INTENSITY²
Start here => What's your crime? Basic Discussion => Topic started by: skyblue1 on December 05, 2011, 05:48:09 PM
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Kepler 22-b,Earth-like planet confirmed
Astronomers have confirmed the existence of an Earth-like planet in the "habitable zone" around a star not unlike our own.
The planet, Kepler 22-b, lies about 600 light-years away and is about 2.4 times the size of Earth, and has a temperature of about 22C.
It is the closest confirmed planet yet to one like ours - an "Earth 2.0".
However, the team does not yet know if Kepler 22-b is made mostly of rock, gas or liquid.
During the conference at which the result was announced, the Kepler team said that it had spotted some 1,094 new candidate planets.
The Kepler space telescope was designed to look at a fixed swathe of the night sky, staring intently at about 150,000 stars. The telescope is sensitive enough to see when a planet passes in front of its host star, dimming the star's light by a minuscule amount.
Kepler identifies these slight changes in starlight as candidate planets, which are then confirmed by further observations by Kepler and other telescopes in orbit and on Earth.
Kepler 22-b was one of 54 candidates reported by the Kepler team in February, and is just the first to be formally confirmed using other telescopes.
More of these "Earth 2.0" candidates are likely to be confirmed in the near future, though a redefinition of the habitable zone's boundaries has brought that number down to 48.
Kepler 22-b lies at a distance from its sun about 15% less than the distance from the Earth to the Sun, and its year takes about 290 days. However, its sun puts out about 25% less light, keeping the planet at its balmy temperature that would support the existence of liquid water.
The Kepler team had to wait for three passes of the planet before upping its status from "candidate" to "confirmed".
"Fortune smiled upon us with the detection of this planet," said William Borucki, Kepler principal investigator at Nasa's Ames Research Center.
"The first transit was captured just three days after we declared the spacecraft operationally ready. We witnessed the defining third transit over the 2010 holiday season."
The results were announced at the Kepler telescope's first science conference, alongside the staggering number of new candidate planets. The total number of candidates spotted by the telescope is now 2,326 - of which 207 are approximately Earth-sized.
In total, the results suggest that planets ranging from Earth-sized to about four times Earth's size - so-called "super-Earths" - may be more common than previously thought.
http://www.bbc.co.uk/news/science-environment-16040655 (http://www.bbc.co.uk/news/science-environment-16040655)
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:party: :party: :party:
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I bet the gravity there would get annoying real fast. I like the Kepler telescope project. :thumbup:
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Did someone say... roadtrip??
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Humans will be wiped off the face of the Earth long before any intergalactic traveling will ever be possible. Nice to dream, though.
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Temperature sounds fine and all, but what about atmospheric pressure/composition, water availability and gravity?
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Did someone say... roadtrip??
It would be awesome if we could do this.
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Did someone say... roadtrip??
It would be awesome if we could do this.
My suitcase is already packed in anticipation.
I'm just waiting for teleportation to be invented :orly:
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I like this
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Humans will be wiped off the face of the Earth long before any intergalactic traveling will ever be possible. Nice to dream, though.
Somehow, there just might be a truth to what you say this time.
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Unfortunately, I think Kepler 22-b is likely to turn out to have a run-away greenhouse effect like Venus. I'll be interested in the papers that get published once people have had time to construct models and run simulations, but based on past papers I've read on exoplanet habitability, it's a pretty borderline candidate.
The habitable zone moves outwards for planets with masses larger than Earth, due to their presumably thicker atmospheres, all else being equal. Earth is already quite close to the inner edge of the habitable zone, and has an equilibrium temperature of -18C (if it didn't have an atmosphere), while Kepler 22-b has a rather higher equilibrium temperature of -11C. If the planet is arid or if it has a thin atmosphere, it would radiate heat back into space efficiently, so the habitable zone would shift back inwards and it would have a better chance of remaining habitable, but it's more likely to have a lot of water and a thick atmosphere, or to have had lots of water at one point, before all the water boiled off into the atmosphere and then photo-dissociated with the hydrogen being lost to space and the oxygen reacting with minerals in the crust.
