a planet that is outside our solar system.


     In a long-awaited announcement, scientists operating NASA's Kepler planet-hunting satellite reported on Wednesday that they had identified 1,235 possible planets orbiting other stars, potentially tripling the number of known planets.


Of the new candidates, 68 are one and a quarter times the size of the Earth or smaller — smaller, that is, than any previously discovered planets outside the solar system, which are known as exoplanets. Fifty-four of the possible exoplanets are in the so-called habitable zones of stars dimmer and cooler than the Sun, where temperatures should be moderate enough for liquid water.


See article at: WSJ 03Feb11 – Kepler Planet Hunter Finds 1,200 Possibilities


In a down payment on riches to come, scientists from NASA's Kepler satellite announced Monday that they had discovered the smallest planet yet found outside our solar system and the first that was unquestionably rocky, like the Earth.

The planet, known as Kepler 10b, is only 40 percent larger than the Earth and about 4.6 times as massive, making it about as dense as Mercury.  It is lethally hot, orbiting its star in 20 hours at a distance only one-twentieth of that of Mercury from the Sun.  . . .

More than 700 exoplanets, as planets around other stars are called, have been detected over the last 15 years. A vast majority of them are Jupiter-size giants, but as techniques have improved, astronomers have been able to detect smaller and smaller planets."

See article at: NYT 11Jan11: "Kepler Finds an Exoplanet, Rocky, Small and Very Hot"