1000 worlds
February 3, 2011 12:06 PM Subscribe
NASAs Kepler mission has discovered over 1,100 extrasolar planet candidates. Including, "68 Earth-sized, 288 super-Earth-sized, 662 Neptune-sized, and 165 Jupiter-sized planets". 54 are found in their star's habitable zone, with five of those considered "near-Earth sized"
The discoveries will require further observations to confirm their existence. The current confirmed planet count for the Kepler mission stands at 15. The new discoveries include a system with 5 or 6 planets more tightly packed than the orbit of Mercury to the Sun. The discovery has been called "historic" and "game-changing". Until recently, Kepler detected no Earth-sized planets.
The discoveries will require further observations to confirm their existence. The current confirmed planet count for the Kepler mission stands at 15. The new discoveries include a system with 5 or 6 planets more tightly packed than the orbit of Mercury to the Sun. The discovery has been called "historic" and "game-changing". Until recently, Kepler detected no Earth-sized planets.
Maybe they've finally discovered my cat's home planet. It'd be nice to see where in the galaxy this awesome evil was bred.
posted by Kitteh at 12:10 PM on February 3, 2011 [2 favorites]
posted by Kitteh at 12:10 PM on February 3, 2011 [2 favorites]
All these worlds are yours except Cygnum-Beta-Sirius-5. Which frankly, is a bit of a dump. In a bad neighbourhood.
posted by seanyboy at 12:11 PM on February 3, 2011 [10 favorites]
posted by seanyboy at 12:11 PM on February 3, 2011 [10 favorites]
Woo, M-class planets!
posted by charred husk at 12:12 PM on February 3, 2011 [1 favorite]
posted by charred husk at 12:12 PM on February 3, 2011 [1 favorite]
So I assume we're focusing our radio telescopes on them, now.
posted by empath at 12:13 PM on February 3, 2011 [2 favorites]
posted by empath at 12:13 PM on February 3, 2011 [2 favorites]
What winds up my imagination more than an Earth-sized planet in the habitable zone is the idea of these giant, mega-Jupiters orbiting stars at a distance closer than Mercury. That's such an alien concept to the blue print we have in our own solar system, and it just messes with my mind.
posted by SNWidget at 12:14 PM on February 3, 2011 [3 favorites]
posted by SNWidget at 12:14 PM on February 3, 2011 [3 favorites]
What messes with my mind is that we can actually detect planets orbiting other stars. Despite all the nastiness, we humans really are awesome sometimes.
posted by brundlefly at 12:22 PM on February 3, 2011 [1 favorite]
posted by brundlefly at 12:22 PM on February 3, 2011 [1 favorite]
ALL THESE WORDS ARE YOURS, IF YOU CAN REACH THEM, NAH-NAH.
posted by Brandon Blatcher at 12:28 PM on February 3, 2011 [11 favorites]
posted by Brandon Blatcher at 12:28 PM on February 3, 2011 [11 favorites]
Can someone explain something that confuses me a bit about this whole project (I have high-school level astronomy knowledge...)
My understanding is these are detected by changes in light reaching us from the stars as the planet passes in front of them. Why are all these planets lined up in such a way such that their orbit is between us and their star? Do solar system planes usually line up very well with the plane of the galaxy, so this is not unlikely? Or are we assuming that there are proportionally as many planets with all the orbits that wouldn't cross their stars from our perspective?
posted by brainmouse at 12:28 PM on February 3, 2011
My understanding is these are detected by changes in light reaching us from the stars as the planet passes in front of them. Why are all these planets lined up in such a way such that their orbit is between us and their star? Do solar system planes usually line up very well with the plane of the galaxy, so this is not unlikely? Or are we assuming that there are proportionally as many planets with all the orbits that wouldn't cross their stars from our perspective?
posted by brainmouse at 12:28 PM on February 3, 2011
We should send them beer.
posted by Mister_A at 12:28 PM on February 3, 2011 [2 favorites]
posted by Mister_A at 12:28 PM on February 3, 2011 [2 favorites]
The optimist proclaims that we live in the best of all possible worlds; and the pessimist fears this is true.
-Todd Lokken James Branch Cabell
posted by blue_beetle at 12:29 PM on February 3, 2011
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posted by blue_beetle at 12:29 PM on February 3, 2011
Some comments:
"This is exciting, if not a bit sad since none of us living today will probably know much more about these planets other than they probably exist."
Not true at all. The technical obstacles to determining the composition, system architecture, formation mechanisms, and, yes, whether or not there is life on extrasolar planets are daunting problems, but far from insurmountable ones. And they are, for the most part, technical obstacles, not technological ones -- we already know how to do most of this, it's a matter of spending the time, money, and resources to build the necessary equipment and conduct the necessary research. Well within a human lifetime, we should be able to tell the *weather* on extrasolar planets.
"So I assume we're focusing our radio telescopes on them, now."
Well, that kind of thing will probably wait until it's determined which of these are confirmed planets rather than just candidate planets. Also, so far infra-red has been more useful than radio for this kind of thing.
posted by kyrademon at 12:31 PM on February 3, 2011 [1 favorite]
"This is exciting, if not a bit sad since none of us living today will probably know much more about these planets other than they probably exist."
