is 63 light-years away and about the size of Jupiter.

Although the planet is far too hot to sustain life, astronomers hope the techniques that allowed them to detect these compounds – which can be evidence of life – will lead to a breakthrough in the hunt for distant Earth-like planets.

"The carbon dioxide is kind of the main focus of the excitement, because that is a molecule that under the right circumstances could have a connection to biological activity as it does on Earth," said Mark Swain of NASA's Jet Propulsion Laboratory in Pasadena, California.

"The very fact that we're able to detect it, and estimate its abundance, is significant for the long-term effort of characterising planets both to find out what they're made of and to find out if they could be a possible host for life."

Astronomers used Hubble's Near Infrared Camera and Multi-Object Spectrometer (NICMOS) to detect the chemicals, by analysing infrared light emitted from the planet. Different gases in the atmosphere absorb different wavelengths of the 1,800 F (1,000C) planet's light, allowing scientists to identify which chemicals are present.

The Hubble space telescope was launched in 1990 to take clear images of space from outside the Earth's atmosphere and is run as a joint project by NASA and the European Space Agency (ESA)
Giovanna Tinetti from University College London, who is part of the team studying HD 189733b, said that the discovery of CO2 opened new doors in planetary research.

"In the terrestrial planets of our solar system, carbon dioxide plays a crucial role for the stability of climate. On Earth, carbon dioxide is one of the ingredients of the photosynthesis and a key element for the carbon cycle.

"Our observations represent a great opportunity to understand the role of carbon dioxide in the atmospheres of hot Jupiter type planets".