An artist's conception of the 6-planet system of Kepler 11
This is absolutely stunning! Kepler mission has so far detected 1235 candidate planets (see here for details on how Kepler detects planets). Out of these, 68 are the size of the Earth! Wait. This is not all. Astronomers usually get more excited to find planets orbiting in the habitable zone of the star. This is the distance at which water can stay in liquid form. For our Solar system, Earth and Mars are in the habitable zone (though Mars is right at the edge). We think if there is liquid water, then there is a good chance there is life there as well.
Well, Kepler has found 54 candidates in the habitable zone - and 5 of these are close to the size of the Earth. Wow!
Oh wait. And Kepler also has a confirmed detection of a planetary system, Kepler 11, with at least 6 planets orbiting the parent star. This is located about 2000 light years away and is a weird system (at least weird for us - and we are weird for the aliens living on these planets) as all six planets have orbits smaller than Venus, with five orbiting even closer than our Mercury. Very cool!
If you are a betting person, I would advise against betting your house against astronomers finding signatures of life within the next 10-15 years. Most likely, it is going to be through spectroscopy of the atmospheres of one of the small earth-sized planets located in one of the habitable zones. Then the discussion will quickly shift to: Oh there is no way there can be complex life forms out there. Hmm...well just a wait a bit more.
Read the Kepler press release here.
WOW. Thats thrilling :)
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ReplyDelete@Sean
ReplyDeleteThe Navis ride six legged horses that feed on flower nectar. They wouldn't need the runway...:-D
Hi Salman,
ReplyDeleteI just checked this link for the number of known planets.
http://planetquest.jpl.nasa.gov/
Despite Kepler's discovery, the planet count is given as 515.
Why?
"Despite Kepler's discovery, the planet count is given as 515.
ReplyDeleteWhy?"
Ali,
Good point. This is because most of Kepler's planets so far are candidates. It uses eclipses to detect planets. But, in order to be 100% sure, one has to confirm a second pass in front of the star. As you can imagine, some a star with the orbit of the Earth would pass again a year later - and those that farther away from the parent star, will do so even later. Therefore, most of these detections will be confirmed in the next couple of years. Though Kepler-11 - the 6 planet system - is confirmed (5 of these have orbits smaller that Mercury).
Can Kepler be completely wrong? Probably not. It now has some confirmed detections already - and astronomers can judge from that the likelihood that a candidate will be confirmed or not.
Back to the numbers. The JPL site only lists those planets that have been fully confirmed.
Thanks, Salman.
ReplyDeleteThat was helpful.