Not true at all. The technical obstacles to determining the composition, system architecture, formation mechanisms, and, yes, whether or not there is life on extrasolar planets are daunting problems, but far from insurmountable ones. And they are, for the most part, technical obstacles, not technological ones -- we already know how to do most of this, it's a matter of spending the time, money, and resources to build the necessary equipment and conduct the necessary research. Well within a human lifetime, we should be able to tell the *weather* on extrasolar planets.
"So I assume we're focusing our radio telescopes on them, now."
Well, that kind of thing will probably wait until it's determined which of these are confirmed planets rather than just candidate planets. Also, so far infra-red has been more useful than radio for this kind of thing.
posted by kyrademon at 12:31 PM on February 3, 2011 [1 favorite]
Why are all these planets lined up in such a way such that their orbit is between us and their star? Do solar system planes usually line up very well with the plane of the galaxy, so this is not unlikely? Or are we assuming that there are proportionally as many planets with all the orbits that wouldn't cross their stars from our perspective?
Your second guess is correct. There are many planets orbiting stars with orbits that do not line up with our line of sight. Kepler was only designed to detect those that do occlude their star from our perspective.
posted by Salvor Hardin at 12:32 PM on February 3, 2011 [2 favorites]
Your second guess is correct. There are many planets orbiting stars with orbits that do not line up with our line of sight. Kepler was only designed to detect those that do occlude their star from our perspective.
posted by Salvor Hardin at 12:32 PM on February 3, 2011 [2 favorites]
[...] across the gulf of space, intellects vast and cool and unsympathetic regarded our planet with envious eyes and slowly, and surely, drew their plans against us.
-- HG Wells
posted by Old'n'Busted at 12:33 PM on February 3, 2011 [2 favorites]
-- HG Wells
posted by Old'n'Busted at 12:33 PM on February 3, 2011 [2 favorites]
Brainmouse,
From the "54 are found in their planet's habitable zone" link:
[UPDATE: the transit method employed by Kepler only finds planets that happen to have orbits edge-on as seen from Earth. That means it doesn't even see planets that have orbits tilted with respect to us, meaning that this estimate is almost certainly too low.]
posted by colfax at 12:34 PM on February 3, 2011 [1 favorite]
From the "54 are found in their planet's habitable zone" link:
[UPDATE: the transit method employed by Kepler only finds planets that happen to have orbits edge-on as seen from Earth. That means it doesn't even see planets that have orbits tilted with respect to us, meaning that this estimate is almost certainly too low.]
posted by colfax at 12:34 PM on February 3, 2011 [1 favorite]
Brainmouse -- That is why the Kepler mission is designed to look at around 100,000 stars. It's probably detecting only 1 to 10 percent of the number of planets actually in that region.
posted by kyrademon at 12:35 PM on February 3, 2011
posted by kyrademon at 12:35 PM on February 3, 2011
What messes with my mind is that we can actually detect planets orbiting other stars.
What I find impressive is that less than twenty years ago we knew of nine* planets, all orbiting the same star that we do. Now less than 2% of all the planets we are aware of are in our system.
*Yeah, I said it.
posted by ricochet biscuit at 12:36 PM on February 3, 2011 [3 favorites]
What I find impressive is that less than twenty years ago we knew of nine* planets, all orbiting the same star that we do. Now less than 2% of all the planets we are aware of are in our system.
*Yeah, I said it.
posted by ricochet biscuit at 12:36 PM on February 3, 2011 [3 favorites]
This is just the beginning. This release covers just over four months of data taking, and they have over 1100 candidates? Even at a 10% confirmation ratio, that's 110 planets, with one of our first dedicated planetary search instruments.
The actual confirmation rate is more likely to be near 90%, not 10% -- so over 900 planets. The field of view of Kepler? Hold your fist out at arms length. The coverage is 120°2 -- the entire sky is about 41,500°2
What Kepler has done is told us, quite simple, that planetary systems are not rare at all. It's estimate that Kepler is watching 145,000 main sequence stars, and in four months, has candidates around 997 of them. That's .6% of the stars in view. If we assume that percentage, it means that there are 600 million to 2.4 billion planetary systems in our Galaxy.
Just amazing. And we can be certain that Kepler won't see all of the planetary systems in its field of view -- any system where the planets don't eclipse the star from our point of view is completely undetectable by Kepler. If a copy of our system was placed in the field of view, with only the Earth in it's normal orbit, there's a .47% chance that the ecliptic would be in plane enough for us to observe the transit and detect the Earth. This chance varies some by the size of the planet and a great deal by the distance -- close in planets will be much more likely to have visible transits. Assume that 5% of the systems with planets are correctly aligned so that we see transits.
That means, now, that those 600M to 2.4B systems represent 5% of the total, and we're now looking at 12 billion to 48 billion planetary systems in our Galaxy -- out of a total of 100 to 400 billion stars. Assume half the lower number, 6 billion planetary systems per galaxy. Current estimates of number of galaxies in the observable universe is on the order of 150 billion, so at 6 billion planetary systems per, that' s 900 billion planetary systems in the universe.
And that's a lower bound! A trillion planetary systems is almost a certainty, indeed, I think the number is easily ten times that, but that will need more data. But a trillion, sure?
