Researchers have found a system of planets that is much like our own solar system RELATED VIDEO CNN's Greg Lefevre reports on the discovery of a solar system similar to ours Real 28K 80K Windows Media 28K 80K QUICKTIME Animation of Upsilon Andromedae 719 K / 240x180 QuickTime movie Please enable Javascript

April 15, 1999
Web posted at: 1:45 p.m. EDT (1745 GMT)

WASHINGTON (CNN) -- Astronomers said Thursday they had discovered the first solar system with multiple planets outside our own, with three massive planets orbiting a sun-like star.

All three planets circling the star Upsilon Andromedae are gas giants like Earth's big neighbor Jupiter. However, an Earth-type planet might also be a part of this system, one researcher said.

"Our observations can't rule out Earth-sized planets as well in this planetary system, because their gravity would be too weak for them to be detectable with present instruments," Peter Nisenson of the Harvard-Smithsonian Center for Astrophysics said in a statement.

Astronomically, the system is not far away: 44 light years. Its sun is so near and bright, it can be seen by the naked eye during summer and fall.

Scientists have previously identified at least 18 extrasolar planets, but this was the first time they detected a system comparable to the nine-planet grouping that includes Earth.

"What we have found now, for the first time ever, is indeed a full fledged system of planets around the star Upsilon Andromedae," said Geoffrey Marcy, professor of astronomy and physics San Francisco State University.

Animation showing the inner planet that revolves around Upsilon Andromedae every 4.6 days

The finding suggests that there may be far more planets in our galaxy than previously thought, the researchers said.

"When I look up at the stars now at night I can imagine easily that every one of them has planet around them," says Debra Fischer, a professor of physics and astronomy at San Francisco State University.

Astronomers have searched for planets outside our solar system by focusing on the behavior of certain sun-like stars, such as Upsilon Andromedae.

Stars with a characteristic wobble are believed to have a large planet orbiting around them, with enough gravity to tug on the star.

Astronomers had earlier identified one of the three planets -- the closest one to this star -- but only recently determined that there were two others from their gravitational affect on Upsilon Andromedae.

Can they support life? Scientists don't know, because present technology is not advanced enough to determine what the planets are made of. That, Marcy says, is astronomy's next challenge.

San Francisco Bureau Chief Greg Lefevre and Reuters contributed to this report.

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