First new solar system discovered

April 16, 1999
by Paul Hoversten

Astronomers said Thursday that they had found the first multiplanet solar system outside our own, a discovery that could boost the search for life in the universe.

The discovery, the researchers said, suggests that our Milky Way galaxy, which contains 200 billion stars, could be teeming with solar systems and that some of them might have Earth-like planets or moons that can support life.

"We are witnessing the emergence of a new era in human exploration," said Geoffrey Marcy, co-leader of one of the teams that found the system.

The three planets are Jupiter-size and orbit the star Upsilon Andromedae, 44 light-years from Earth. A light-year is about 6 trillion miles.

The planets are gas giants and probably unsuitable for life. But they could have moons where water might exist, much as Jupiter's moon Europa is believed to have an ocean beneath an icy crust.

"There's no reason to rule out the existence of warm, habitable rocky planets or satellites in this particular system," said astronomer Robert Noyes of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.

	?Are there any similarities between the solar system of Upsilon Andromedae and our own solar system? ?How would the notion of time chnage for humans if they were able to inhabit the planets that orbit Upsilon Andromedae? What would an average "day" be like? How do you think the "seasons" would vary? ? Use the information in the article to define a new life-form that could survive in the current environment of any one of Upsilon Andromedae's three known planets. Describe how this life-form appears and how it gets nourishment, grows, reproduces, dies, etc.

Noyes and teams from San Francisco State University and the High Altitude Observatory in Boulder, Colo., found the system using telescopes in California and Arizona. They detected the planets by monitoring the host star's wobble, which is caused by the gravitational tugs of the planets.

Upsilon Andromedae, a bright star in the constellation Andromeda, is visible to the naked eye. It is about 1.2 times the size of our sun and roughly two-thirds its age at 3 billion years.

Since 1995, astronomers have found 20 individual planets beyond our solar system. But this is the first time a solar system with multiple planets has been found.

Marcy and colleague Paul Butler, who are credited with finding 14 of those 20 planets, found the innermost of Upsilon Andromedae's three planets in 1996. The other two were found in early March after 11 years of observations.