Kepler may have discovered about 19 planets confirmed, and around a thousand other candidates, but what it's really discovered is at least a trillion of them. We can't see them -- yet -- but we know they're there.
If we're the only planet with intelligent life, then the universe is playing a joke on us.
posted by eriko at 12:37 PM on February 3, 2011 [83 favorites]
The actual confirmation rate is more likely to be near 90%, not 10% -- so over 900 planets. The field of view of Kepler? Hold your fist out at arms length. The coverage is 120°2 -- the entire sky is about 41,500°2
What Kepler has done is told us, quite simple, that planetary systems are not rare at all. It's estimate that Kepler is watching 145,000 main sequence stars, and in four months, has candidates around 997 of them. That's .6% of the stars in view. If we assume that percentage, it means that there are 600 million to 2.4 billion planetary systems in our Galaxy.
Just amazing. And we can be certain that Kepler won't see all of the planetary systems in its field of view -- any system where the planets don't eclipse the star from our point of view is completely undetectable by Kepler. If a copy of our system was placed in the field of view, with only the Earth in it's normal orbit, there's a .47% chance that the ecliptic would be in plane enough for us to observe the transit and detect the Earth. This chance varies some by the size of the planet and a great deal by the distance -- close in planets will be much more likely to have visible transits. Assume that 5% of the systems with planets are correctly aligned so that we see transits.
That means, now, that those 600M to 2.4B systems represent 5% of the total, and we're now looking at 12 billion to 48 billion planetary systems in our Galaxy -- out of a total of 100 to 400 billion stars. Assume half the lower number, 6 billion planetary systems per galaxy. Current estimates of number of galaxies in the observable universe is on the order of 150 billion, so at 6 billion planetary systems per, that' s 900 billion planetary systems in the universe.
And that's a lower bound! A trillion planetary systems is almost a certainty, indeed, I think the number is easily ten times that, but that will need more data. But a trillion, sure?
Kepler may have discovered about 19 planets confirmed, and around a thousand other candidates, but what it's really discovered is at least a trillion of them. We can't see them -- yet -- but we know they're there.
If we're the only planet with intelligent life, then the universe is playing a joke on us.
posted by eriko at 12:37 PM on February 3, 2011 [83 favorites]
As for where to point the radio telescopes, the next step ought to be to use this data to improve our methodologies for determining which types of stars are likely to host rocky planets in the habitable zone. Then scan the skies for clusters of those types of stars... then point radio telescopes at them, and engage the Allen Array.
The nerd in me also wants Kepler to check out Tau Sagittari, which is the closest star to the region of space that the "Wow" signal may have originated from (if not terrestrial interference).
posted by BobbyVan at 12:37 PM on February 3, 2011 [1 favorite]
The nerd in me also wants Kepler to check out Tau Sagittari, which is the closest star to the region of space that the "Wow" signal may have originated from (if not terrestrial interference).
posted by BobbyVan at 12:37 PM on February 3, 2011 [1 favorite]
We should send them beer.
Nah, we could never agree on which one to send.
posted by elsietheeel at 12:38 PM on February 3, 2011
Nah, we could never agree on which one to send.
posted by elsietheeel at 12:38 PM on February 3, 2011
Kepler may have discovered about 19 planets confirmed, and around a thousand other candidates, but what it's really discovered is at least a trillion of them. We can't see them -- yet -- but we know they're there.
Wouldn't you know it, the Mormons were right after all.
posted by theodolite at 12:38 PM on February 3, 2011 [1 favorite]
Wouldn't you know it, the Mormons were right after all.
posted by theodolite at 12:38 PM on February 3, 2011 [1 favorite]
Brandon Blatcher: "ALL THESE WORDS ARE YOURS, IF YOU CAN REACH THEM, NAH-NAH."
I was talking to my gf last night, and did a *very* rough calculation. Basing it off of what I read about the Helios solar observatory (and I realize that's not a sustained speed). That the fastest manmade object has only reached 1/6000 the speed of light. So even if we COULD sustain that speed, it would take us 6000 times longer than the "light-years" to get anywhere anytime soon.
Of course, I'm not even considering relativistic time dilation, though.
posted by symbioid at 12:40 PM on February 3, 2011
I was talking to my gf last night, and did a *very* rough calculation. Basing it off of what I read about the Helios solar observatory (and I realize that's not a sustained speed). That the fastest manmade object has only reached 1/6000 the speed of light. So even if we COULD sustain that speed, it would take us 6000 times longer than the "light-years" to get anywhere anytime soon.
Of course, I'm not even considering relativistic time dilation, though.
posted by symbioid at 12:40 PM on February 3, 2011
If we're the only planet with intelligent life, then the universe is playing a joke on us.
As I have said for years: either we are the only ones here or we are not. Either way, it is staggering.
posted by ricochet biscuit at 12:41 PM on February 3, 2011 [17 favorites]
As I have said for years: either we are the only ones here or we are not. Either way, it is staggering.
posted by ricochet biscuit at 12:41 PM on February 3, 2011 [17 favorites]
Well within a human lifetime, we should be able to tell the *weather* on extrasolar planets.
