Three of the smallest planets to be detected beyond the sun, all orbiting a single red dwarf star, have been found by the Kepler spacecraft, and scientists say there may be similar planets all over the galaxy.
Using data from the Kepler mission, scientists found planets about 0.78, 0.73 and 0.57 times the radius of the earth, the National Aeronautics and Space Administration said in a report today. The smallest of the planets is the size of Mars, the agency said.
The three planets, all rocky like the Earth, are probably too close to their star to have liquid water, the report said. A red dwarf star, is the most common type in the Milky Way. This particular one is a sixth the size of the sun, or almost twice the size of Jupiter, according to NASA. The finding suggests that there could be similar rocky planets all over the galaxy, scientists said in the statement.
“Astronomers are just beginning to confirm thousands of planet candidates uncovered by Kepler so far,” said Doug Hudgins, who is a Kepler program scientist at NASA’s headquarters in Washington, in the statement. “Finding one as small as Mars is amazing, and hints that there may be a bounty of rocky planets all around us.”
The Kepler spacecraft, launched in 2009 to find habitable celestial bodies, has identified 2,326 planet candidates, of which 35 are confirmed planets. Of 1,235 planet candidates NASA announced last February, about 68 are Earth-sized and about 54 are in the habitable zone, which isn’t too hot or cold for life. Five planets are both Earth-sized and in the habitable zone.
Far-Off Probe
While the Kepler craft is finding planets that move close to their stars, astronomers are using a different method to probe for planets that are further away.
According to a study published today in Nature, astronomers using a technique called microlensing determined that planets that are distant from their stars are “at least as numerous as the stars in the Milky Way.”
The study estimates that the every star in the Milky Way galaxy has 1.6 planets.
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