Astronomers seeing more planets than stars in galaxy

By Seth Borenstein

Associated Press

Published: Wednesday, Jan. 11 2012 10:11 p.m. MST

This 2011 handout photo provided by the European Southern Observatory, shows the Milky Way above the La Silla Observatory in Chile. The more distant telescope in the photo was used to survey planets in our galaxy using a time consuming technique. The results indicate that on average there are 1.6 larger planets per star in our solar system, but that?s mostly looking at planets that are far from their star. Other methods look more on close-in planets and putting those techniques together, astronomers think that means stars in the Milky Way probably average well over two planets. (AP Photo/Zdenek Bardon/ProjectSoft, European Souther Observatory)

Associated Press

WASHINGTON — The more astronomers look for other worlds, the more they find that it's a crowded and crazy cosmos. They think planets easily outnumber stars in our galaxy and they're even finding them in the strangest of places.

And they've only begun to count.

Three studies released Wednesday, in the journal Nature and at the American Astronomical Society's conference in Austin, Texas, demonstrate an extrasolar real estate boom. One study shows that in our Milky Way, most stars have planets. And since there are a lot of stars in our galaxy — about 100 billion — that means a lot of planets.

"We're finding an exciting potpourri of things we didn't even think could exist," said Harvard University astronomer Lisa Kaltenegger, including planets that mirror "Star Wars" Luke Skywalker's home planet with twin suns and a mini-star system with a dwarf sun and shrunken planets.

"We're awash in planets where 17 years ago we weren't even sure there were planets" outside our solar system, said Kaltenegger, who wasn't involved in the new research.

Astronomers are finding other worlds using three different techniques and peering through telescopes in space and on the ground.

Confirmed planets outside our solar system — called exoplanets — now number well over 700, still-to-be-confirmed ones are in the thousands.

NASA's new Kepler planet-hunting telescope in space is discovering exoplanets that are in a zone friendly to life and detecting planets as small as Earth or even tinier. That's moving the field of looking for some kind of life outside Earth from science fiction toward just plain science.

One study in Nature this week figures that the Milky Way averages at least 1.6 large planets per star. And that is likely a dramatic underestimate.

That study is based on only one intricate and time-consuming method of planet hunting that uses several South American, African and Australian telescopes. Astronomers look for increases in brightness of distant stars that indicate planets between Earth and that pulsating star. That technique usually finds only bigger planets and is good at finding those further away from their stars, sort of like our Saturn or Uranus.

Rover landing

LOS ANGELES — NASA's latest rover to Mars fired its thrusters Wednesday to adjust its course to the red planet for a landing in August.

Deep space antennas tracked the choreographed maneuver, which was expected to last three hours.

The firing of its eight thruster engines is the most important task Curiosity will perform during its 352-million-mile trip, but it's not unprecedented. Previous robotic explorers have had to adjust their paths several times en route to landing.

"Just because this is a well-traveled road to Mars given the number of trips we've made, I'm very careful to not let that experience cause us to be complacent," said Arthur Amador of the NASA Jet Propulsion Laboratory, which manages the $2.5 billion mission.

At the time of the course correction, Curiosity had racked up 80 million miles and was traveling at 10,200 mph relative to the Earth.

— Associated Press

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