Pardon my ignorance, but would it be technically possible to build an optical telescope (orbiting or otherwise) that could actually look at these planets the way a dime store Tasco can see Saturn or Jupiter? Or is there some sort of technical limit to the optics that would make this impossible?
Let's say we found a couple planets that seemed like they'd be the most likely to be Earth-like and we designed the scope to look at just one of them. Let's assume we had all the money and support we needed.
posted by bondcliff at 12:42 PM on February 3, 2011
Pardon my ignorance, but would it be technically possible to build an optical telescope (orbiting or otherwise) that could actually look at these planets the way a dime store Tasco can see Saturn or Jupiter? Or is there some sort of technical limit to the optics that would make this impossible?
Let's say we found a couple planets that seemed like they'd be the most likely to be Earth-like and we designed the scope to look at just one of them. Let's assume we had all the money and support we needed.
posted by bondcliff at 12:42 PM on February 3, 2011
So even if we COULD sustain that speed, it would take us 6000 times longer than the "light-years" to get anywhere anytime soon.
Ok, let's load up the Space Arks!
posted by Brandon Blatcher at 12:44 PM on February 3, 2011 [1 favorite]
Ok, let's load up the Space Arks!
posted by Brandon Blatcher at 12:44 PM on February 3, 2011 [1 favorite]
As I have said for years: either we are the only ones here or we are not. Either way, it is staggering.
Arthur? Is that you? You're alive!
posted by bondcliff at 12:45 PM on February 3, 2011 [2 favorites]
Arthur? Is that you? You're alive!
posted by bondcliff at 12:45 PM on February 3, 2011 [2 favorites]
My understanding is these are detected by changes in light reaching us from the stars as the planet passes in front of them. Why are all these planets lined up in such a way such that their orbit is between us and their star? Do solar system planes usually line up very well with the plane of the galaxy, so this is not unlikely? Or are we assuming that there are proportionally as many planets with all the orbits that wouldn't cross their stars from our perspective?
I would think that conservation of angular momentum would make it more likely than not that any given star would be aligned with the galactic plane, for the same reason that most planets in the solar system are aligned with the rotation of the sun.
posted by empath at 12:47 PM on February 3, 2011 [1 favorite]
I would think that conservation of angular momentum would make it more likely than not that any given star would be aligned with the galactic plane, for the same reason that most planets in the solar system are aligned with the rotation of the sun.
posted by empath at 12:47 PM on February 3, 2011 [1 favorite]
My guess is that you are correct in the statistical sense, empath; but it seems likely that typical small divergences from the solar plane would render the planetary objects invisible to the Kepler optics.
posted by Mister_A at 12:51 PM on February 3, 2011
posted by Mister_A at 12:51 PM on February 3, 2011
Pardon my ignorance, but would it be technically possible to build an optical telescope (orbiting or otherwise) that could actually look at these planets the way a dime store Tasco can see Saturn or Jupiter? Or is there some sort of technical limit to the optics that would make this impossible?
I can't for the life of me remember the name of the proposed telescope, and I'm not having great luck looking it up... but I went to NASA JPL's open house in 2009 and there was a big public viewing of some pieces of a telescope project that would have done just that. The idea was that they wouldn't have a single telescope, but rather an array of some number of big telescopes, I want to say something like 8 or 16 of them, all floating in formation in space. They said that with that kind of telescope power they would be able to see individual forests -- or whatever they have -- on other planets, but I can't remember how far out that would be the case. It might have just been within the solar system; I can't quite remember. They said the tentative plan was that they'd be launched, uh, somewhere in 2014 or 2016 or something, but projects get scrapped or postponed all the time.
My husband works there, but on radar stuff so he wouldn't necessarily remember the name. I'll ask him when he gets home, though.
posted by Nattie at 12:56 PM on February 3, 2011 [1 favorite]
I can't for the life of me remember the name of the proposed telescope, and I'm not having great luck looking it up... but I went to NASA JPL's open house in 2009 and there was a big public viewing of some pieces of a telescope project that would have done just that. The idea was that they wouldn't have a single telescope, but rather an array of some number of big telescopes, I want to say something like 8 or 16 of them, all floating in formation in space. They said that with that kind of telescope power they would be able to see individual forests -- or whatever they have -- on other planets, but I can't remember how far out that would be the case. It might have just been within the solar system; I can't quite remember. They said the tentative plan was that they'd be launched, uh, somewhere in 2014 or 2016 or something, but projects get scrapped or postponed all the time.
My husband works there, but on radar stuff so he wouldn't necessarily remember the name. I'll ask him when he gets home, though.
posted by Nattie at 12:56 PM on February 3, 2011 [1 favorite]
So, ok, if we have all this mass now potentially in planets that we didn't know of before, what were we estimating in general for mass of the universe that included potential planets. Are planets more numerous than expected? If so, does this fundamentally alter our previous estimates of mass? Does this help explain Dark Matter? I think the answer is "no", but I can't remember why that would be the case. Anyone?
posted by symbioid at 1:01 PM on February 3, 2011
posted by symbioid at 1:01 PM on February 3, 2011
A new life awaits you in the Off-world colonies! A chance to begin again in a golden land of opportunity and adventure!
posted by Gelatin at 1:02 PM on February 3, 2011 [7 favorites]
posted by Gelatin at 1:02 PM on February 3, 2011 [7 favorites]
I can't for the life of me remember the name of the proposed telescope . . .
