Planet spotting

The leading method of finding planets orbiting distant stars spots mostly Jupiter-sized worlds but technology limitations make it difficult to detect smaller planets.

A new technology being developed by scientists and engineers at the Harvard-Smithsonian Center for Astrophysics (CfA), with colleagues at MIT, will enable scientists to spot Earth-sized worlds in Earth-like orbits.

'With this technology we are developing, astronomers will finally be able to find the first truly Earth-like worlds in terms of size and orbit,' said CfA astrophysicist Chih-Hao Li.

Planets orbiting other stars are much too faint and far away to be seen directly and photographed. Instead, astronomers must look for the planet's effect on its star.

While the gravity of a star tugs on a planet and holds the planet in orbit, the planet's gravity also tugs on the star. That tug makes the star wobble slightly back and forth. If the wobble is along our line of sight, then sensitive instruments called spectrographs may be able to detect it.