7 Earth-sized exoplanets spotted

For the first time, seven Earth-sized exoplanets that may be able to sustain life have been discovered orbiting a star 39 light years away, astronomers said today.

“They could have some liquid water and maybe life,” researcher Michael Gillon, with the University of Liege in Belgium, was quoted as saying by journal Nature.

Astronomers have found other seven-planet systems before, but this is the first time to have so many Earth-sized worlds. All of them orbit at the right distance to possibly have liquid water somewhere on their surfaces.

Only marginally larger than Jupiter, the star shines with a feeble light about 2,000 times fainter than Earth’s sun, the journal said.

The researchers have caught only two glimpses of one of those planets, so they followed up on the faint signals with other telescopes. That process included 20 consecutive days when NASA’s Spitzer Space Telescope stared at the star. The resulting data showed what the scientists thought was a single planet was actually four that orbit their star every 4, 6, 9 and 12 days.  Those four joined the two innermost planets, which whirl around the star once every 1.5 days and 2.4 days. They also caught a hint of a seventh, more distant planet.