Terrestrial Planet Finder?
posted by IvoShandor at 1:02 PM on February 3, 2011 [1 favorite]
Terrestrial Planet Finder?
posted by IvoShandor at 1:02 PM on February 3, 2011 [1 favorite]
I can't for the life of me remember the name of the proposed telescope
Sounds like the now-scrapped Darwin:
Sounds like the now-scrapped Darwin:
Darwin was a suggested ESA Cornerstone mission which would have involved a constellation of four to nine spacecraft designed to directly detect Earth-like planets orbiting nearby stars and search for evidence of life on these planets.posted by BobbyVan at 1:06 PM on February 3, 2011
Advanced Technology Large-Aperture Space Telescope (ATLAST)?
posted by T.D. Strange at 1:06 PM on February 3, 2011
posted by T.D. Strange at 1:06 PM on February 3, 2011
ESA (European Space Agency) had an array of optical observatories called Darwin to do this. I thought I had heard the program was halted on phase A development for lack of funds or priority. Someone else may know better than I.
There is an instrument being developed by a small company in Maryland (in Goddard's orbit) for looking specifically at exoplanets, its called a 'nulling interferometer'. JPL is involved in that one, somehow. I'd love to know more about that. I don't believe its a part of any actual mission as of yet.
posted by newdaddy at 1:06 PM on February 3, 2011
There is an instrument being developed by a small company in Maryland (in Goddard's orbit) for looking specifically at exoplanets, its called a 'nulling interferometer'. JPL is involved in that one, somehow. I'd love to know more about that. I don't believe its a part of any actual mission as of yet.
posted by newdaddy at 1:06 PM on February 3, 2011
It seems like there's supposed to be a shit-load of dark matter, way more than even common planetary systems could account for. Wolfram tells me that the total mass of all the planets in our solar system is several orders of magnitude less than the mass of the sun. So I think you need other explanations for dark matter. I don't know where the debate is leaning these days on MACHOs vs more exotic non-baryonic forms of matter.
posted by Mister_A at 1:08 PM on February 3, 2011
posted by Mister_A at 1:08 PM on February 3, 2011
Are astronomers looking at our closest stars -- Alpha Centauri AB and Proxima Centauri?
posted by Cool Papa Bell at 1:17 PM on February 3, 2011
posted by Cool Papa Bell at 1:17 PM on February 3, 2011
My bags are packed!
posted by cjorgensen at 1:26 PM on February 3, 2011 [2 favorites]
posted by cjorgensen at 1:26 PM on February 3, 2011 [2 favorites]
I'm thinking it must be the TPF, although that's not entirely how I remembered it. Not sure if they changed it since then, or my memory is wrong, or it's something else altogether. The few things that give me pause are that they were talking about it as a current thing in 2009, but it looks like very little has been done with TPF since 2008 or earlier, and then I could have sworn the telescopes in formation were optical and not infrared. But the projected launch dates seem to correspond and it's JPL's project, so it seems likely that was it. They could have been showing it at the open house to rekindle enthusiasm and I could have misremembered the infrared part.
It's definitely not ATLAST because that's not a NASA project. It's definitely not Darwin for the same reason and because Darwin was scrapped in 2007, but it does sound like a similar idea. Anyway, apparently it's possible to see stuff much better than we do now, it's largely a question of funding.
posted by Nattie at 1:35 PM on February 3, 2011
It's definitely not ATLAST because that's not a NASA project. It's definitely not Darwin for the same reason and because Darwin was scrapped in 2007, but it does sound like a similar idea. Anyway, apparently it's possible to see stuff much better than we do now, it's largely a question of funding.
posted by Nattie at 1:35 PM on February 3, 2011
Does this help explain Dark Matter?
No. Not even close, actually. There's ~5 times more dark matter in the Universe than there is baryonic (normal) matter. So the mass contributed by planets would have to be on the order of all the galactic matter we can already see. The numbers we're talking about aren't even close to that.
posted by auto-correct at 1:36 PM on February 3, 2011
No. Not even close, actually. There's ~5 times more dark matter in the Universe than there is baryonic (normal) matter. So the mass contributed by planets would have to be on the order of all the galactic matter we can already see. The numbers we're talking about aren't even close to that.
posted by auto-correct at 1:36 PM on February 3, 2011
Wow - I thought it was a bit larger, but I didn't realize there was a need for that much dark matter.
posted by symbioid at 1:38 PM on February 3, 2011
posted by symbioid at 1:38 PM on February 3, 2011
Actually our own solar system is about 60 degrees out of whack with the galactic plane. I suspect the plane of a forming solar system's ecliptic is influenced a lot more by the shock waves that start the gas compressing than the galaxy's rotation.
posted by localroger at 1:38 PM on February 3, 2011 [2 favorites]
posted by localroger at 1:38 PM on February 3, 2011 [2 favorites]
Nattie, there were a couple very conceptual projects on the roadmap past TPF that weren't much past the glimmer-of-a-scientist's-eye stage called Life Finder and Planet Imager. Ostensibly bookmarked for about a decade or so after TPF.... The only remaining reference to these is in This PDF, and you might have seen a prettied-up version of the graph on page 7.
posted by chimaera at 1:46 PM on February 3, 2011
posted by chimaera at 1:46 PM on February 3, 2011
"... would it be technically possible to build an optical telescope (orbiting or otherwise) that could actually look at these planets the way a dime store Tasco can see Saturn or Jupiter? Or is there some sort of technical limit to the optics that would make this impossible?"
