Search for alien life about to step up a gear

It remains in the realm of science fiction for now but the discovery of a new planet just four light years away will reignite a race to find a twin of planet Earth that may host extraterrestrial life.

The step change comes as the most powerful telescopes ever built are about to enter into service and as ideas about where life could exist are being turned on their head. At the same time, scientific discussion about the possible existence of alien life is becoming more mainstream.

"I think scientists are very happy having a rational conversation about the likelihood of life out there," said Bob Nichol, an astronomer at Portsmouth University in Britain.

Nichol said this was partly driven by the discovery of new planets such as one identified this week in the Alpha Centauri star system, the closest yet outside our solar system.

Over 800 of these so-called exoplanets have been discovered since the early 1990s.

"An explosion in the number of planets makes it so much more likely," said Nichol, adding that the many formats in which life appears on Earth is indirect evidence, though not proof, that life is out there.
Researchers from the Geneva Observatory said the newest planet to be found was too close to its own sun to support life. But previous studies have suggested that when one planet is discovered orbiting a sun there are usually others in the same system.

Rival astronomers are now likely to start scouring Alpha Centauri for more planets, possibly in the habitable zone around its stars.