At least one of 1,000 “planet candidates” discovered by NASA’s Kepler mission is a verified planet located in the habitable zone of its star, the mission’s scientists have confirmed.
“This is a major milestone on the road to finding Earth’s twin,” said Douglas Hudgins, a scientist with the Kepler program, in a statement Monday. The confirmation will be published in the Astrophysical Journal.
Kepler-22b, located about 200 light years away, has a radius 2.4 times bigger than the Earth, making it the smallest planet ever found in the middle of the habitable zone around a star – the area where liquid water, and therefore life as we know it, can theoretically exist. The planet orbits a star similar to our sun, but slightly smaller and cooler. It completes the orbit every 290 days. Scientists don’t yet know whether it is a rocky, gaseous or liquid-covered planet.
The Kepler space telescope, which orbits the sun between Earth and Mars, has been searching 156,000 stars in its field of view — about 1/400th of the sky — for signs of planets since September 2009.
In February, the mission announced it had found more than 1,000 possible new planet candidates, including 54 around the habitable zones of stars. Five were thought to be Earth-sized. However, scientists said at the time that more work was needed to confirm that the signals detected by Kepler were actual planets.
Kepler 22-b is the first of the 54 habitable-zone planet candidates to be confirmed.
Kepler searches for planets by measuring tiny decreases in the brightness of stars caused by planets crossing in front of them. A planet is considered “confirmed” after it has witnessed the same crossing or “transit” three times.
US Military Pays SETI to Check Kepler-22b for Aliens
The Search for Extra Terrestrial Intelligence (SETI) has announced that it is back in business checking out the new habitable exoplanets recently discovered by NASA’s Kepler space telescope to see if they might be home to alien civilisations. The cash needed to restart SETI’s efforts has come in part from the US Air Force Space Command, who are interested in using the organisation’s detection instruments for “space situational awareness”.
“This is a superb opportunity for SETI observations,” said Jill Tarter, the Director of the Center for SETI Research, in a statement issued yesterday. “For the first time, we can point our telescopes at stars, and know that those stars actually host planetary systems – including at least one that begins to approximate an Earth analog in the habitable zone around its host star. That’s the type of world that might be home to a civilization capable of building radio transmitters.”
NASA has just announced the discovery of many exoplanets orbiting other stars by its Kepler spacecraft, inclusing the world Kepler-22b – described as Earth’s “twin” by the space agency – which orbits a Sun-like G type star some 600 lightyears away at such a distance that it could well have liquid water on its surface and thus be home to life along Earthly lines.
Intriguingly, SETI notes that its resurgence and new mission of examining the Kepler-discovered planetary systems is partially funded by the US military:
The restart of SETI work at the ATA has been made possible thanks to the interest and generosity of the public who supported SETI research via the SETIStars.org website. Additional funds necessary for observatory re-activation and operations are being provided by the United States Air Force as part of a formal assessment of the instrument’s utility for Space Situational Awareness …
Could it be that the Pentagon are doing something useful for once and making sure that if there are any potentially hostile alien civilisations out there, they’ll find out early on?
Well no, sadly for those who like their aliens. In fact Space Command are much more concerned about tracking satellites in orbit around Earth, and consider that the innovative Allen Array could be handy in picking up transmissions from spacecraft so as to help the existing military Space Surveillance Network keep a handle on where they are.
Even so, should SETI detect signs of radio-using life at any of the newly pinpointed potentially habitable star systems, Space Command will probably be very glad they helped to fund the Institute’s restart.