Impossible, no. Friggin' difficult, yes.
So. Pre-Kepler, the vast majority of extrasolar planets were detected by the radial velocity method -- you check a star to see if it's wobbling ever so slightly because a planet is orbiting it. Great method for spotting planets; doesn't really tell you all that much about them other than that they're there. You can probably get the mass and the distance.
To get more than that, you need photons. Information from the planet itself. Transit, which Kepler uses, gets you some of that. It's nifty. You look at the star dim, figure out how it's dimming, you start to be able to say stuff about the planet's atmosphere, the composition, the size. Great stuff.
But transit, as has been pointed out, only is able to see maybe 1 to 10 percent of all planets. And that brings us to what you want to do, a method that's just now starting to bear fruit -- direct detection. Get a picture of the planet itself.
It's only just starting to bear fruit because it's really, really hard, mostly for two reasons. First, planets are tiny, faint objects orbiting around massive, bright objects. So it's kind of like trying to take a photograph of a fly buzzing around a lamppost in Boston ... from the moon. So you want really, really sensitive instruments, big giant mirrors that collect as much light as possible, so you have a chance of seeing that faint little planet, and then you want to somehow get *rid* of all the starlight you *don't* want so you have a chance of seeing it. That's why you mess around with nulling interferometry and Lyot coronographs and all kinds of stuff like that -- to get rid of the starlight. (There's also the problem of trying to do this through the Earth's atmosphere, if you're using a ground-based rather than a space-based telescope, which is why you mess around with adaptive optics that correct for the whole damn inconsistent atmosphere.)
Anyway, once you've done that, you generally get a beautiful picture of ... speckles. Lots and lots of little speckles. That do a remarkable job of imitating planets.
See, no instrument is absolutely 100% perfect. They have little imperfections that make little flecks of reflected starlight. For a lot of astronomy, this presents no problem. For direct detection of extrasolar planets, it's a big problem.
So now you have to get rid of all the speckles -- but *without* getting rid of the planet you wanted to look at in the first place. If it's there. So you do clever little tricksy things with the differences between planets and speckles to subtract out the speckles and leave real objects behind. How they move across the sky, what happens when you take images through two different filters and compare, that kind of thing.
Once you've done that -- THEN you have yourself a picture of a planet orbiting another star! Cute little dot in your image. That's when you get to say, yee-ha! What's the mass? What's the composition? Is there variability indicating moving clouds? Let's do spectrography! What's the atmosphere made of?
Basically, that's your dime-store telescope aimed at Jupiter there, but there were a few more hoops to jump through.
Seven of those little suckers have been directly imaged so far now, up from zero just a few years ago.
And counting.
posted by kyrademon at 1:51 PM on February 3, 2011 [11 favorites]
Impossible, no. Friggin' difficult, yes.
So. Pre-Kepler, the vast majority of extrasolar planets were detected by the radial velocity method -- you check a star to see if it's wobbling ever so slightly because a planet is orbiting it. Great method for spotting planets; doesn't really tell you all that much about them other than that they're there. You can probably get the mass and the distance.
To get more than that, you need photons. Information from the planet itself. Transit, which Kepler uses, gets you some of that. It's nifty. You look at the star dim, figure out how it's dimming, you start to be able to say stuff about the planet's atmosphere, the composition, the size. Great stuff.
But transit, as has been pointed out, only is able to see maybe 1 to 10 percent of all planets. And that brings us to what you want to do, a method that's just now starting to bear fruit -- direct detection. Get a picture of the planet itself.
It's only just starting to bear fruit because it's really, really hard, mostly for two reasons. First, planets are tiny, faint objects orbiting around massive, bright objects. So it's kind of like trying to take a photograph of a fly buzzing around a lamppost in Boston ... from the moon. So you want really, really sensitive instruments, big giant mirrors that collect as much light as possible, so you have a chance of seeing that faint little planet, and then you want to somehow get *rid* of all the starlight you *don't* want so you have a chance of seeing it. That's why you mess around with nulling interferometry and Lyot coronographs and all kinds of stuff like that -- to get rid of the starlight. (There's also the problem of trying to do this through the Earth's atmosphere, if you're using a ground-based rather than a space-based telescope, which is why you mess around with adaptive optics that correct for the whole damn inconsistent atmosphere.)
Anyway, once you've done that, you generally get a beautiful picture of ... speckles. Lots and lots of little speckles. That do a remarkable job of imitating planets.
See, no instrument is absolutely 100% perfect. They have little imperfections that make little flecks of reflected starlight. For a lot of astronomy, this presents no problem. For direct detection of extrasolar planets, it's a big problem.
So now you have to get rid of all the speckles -- but *without* getting rid of the planet you wanted to look at in the first place. If it's there. So you do clever little tricksy things with the differences between planets and speckles to subtract out the speckles and leave real objects behind. How they move across the sky, what happens when you take images through two different filters and compare, that kind of thing.
