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earth-like planet





yagnyavalkya
A ‘habitable’ earth-like planet, which is orbiting around a sun-like star 600 light years away, has been discovered in our galaxy for the first time, researchers say.
http://truthdive.com/2011/12/06/Habitable-Earth-like-planet-orbiting-Sun-like-star.html
The article is here
http://iopscience.iop.org/0004-637X/729/1/27
kelseymh
yagnyavalkya wrote:
A ‘habitable’ earth-like planet, which is orbiting around a sun-like star 600 light years away, has been discovered in our galaxy for the first time, researchers say.
http://truthdive.com/2011/12/06/Habitable-Earth-like-planet-orbiting-Sun-like-star.html
The article is here
http://iopscience.iop.org/0004-637X/729/1/27


I'm glad you put "habitable" in quotes, there Smile The radiation-equilibrium temperature for a rocky object in the orbit estimated for Kepler 22b (which you should have mentioned in your original post) is -11 C. You have to assume an atmosphere equivalent to Earth's in terms of greenhouse feedback in order to get a mean surface temperature of +22 C (72 F).

If you assume an atmosphere similar to Venus (which is obviously not unlikely, given that 50% of planets already known to be in the "habitable zone" have such an atmosphere), then you end up with a mean surface temperature of about 250 C.

There is negligible data (yet) on either the atmospheric composition or density of Kepler 22b. We don't even know (yet) what the planet's density, and hence surface gravity, is.
therimalaya
At least, we have some friends in this universe,... This is great news... But a lot of unknown doors of research is open now... When can we see and hear the news from that planet..?
Ankhanu
therimalaya wrote:
At least, we have some friends in this universe,... This is great news... But a lot of unknown doors of research is open now... When can we see and hear the news from that planet..?


You're making bold assumptions. That a planet exists in the "habitable zone" does not infer that it is, in fact, inhabited. There are still a lot of questions to be answered as to whether or not it actually can support (Earth-like, or any form of) life. Kelsey covered some of the questions in his post above.

Here's a piece by Philip Plait (Bad Astronomer) about it.

ocalhoun
Ankhanu wrote:
There are still a lot of questions to be answered as to whether or not it actually can support (Earth-like, or any form of) life.


And furthermore... even if it can support life... does it?
I wouldn't count on it as a sure thing that a livable planet would develop life forms... and even if that is a certainty... the timetable surely isn't... It might simply not have life yet... or life on that planet might have died out ages ago.
(And then, even if there is life, is that life advanced enough to possibly call 'friends'? I wouldn't say we have 'friends' out there in the universe if we discovered a planet inhabited only by alien bacteria...)
Ankhanu
Sorry, my intent was that that would be explicit, or at least implicit, in my post... guess I didn't succeed Wink
ocalhoun
*just noticed that the planets are to scale on that image*
Wow... 22b is big...
Are the inferring its weight from its size, or vice versa?
truespeed
Looking at that diagram it shows Mars as being in the habitable zone,and as far as we know that holds no life and maybe never has done,so habitable zone doesn't always = life.
kelseymh
ocalhoun wrote:
*just noticed that the planets are to scale on that image*
Wow... 22b is big...
Are the inferring its weight from its size, or vice versa?


They're inferring the mass from its diameter. Kepler uses the transit-occultation technique to find planets. The amount of dimming, along with the distortion of the light curve at the start and end of each transit, can be used to determine the diameter of the planet. The mass, and hence the surface gravity, depend on the average density of the planet, which is unknown.
brandon02852
Do we know what the surface is made of? If so, we could possibly determine if it does have elements for life and/or if it has ever been geologically active. What makes this planet earth-like anyway?
Ankhanu
brandon02852 wrote:
Do we know what the surface is made of? If so, we could possibly determine if it does have elements for life and/or if it has ever been geologically active. What makes this planet earth-like anyway?

No, we don't know.
There are multiple links in the thread explaining what we know of it, but what makes it "earth-like" is its orbit and the fact that it is solid rather than gaseous.
yagnyavalkya
Just to update here is a news item again http://www.telegraph.co.uk/science/space/8969451/Astronomers-find-earth-sized-planets-in-the-Goldilocks-zone.html
Which quotes the scientist Linda Elkins-Tanton as saying "If Kepler-20f was formed with water, which I think is likely, then it could have held on to its water for several billions of years ,"and that means that this planet could have been habitable in the past for a long period," she said. The system is located about 1,000 light-years away in the constellation Lyra". It is interesting
Ankhanu
Look at that, a news paper has the facts incorrect, at least with the headline Wink These planets are not in the "Goldilocks zone" at all, they're far too close to their star. The important thing here is that they were detected. Being similar in size, and even smaller than Earth makes them the smallest found planets so far, which is pretty exciting. The ability to detect them is what's so thrilling here.

Here's an article written by former NASA astronomer Philip Plait, rather than a journalist: http://blogs.discovermagazine.com/badastronomy/2011/12/20/another-kepler-milestone-astronomers-find-two-earth-sized-planets-orbiting-the-same-star/
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