Discovery of coolest earth-like planet.

• Position: Astronomy - Brief article

A new planet five times the size of Earth has been discovered by an international team of astrophysicists. To date, it is the smallest ever found outside of our solar system. Using a network of telescopes scattered across the globe, the group says the extrasolar planet is more Earth-like than any ever sighted. It circles its parent star every 10 years. The discovery opens a new chapter in the search for planets that support life.

"That fact that we stumbled on one means there are thousands of them out there," asserts Ken Cook, an astronomer at the Lawrence Livermore (Calif.) National Laboratory, who also is a member of PLANET (Probing Lensing Anomalies NETwork), a part of the group that made the discovery. "Its mass is low enough that it couldn't hold itself together if it were just gas."

The planet and its red dwarf parent star lie in the constellation Sagittarius, not far from the central bulge of our...