Once you've done that -- THEN you have yourself a picture of a planet orbiting another star! Cute little dot in your image. That's when you get to say, yee-ha! What's the mass? What's the composition? Is there variability indicating moving clouds? Let's do spectrography! What's the atmosphere made of?
Basically, that's your dime-store telescope aimed at Jupiter there, but there were a few more hoops to jump through.
Seven of those little suckers have been directly imaged so far now, up from zero just a few years ago.
And counting.
posted by kyrademon at 1:51 PM on February 3, 2011 [11 favorites]
Wow, I didn't know we had directly imaged ANY extrasolar planets (ESP).
posted by Mister_A at 1:56 PM on February 3, 2011 [1 favorite]
posted by Mister_A at 1:56 PM on February 3, 2011 [1 favorite]
Wow, I didn't know we had directly imaged ANY extrasolar planets (ESP).
Yeah me too—kyrademon, can we see any of that online?
posted by dubitable at 2:09 PM on February 3, 2011
Yeah me too—kyrademon, can we see any of that online?
posted by dubitable at 2:09 PM on February 3, 2011
Pardon my ignorance, but would it be technically possible to build an optical telescope (orbiting or otherwise) that could actually look at these planets the way a dime store Tasco can see Saturn or Jupiter? Or is there some sort of technical limit to the optics that would make this impossible?
There is a fundamental limit to the resolution that can be achieved by an optical system (the diffraction limit). The finest structures you can resolve have an angular size that scales like the wavelength of light divided by the diameter of the imaging lens/mirror: in other words, a bigger mirror lets you resolve smaller-scale things.
So the answer to your question is sort of "yes," though the telescope would have to be "big." To figure out how big, note that an Earth-like planet (r ~ 6000 km) floating, say, a parsec away (d ~ 3d13 km) will have an angular size of about one twenty-thousandth of an arsecond (4.3d-5 arcsec). (I'm talking here about actually resolving the surface of the planet, like you can for, say, Jupiter, not just determining that it's there.) For comparison, Hubble can resolve things at about the 0.1 arcsecond level; to steal a comparison from Wikipedia, a one-mile long line painted on the moon would appear to be about an arcsecond long. So to fully resolve that Earth-like planet in our own relative backyard, you need something more than a thousand times larger than Hubble (which has a diameter of a couple meters).
This is the main reason no one is seriously advocating building a single lens/mirror that could image the surfaces of distant planets. The best idea is to cheat, by building an array of telescopes that together mimic the action of a single, much larger scope -- an interferometer. You'd need to do it in space, so you're talking about an array of telescopes flying in formation, pretending to be a telescope roughly the size of the Earth. That was basically the idea of the "Terrestrial Planet Imager," but it is a long way off.
(There are a few other details to contend with, too -- like the fact that planets tend to orbit around stars that are much, much brighter than the planets themselves. So just "resolving" the planet isn't quite enough -- you also need to be able to distinguish the light of the planet from that of the enormously brighter star just next to it.)
tl;dr summary: yes, but it's really, really hard. I think it will happen in my lifetime, but I'm pretty young.
posted by chalkbored at 2:10 PM on February 3, 2011 [5 favorites]
There is a fundamental limit to the resolution that can be achieved by an optical system (the diffraction limit). The finest structures you can resolve have an angular size that scales like the wavelength of light divided by the diameter of the imaging lens/mirror: in other words, a bigger mirror lets you resolve smaller-scale things.
So the answer to your question is sort of "yes," though the telescope would have to be "big." To figure out how big, note that an Earth-like planet (r ~ 6000 km) floating, say, a parsec away (d ~ 3d13 km) will have an angular size of about one twenty-thousandth of an arsecond (4.3d-5 arcsec). (I'm talking here about actually resolving the surface of the planet, like you can for, say, Jupiter, not just determining that it's there.) For comparison, Hubble can resolve things at about the 0.1 arcsecond level; to steal a comparison from Wikipedia, a one-mile long line painted on the moon would appear to be about an arcsecond long. So to fully resolve that Earth-like planet in our own relative backyard, you need something more than a thousand times larger than Hubble (which has a diameter of a couple meters).
This is the main reason no one is seriously advocating building a single lens/mirror that could image the surfaces of distant planets. The best idea is to cheat, by building an array of telescopes that together mimic the action of a single, much larger scope -- an interferometer. You'd need to do it in space, so you're talking about an array of telescopes flying in formation, pretending to be a telescope roughly the size of the Earth. That was basically the idea of the "Terrestrial Planet Imager," but it is a long way off.
(There are a few other details to contend with, too -- like the fact that planets tend to orbit around stars that are much, much brighter than the planets themselves. So just "resolving" the planet isn't quite enough -- you also need to be able to distinguish the light of the planet from that of the enormously brighter star just next to it.)
tl;dr summary: yes, but it's really, really hard. I think it will happen in my lifetime, but I'm pretty young.
posted by chalkbored at 2:10 PM on February 3, 2011 [5 favorites]
Seven directly imaged planets:
Fomalhaut B, in its beautiful dust disk (the planet is the little dot towards the lower left.)
