The Search for an Earth-Like Planet

Ian Sample in the Guardian:

Astronomers may be on the brink of discovering a second Earth-like planet, a find that would add fresh impetus to the search for extraterrestrial life, according to a leading science journal.

Planet hunters have spotted more than 200 planets beyond our solar system, but the vast majority are hot, Jupiter-sized planets that would dwarf the Earth and are almost certainly lifeless.

Writing in the US journal Science, astronomers from six major centres, including Nasa, Harvard and the University of Colorado, outline how advances in technology suggest scientists are on the verge of being able to detect the presence of small, rocky planets, much like our own, around distant stars for the first time. The planets are considered the most likely havens for extraterrestrial life.

One technique relies on observing the shift in light coming from a star as a planet swings around it. Until recently, this "radial velocity" method has only been sensitive enough to pick up planets far more massive than Earth, but improvements now make the discovery of a second Earth highly likely, said Dave Latham, a co-author on the paper at the Harvard-Smithsonian Centre for Astrophysics.