This week, two teams working independently announced the first unambiguous detection of light from planets orbiting other sun-like stars. The achievements, researchers say, help set humanity on the doorstep of a golden age in exploring solar systems beyond our own.
Until now astronomers have detected their quarry through fleeting shadows or the subtle quiver of underbrush. They've had to rely on the faint dimming of a star as a planet swings in front of it or, more often, tiny wobbles that planets impart to their parent stars as they orbit. Although the technique the two teams used also is indirect, it finally reveals infrared light coming directly from the planets.
That light carries a wealth of information about the molecular composition of the planets' atmospheres. Armed with that information, scientists will pierce a critical barrier to uncovering the range of planetary environments that solar systems in our galaxy have to offer. The ultimate hope: finding Earth-like planets whose atmospheres carry the chemical signatures of life.
"These results are historic," enthuses Geoffrey Marcy, an astronomer at the University of California at Berkeley who heads one of the world's most prolific planet-hunting teams.
Over the past decade, and especially within the past few years, astronomers have been uncovering extrasolar planets at a furious pace. Dr. Marcy estimates that solid detections of planets orbiting other stars now number about 150. "We've discovered nearly all of the Jupiters and Saturns that exist around stars out to about 100 light years from Earth," he says. Many of them are so-called hot Jupiters - huge gas-giants orbiting very close to their parent stars.
What we need is a 5-year space mission to seek out new life and new civilizations; to boldly go where....wait! Haven't I heard this before?....... Oh dear, another Star Trek reference! I'm getting geekier as I get older.