NASA’s Kepler space telescope, which was named after 17th-century German astronomer Johannes Kepler, aims to discover Earth-like planets orbiting other stars. It launched March 7, 2009 and has a minimum expected mission lifetime of 3.5 years. So far, the Kepler space telescope has found 2,326 potential Earth-like planets.
Now, the telescope has made a new discovery that has NASA astronomers buzzing. The new planet is called Kepler-22b, and it is 600 light-years away from Earth. It was found in the middle of the habitable zone, which is the region around a star where temperatures are neither too hot nor too cold for liquid water to dwell.
Kepler-22b orbits a star very similar to the sun, except it’s a bit smaller and cooler. It orbits this star every 290 days.
The planet itself is 2.4 times the size of Earth, but that’s about all that is known about Kepler-22b. Its mass/composition is unclear at this point, meaning it could be a “global ocean” or entirely rocky.
“If this planet has a surface, it would have a very nice temperature of some 70 degrees Fahrenheit (21 degrees Celsius),” said William Borucki of NASA’s Ames Research Center. “It’s another milestone on the journey of discovering Earth’s twin.”
According to Borucki, the Kepler space telescope had to wait for Kepler-22b to pass three times before it could consider it a confirmed planet instead of just a candidate. The first passing was caught only three days after the Kepler space telescope was functional. Now, at the First Kepler Science Conference at NASA Ames, it was announced that the third passing occurred over the 2010 holiday season and Kepler-22b is officially an Earth-like planet -- and one of the closest to being Earth's twin to date, according to BBC News.
Kepler-22b differs from most habitable planets in that it orbits a star much like the sun rather than a red dwarf sun, which can be rather dim, and it is in the middle of the habitable zone rather than on the edge with harsher temperatures.
Since February 2011 alone, the Kepler space telescope has found 1,094 new planets, where 48 total have turned out to be genuine planets. The SETI Institute, which searches for extraterrestrial life in the universe via the Allen Telescope Array in California, says the Kepler space telescope’s findings, including Kepler-22b, are helpful in the effort to discover other life beyond Earth.
“We’re taking everything we can get from our Kepler colleagues to look for techno-signatures,” said Jill Tarter of the SETI Institute in Mountain View, California.
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