Last Updated: Mon Nov 01, 2010 19:44 pm (KSA) 16:44 pm (GMT)

Astronomers find solar system with five planets

55 Cancri is a sun-like star with five planets circling it
55 Cancri is a sun-like star with five planets circling it

NASA scientists announced Tuesday, the discovery of a fifth planet orbiting a sun-like star outside our own solar system, raising further hopes that life may one day be found elsewhere in the universe.

The newfound planet is much bigger than Earth and is part of a group of four planets circling a star known as 55 Cancri, which is 41 light-years away in the constellation Cancer.

Geoff Marcy, an astronomer at the University of California, Berkeley, said the discovery showed that other solar systems similar to the one in which Earth is located might be discovered in other reaches of outer space.

"This discovery of the first ever quintuple planetary system has me jumping out of my socks," Marcy told a teleconference call.

"The significance is marvelous. We now know that our sun and its family of planets is not unusual," he said.

"It shows that our Milky Way contains billions of planetary systems ... we strongly suspect that many of these planetary systems harbor Earth-like planets," he said.

The newly discovered planet is about 45 times the mass of Earth and is believed to be similar to Saturn in its composition and appearance, the astronomers said.

The planet was discovered through observation using the Shane telescope at the Lick Observatory in San Jose, California and the W.M. Keck Observatory in Hawaii.

Harboring life?

The planet is ranked fourth from 55 Cancri and completes one orbit every 260 days. Its location puts the planet in the "habitable zone," a band around the star where temperatures would allow water to form in pools on solid surfaces.

"It would be a little bit warmer than the Earth but not very much," said Jonathan Lunine, a planetary scientist at the University of Arizona.

"If there were a moon around this new planet ... it would have a rocky surface, so water on it in principle could puddle into lakes and oceans," said Marcy.

Life could conceivably live on the surface of such a moon, but it would be far too small to detect using current methods, the astronomers said

Marcy and other astronomers strongly believe that many stars are hosts to solar systems similar to our own. But small objects such as planets are very hard to detect.

Technology that would allow scientists to detect planets as small as Earth is decades away, the scientists agreed.

The inner four planets of 55 Cancri are all closer to the star than Earth is to the sun and were discovered between 1996 and 2004.

"When you look up into the night sky and see the twinkling lights of stars, you can imagine with certainty that they have their own complement of planets," Marcy said.

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