The Kepler Space Telescope, a designated planet-hunting satellite, has found its first five planets, among them an odd, massive world only as dense as Styrofoam.
The number of planets now known outside the solar system has risen to more than 400, but none is yet Earth-like enough to harbor life. Right now, Kepler can only detect large planets orbiting close to their stars, which means that these first planets are too hot to hold liquid water, a requirement for life as we know it.
But over the next year, the mission's scientists will be homing in on ever more life-friendly places.
"We expected Jupiter-size planets in short orbits to be the first planets Kepler could detect," said Jon Morse, director of the Astrophysics Division at NASA in a release. "It's only a matter of time before more Kepler observations lead to smaller planets with longer period orbits, coming closer and closer to the discovery of the first Earth analog."
Kepler is pointed at a single field of stars in the constellation Cygnus. By watching the same stars over time, the mission can detect the periodic dimming of those stars, a possible indication that a planet has passed in front of the star. Finding an Earth-like planet will probably take quite awhile, though, because if it has an Earth-like orbit, it will take around a year to cross in front of its star just one time.
The current set of Kepler planets are not much like ours at all. The smallest is 0.4 times the size of Jupiter, while the largest is 1.5 times the largest planet in our solar system. They are all very hot, too, running between 2,200 and 2,900 degrees Fahrenheit. They have been given the catchy names Kepler 4b, Kepler 5b, Kepler 6b, and Kepler 7b. (Kepler 1b-3b were assigned to previously known exoplanets in the telescope's field of view.)
Still, the planet detections show that Kepler is in great working order as it monitors its sample of the sky. The precision of the instrument has astounded scientists since its first light.
“This exquisite data is just the tip of the iceberg,” MIT astronomer Sara Seager said back then. “We’re going to see a new world of exoplanet exploration where discoveries will come much more rapidly than they’ve come in the last 10 years.”
The mission, championed for more than a decade by Bill Borucki, a NASA extrasolar planet specialist, looks like it will be capable of completing all of its scientific goals. That means it's just a matter of time before we find an Earth twin or two out there in the light-years beyond.
Image: NASA exoplanet rendering.
See Also:
- Most Earth-Like Extrasolar Planet Found Right Next Door
- Kepler Shows Exoplanet Is Unlike Anything in Our Solar System
- Extreme Exoplanet's Wild Ride
- Smallest Exoplanet Is Most Earth-like Yet
- Astronomers Find Hidden Exoplanet in Hubble's Dustbin
- Stellar Lithium Points Way for Exoplanet Hunters
- Aack, No Brakes! Giant New Exoplanet Goes the Wrong Way
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