Earth-Like Planets Feature in New Survey

Tired of life on Earth? There may be other options, according to a catalog released on Monday of planets and moons that could have the right conditions to support life, planetary scientists said.

A total of 47 exoplanets and exomoons are potential habitable candidates, according to the online ranking of bodies outside our solar system by the Planetary Habitability Laboratory (PHL) of the University of Puerto Rico at Arecibo.

Two of the exoplanets are confirmed to have the right distance from their star to support water, plus a suitable temperature and atmosphere to support life.

But be warned, it would take Earthlings quite a long trip to get there.

One of the "marginally Earth-like" planets, Gliese 581d, is 20 light years from Earth, and the other, HD 85512b, is 36 light years away.

They are among the 700 exoplanets that have been detected and confirmed by missions such as NASA Kepler space telescope.

The Habitable Exoplanets Catalog (HEC), available online at http://phl.upr.edu, is the first to classify exoplanets and exomoons them according to their habitability in a somewhat user-friendly format.

The rankings give scientists "the ability to compare exoplanets from best to worst candidates for life," said says Abel Mendez, director of the PHL and principal investigator of the project.

Proposed future missions, such as the NASA Terrestrial Planet Finder (TPF), would be needed to confirm the suitability for life of the other 45 candidates identified in the catalog.

"I hope this database will help increase interest in building a big space-based telescope to observe exoplanets directly and look for possible signatures of life," said Jim Kasting, an expert on planetary habitability science from Penn State.

Kepler is NASA's first mission in search of Earth-like planets orbiting suns similar to ours.

It launched in 2009, equipped with the largest camera ever sent into space -- a 95-megapixel array of charge-coupled devices -- and is expected to continue sending information back to Earth until at least November 2012.

The space telescope is searching for planets as small as Earth, including those orbiting stars in a warm, habitable zone where liquid water could exist on the surface of the planet.