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Unfortunately, I think Kepler 22-b is likely to turn out to have a run-away greenhouse effect like Venus. I'll be interested in the papers that get published once people have had time to construct models and run simulations, but based on past papers I've read on exoplanet habitability, it's a pretty borderline candidate.
The habitable zone moves outwards for planets with masses larger than Earth, due to their presumably thicker atmospheres, all else being equal.
I'll grant you that I don't know much about exoplanet study, but I think the key word here is "presumably". Obviously, planets more dense than earth have the POTENTIAL to have denser atmospheres, but their mechanisms for atmosphere generation may not be the same. IIRC, the earth owes a lot of its atmosphere to the early activity of bacteria and other micro organisms that pulled nitrogen and oxygen from seawater and rocks. Until we can see the atmospheres on other exoplanets and measure their density and composition, we can only guess as to the processes that created them.
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Humans will be wiped off the face of the Earth long before any intergalactic traveling will ever be possible. Nice to dream, though.
Although you're probably right, we owe it to future generations to at least try to colonize the Galaxy.
We're the only living thing on earth that is aware that the earth will be unihabitable someday, an that there's the potential of other places in the universe to live.
After all, If the little green men figured out how to make it to Roswell, tha mean people can do it too. :smarty: :probe:
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Did someone say... roadtrip??
It would be awesome if we could do this.
My suitcase is already packed in anticipation.
I'm just waiting for teleportation to be invented :orly:
Your wait is over babe! Just step into my magic teleportation box and I'll take you to other worlds sweet thing!!! :eyebrows: :eyebrows: :eyebrows:
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Temperature sounds fine and all, but what about atmospheric pressure/composition, water availability and gravity?
not to mention terra firma
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I think it's terrific news. Amazing that they now have equipment good enough to spot planets that small.
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I think it's terrific news. Amazing that they now have equipment good enough to spot planets that small.
I have a feeling that as the technology gets better, we're going to start seeing a lot more Earth-like planets with possible life-sustaining qualities (maybe not for us, but for something).
But couldn't Earth-like planets be detected by observation of a gas giant's wobble against unseen celestial bodies in a star system? Or is that the actual current method to find smaller worlds?
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But couldn't Earth-like planets be detected by observation of a gas giant's wobble against unseen celestial bodies in a star system? Or is that the actual current method to find smaller worlds?
AFAIK, there's two methods of detecting exoplanets
1) detecting a woble in the star. This usually only finds large Jupiter type planets though.
2) detecting a slight dimming of the star. This is the method used to find earth like planets.
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I think it's terrific news. Amazing that they now have equipment good enough to spot planets that small.
I have a feeling that as the technology gets better, we're going to start seeing a lot more Earth-like planets with possible life-sustaining qualities (maybe not for us, but for something).
But couldn't Earth-like planets be detected by observation of a gas giant's wobble against unseen celestial bodies in a star system? Or is that the actual current method to find smaller worlds?
A gas giant's wobble could probably not be used for that. The oscillations are very small and they would first need to determine an orbit for the giant which could take a very long time. They would also have to take into account any other bodies affecting its orbit, most of which would be larger than the possible earth-like planet.
Not saying it can't but it seems unlikely.
I think today's observations are purely optical. They would have to be if they wanted to do a spectral analysis of the new body.
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Unfortunately, I think Kepler 22-b is likely to turn out to have a run-away greenhouse effect like Venus. I'll be interested in the papers that get published once people have had time to construct models and run simulations, but based on past papers I've read on exoplanet habitability, it's a pretty borderline candidate.
The habitable zone moves outwards for planets with masses larger than Earth, due to their presumably thicker atmospheres, all else being equal.
