Life in space?
October 20, 2009
Some of the 32 newly discovered planets are just a few times larger than Earth. The astronomers said this increases the possibility that conditions on them could give rise to life.
Researchers announced their findings on Monday, October 19, at a conference in Porto, Portugal. They said the discovery could mean that 40 percent or more of Sun-like stars have such planets - so-called exoplanets - in orbit around them.
Stephane Udry of the Geneva Observatory in Switzerland said the recent discovery brings the total number of known exoplanets up to 400.
Most of these are giant balls of toxic gas, which are unsuitable for life as we know it. However, 28 are so-called "super-Earths," with masses 20 times the size of Earth or less, which means they could be rocky instead of gaseous, the European Southern Observatory (ESO) said in a statement.
"Nature doesn't like a vacuum, so if there is space to put a planet it will put a planet there," Udry told reporters in Porto.
None of the newly found exoplanets are Earth-like, said the researchers. However, whether any of them could be home to carbon-based life forms would depend on where they orbit in relation to their stars.
Earth itself is located in a zone where the temperature is "just right" - neither too hot for our atmosphere to be stripped away, nor too cold for seas to freeze. It can therefore contain liquid water - the stuff of life.
High-powered telescope
The discovery of the 32 planets was made using HARPS - the High Accuracy Radial Velocity Planet Searcher - which is a spectograph attached to ESO's 3.6-meter (11.8-foot) telescope located in La Silla, Chile. The planets are too small to be seen directly, but scientists are able to calculate their size and mass by measuring the gravitational impact they have on the stars they orbit.
HARPS was developed by experts from the Geneva Conversatory and is the most successful planet spotter, having detected 75 of the 400 known exoplanets.
kjb/AFP/Reuters
Editor: Louisa Schaefer