HR 8799 B, C, D & E
Beta Pic B
1RXS J160929.1-210524 b (this has been confirmed as a planet, since this 2008 link is still identifying it as just a candidate.)
posted by kyrademon at 2:15 PM on February 3, 2011 [9 favorites]
Fomalhaut B, in its beautiful dust disk (the planet is the little dot towards the lower left.)
HR 8799 B, C, D & E
Beta Pic B
1RXS J160929.1-210524 b (this has been confirmed as a planet, since this 2008 link is still identifying it as just a candidate.)
posted by kyrademon at 2:15 PM on February 3, 2011 [9 favorites]
Thanks a lot, NASA. I've been freeloading WiFi off of Kepler-11 for the past six months,* ever since Comcast went out.
Now everyone's going to hop on it and I'll never finish downloading that torrent of TLC's Alien Ovipositor.
* Come find me. I'm I4OneWelcome, team MeFi, on the Class-M Planet Invasion and Subjugation SimNet.**
** I'm so tired of being teabagged by pipsqueak low-lag gas-phase campers and could use some backup.
posted by zippy at 2:21 PM on February 3, 2011
Now everyone's going to hop on it and I'll never finish downloading that torrent of TLC's Alien Ovipositor.
* Come find me. I'm I4OneWelcome, team MeFi, on the Class-M Planet Invasion and Subjugation SimNet.**
** I'm so tired of being teabagged by pipsqueak low-lag gas-phase campers and could use some backup.
posted by zippy at 2:21 PM on February 3, 2011
Just in case this wasn't obvious: what I was talking about was actually resolving the planetary surface itself, not its separation from the host star. The latter we can do (barely, but beautifully): see kyrademon's collection of images. The former is still a ways off. (The Earth is a lot smaller than the distance between the Earth and the Sun.)
posted by chalkbored at 2:24 PM on February 3, 2011
posted by chalkbored at 2:24 PM on February 3, 2011
This could be good, because fighting amongst ourselves is getting kind of boring.
posted by rocket88 at 2:40 PM on February 3, 2011 [2 favorites]
posted by rocket88 at 2:40 PM on February 3, 2011 [2 favorites]
I went to a talk about exoplanets today, and someone said "there were only [small number] of exoplanets known before today", as if everyone knew what that meant. Not being an astronomer, I didn't. This clears that up.
posted by madcaptenor at 3:41 PM on February 3, 2011
posted by madcaptenor at 3:41 PM on February 3, 2011
I'm still hoping that there is another Earth, and it will provide for a better conclusion with Starbuck.
Yes, she'll be married to Apollo.
posted by Brandon Blatcher at 5:13 PM on February 3, 2011
Yes, she'll be married to Apollo.
posted by Brandon Blatcher at 5:13 PM on February 3, 2011
HR8799 has a magnitude of 6, which means that in excellent dark sky conditions it can be viewed with the naked eye. I am so looking for it tonight.
Ahh, except I can't see it in summer in Australia... poo.
posted by wilful at 5:59 PM on February 3, 2011
Ahh, except I can't see it in summer in Australia... poo.
posted by wilful at 5:59 PM on February 3, 2011
For those interested further, a scientist working on Kepler has an AMA (As Me Anything) thread over on Reddit.
posted by jet_manifesto at 6:17 PM on February 3, 2011 [3 favorites]
posted by jet_manifesto at 6:17 PM on February 3, 2011 [3 favorites]
Anyone who studies the incredible variety of life on this planet, the amazing extremes to which life will adapt and flourish, and somehow still thinks that we're the only planet with life on it, is either ignorant or in some deep, deep denial.
posted by dbiedny at 6:28 PM on February 3, 2011 [1 favorite]
posted by dbiedny at 6:28 PM on February 3, 2011 [1 favorite]
Oh great, now it'll all be starbucks and forever 21. Sheesh.
I hear Tau Ceti is still pretty chill if you don't mind brain worms.
posted by The Whelk at 9:06 PM on February 3, 2011
I hear Tau Ceti is still pretty chill if you don't mind brain worms.
posted by The Whelk at 9:06 PM on February 3, 2011
This is one of the most exciting days a 12-year-old me could have imagined. It's pretty fucking great as a 46-year-old, too, except I fear I may be dead before we get to the next plateau and find life.
Get to work, stem cell researchers! I want to live for 1000 years, goddamn it.
posted by stavrosthewonderchicken at 3:47 AM on February 4, 2011 [6 favorites]
Get to work, stem cell researchers! I want to live for 1000 years, goddamn it.
posted by stavrosthewonderchicken at 3:47 AM on February 4, 2011 [6 favorites]
Beautiful visualization of the candidate planets mapped to our solar system.
posted by gwint at 9:50 AM on February 8, 2011 [2 favorites]
posted by gwint at 9:50 AM on February 8, 2011 [2 favorites]
That's fantastic, gwint, thanks. I'm a little bummed by the relative scarcity so far of Earth-analogues, but it's very very early days.
posted by stavrosthewonderchicken at 5:54 PM on February 10, 2011
posted by stavrosthewonderchicken at 5:54 PM on February 10, 2011
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posted by Flunkie at 12:08 PM on February 3, 2011 [2 favorites]