I'll grant you that I don't know much about exoplanet study, but I think the key word here is "presumably". Obviously, planets more dense than earth have the POTENTIAL to have denser atmospheres, but their mechanisms for atmosphere generation may not be the same. IIRC, the earth owes a lot of its atmosphere to the early activity of bacteria and other micro organisms that pulled nitrogen and oxygen from seawater and rocks. Until we can see the atmospheres on other exoplanets and measure their density and composition, we can only guess as to the processes that created them.
The nitrogen in Earth's atmosphere is derived from the volcanic outgassing of N2 and ammonia, and from cometary delivery (http://arxiv.org/pdf/0906.5221). Nitrogen-fixing bacteria remove nitrogen from the atmosphere by incorporating it into nitrogenous organic compounds; some of these are later returned to the atmosphere by denitrifying bacteria, and some is geologically sequestered (http://www.agu.org/pubs/crossref/2002/2002GB001862.shtml). Some geologically sequestered biological nitrogen is eventually returned to the atmosphere by the weathering of the rocks that contain it, but the net effect of bacteria on Earth has been to remove nitrogen from the atmosphere over geological time, with perhaps half (http://www.nature.com/ngeo/journal/v2/n12/abs/ngeo692.html) of the nitrogen in Earth's early atmosphere having been removed by bacteria and geologically sequestered so far.
The story is similar for CO2; it originates from volcanic outgassing and cometary delivery, and most of it has been removed from the atmosphere by biological activity. On Earth, there are 2 main processes that remove CO2 from the atmosphere. One is the burial of carbon-rich biological material, which removes the carbon and leaves the oxygen in the atmosphere. The other is the abiotic reaction of silicate minerals with CO2 to from carbonate minerals. This process is greatly accelerated when silicate rock is exposed to rain, which absorbs CO2 to form carbonic acid, and it occurs very slowly in the absence of water or when the rock is submerged in the oceans, where the high PH inhibits the reaction. On Earth, the removal of CO2 by the weathering of exposed silicate rock outpaces the volcanic outgassing of CO2.
On an Earth-mass planet with a global ocean or with no precipitation, CO2 removal by silicate weathering would be outpaced by the addition of CO2 by volcanic outgassing, causing CO2 to build up in the atmosphere over time. On a super-Earth, tectonic processes would be more vigorous and the volcanic outgassing of CO2 and nitrogen would be more rapid than it is here on Earth, and the increased volcanism would also result in a more rapid release of primordial water from rocks in the mantle, which means that a super-Earth is more likely to have a global ocean. These factors favour super-Earths which are further out from their stars, since they can remain at a comfortable temperature at distances which would cause global glaciation on Earth.
Planet formation is a highly non-linear, chaotic process, and the eventual conditions on a planet are sensitive to chance collisions, ejections and migrations during the formation of the planetary system, as well as on elemental abundances around a star, which are affected by the number and the types of nearby supernovae that contributed to the proto-planetary disk, and the degree of radioactive heating, which is important for the differentiation of planetary interiors, is dependent also on the period of time that's elapsed between supernova contributions and planet formation, but comparisons can be made on an all-else-being-equal basis between Earth and exoplanets with poorly constrained atmospheric conditions (in this case, only the radius and the orbital period are known; the mass is just estimated and nothing at all is known about the atmosphere).
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i remember reading somewhere a long time ago that water may not be a nesesity to live, that some scientists have done a small studies in which they reproduced the atmosphere of one of jupiters moons which is cold enough to support liquid methane and were able to re-create something that they said lead to life...
actually i remember now i saw it on TV and i was playing games on my computer so i wasnt paying attention but supposedly they have come up with results saying its "plausible" to have life living on more than liquid water.
though i am unsure of the validity of this claim and can not back up anything i said here so please take it with a grain of salt
any ways, i found that interesting so i hope you do to
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Yes, I remember reading about it too.