Hubble may have spotted 100 new planets
By ROBERT S. BOYD
Knight-Ridder Tribune News
WASHINGTON -- The Hubble Space Telescope may have discovered as many as 100 new planets orbiting stars in the Milky Way galaxy, astronomers say.
If confirmed, that would double the known population of alien planets since the first one was detected nine years ago, said Steven Beckwith, director of the Space Science Telescope Institute in Baltimore.
Astronomers are coming to believe that almost every sunlike star in the galaxy, and probably in the universe, is accompanied by one or more planets like our solar system, vastly increasing the chance that some form of extraterrestrial life could exist.
Hubble's expected harvest of previously unknown planets stems from a sweep of thousands of stars in the domelike bulge protruding above the flat disk of the Milky Way.
For seven straight days in late February, Kailash Sahu, an astronomer at the Baltimore institute, used the 14-year-old telescope to monitor the amount of light streaming from the brightest stars.
A tiny decrease -- less than a tenth of 1 percent -- in the light was a sign that something, perhaps a planet, was passing in front of the star. A similar phenomenon entranced millions of earthlings when Venus transited the sun June 8.
Sahu is now employing an older planetary-detection method to confirm that the transiting objects are really planets and not something else, such as dwarf stars or clouds of interstellar gas.
Using a large ground-based telescope in Chile, he's looking for small irregularities, or wobbles, in a star's motion that would prove that it's accompanied by one or more planets.
This is the method that's been used since 1995 to spot about 100 planets. Three more have been discovered by the new "transit" technique in the past year.
"If this is confirmed, in seven days we will have doubled the number of planets known in nine years," Beckwith told a committee of the National Academy of Sciences earlier this week.
The panel is exploring the future of the Hubble telescope.
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