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Kepler Discovers First Earth-Sized Exoplanets
ananyo writes "NASA's Kepler telescope has reached one of its major mission milestones: finding an Earth-sized planet outside the Solar System. What's more, it has done it twice in the same star system. Whizzing around the star Kepler-20, about 290 parsecs (946 light-years) from Earth, is not only an Earth-sized planet, but also something just a touch smaller — a Venus."
Congratulation to NASA. I hope there is a plan for Kepler 2.0!
"but also something just a touch smaller — a Venus." If there's a Venus and no known Mars... then does that mean it's all women? Sign me up!
Comme on, another planet, it has been a week since the last one, will my extensions work on this one?
Um, what? What exactly do you think Johannes Kepler was, a washing machine?
Learning HOW to think is more important than learning WHAT to think.
Apparently the number 20 was assigned earlier, when the larger outer planets were discovered in this system.
Yes, that is a bummer, but consider the other things we have learned, primary among them the fact that solar systems do not always form like ours with the rocky planets closer to the sun. This has major implications for theories of solar system formation, see http://www.astronomy.org/astronomy-survival/solform.html especially point D. :-P
In addition we can all revise our estimates of the Drake equation (http://en.wikipedia.org/wiki/Drake_equation)
Anonymous Astronomy Geek
Damn that's fast!
Ascalante: Your bride is over 3,000 years old.
Kull: She told me she was 19!
Ummm ... as much as Kepler is the name of the device, Johannes Kepler laid out the mathematics of orbits. You know, Kepler's Laws.
Naming stars Kepler-20 (or whatever) is naming them after important scientists ... and since it's looking for things which orbit, it's quite apt.
Lost at C:>. Found at C.
It could still have habitable temperatures if it was a tidally locked planet. The chances of that occuring increase as a planet approach it's star. Any life on such planets would certainly be interesting.
You want to revise everything based on 2 data points? Out of billions/trillions/way-too-many-for-2-points-to-matter?
Yikes.
There are two types of people in the world: Those who crave closure
The Kepler telescope only has a relatively narrow field of view compared with the entire sky. So most near by planets will not be called Kepler-nc.
Zzzzzzz??? Really??
Twenty five years ago, finding an exoplanet was considered to be some forward looking science that might not ever happen, and the belief then was that planets were likely quite rare. Ten years ago we'd found some planets, but they were all gas giants.
Now, we find a planet which is close to Earth in size, in a solar system with 5 planets in it, 1000 light years away That's some heavy stuff.
If you're incapable of understanding that this is actually pretty significant, maybe you should go back to your coloring books ... the estimate of the number of planets there are likely to be in our galaxy alone has likely gone up by several orders of magnitude in the last 20 years or so.
We're quickly changing from "oh there's likely not many planets" to "the universe is full of them" ... it's hard not to think that even if it's not what we'd call intelligent life, there's likely more than a few places that have evolved some form of life.
The more we see stuff like this, the more we see just how vast and astounding the universe around us actually is.
Lost at C:>. Found at C.
the apparent size of this planet is the same as an object of 0.5 mm on the moon.
Yes, I'm left. You have a problem with that?
When you have a sample set of 1; then adding 2 data points is a fantastic expansion in scope even if we are quite positive that we do not have all of the potential information (soon to be discovered). At this early stage, finding a handful of other planetary systems has effectively multiplied what we know about planetary systems a thousandfold or more, even if we consider ourselves to be mostly blind still.
- Toast
The telescope is "seeing" the planet as it was 946 years ago ... maybe it's not even there any longer
I know, planets these days are always picking up and vanishing without even saying good bye. First Ceres, then Pluto. Every morning I wake up I breathe a sigh of relief that the Earth is still here.
The telescope is "seeing" the planet as it was 946 years ago ... maybe it's not even there any longer
946 years on a cosmic scale is no more than a blink of an eye. The likelihood that any visible planet has merely vanished in that short a time is incredibly remote. Worrying about it would be like freaking out every morning before you go to work because the building just might have burned down overnight.
"People who think they know everything are very annoying to those of us who do."-Mark Twain
We're quickly changing from "oh there's likely not many planets" to "the universe is full of them"
I wouldn't quite say that.
I don't really think that the estimates of how many planets there may be has increased. Instead, our technology has increased so that we can actually start finding the planets that we've always assumed were there.
The somewhat-dubious values that Drake used in 1961, according to Wikipedia, include:
fp = 0.5 (half of all stars formed will have planets)
ne = 2 (stars with planets will have 2 planets capable of developing life)
The value given for ne seems to be rather optimistic, but it's still too early to have reliable numbers. It will be a long time before we can take any arbitrary star, and see exactly how many planets it has.
Free unix account: freeshell.org
Is not will we discover an earth gravity (size is meaningless, it's the gravity that's an issue) planet at earth temperature from it's sun, but when.
And more importantly, when will we find one with 25 light years from Sol.
NASA's primary focus right now IMHO should be giving out X-prizes for corporate achievement in space flight and endeavoring to devise means for reaching stars:
- how to get a probe up to near light speed.
- how to maintain communication with said probe (most likely via entangled diamonds)
- get us off this rock (within 150 years)
Kepler detects transits - i.e., only planets that happen to pass in front of their stars as seen from Earth. That is going to be pretty rate. If you had two Keplers, you (or at least I) would point it at another patch of sky, to get more samples.
Here is a way to think about the math - the radius of the Sun is about 1/200th the radius of the Earth's orbit, so for some random observer in the galaxy (or for us, trying to find something like Earth), there is only about a 1 in 40,000 chance that transits will occur and, of course, for Earth they will happen once per year, so it's going to take 3 or 4 years to really confirm it (and get a good handle on the orbit). Kepler is looking at 145,000 stars with a nominal mission length of 3.5 years, so it has a decent chance of detecting one or a few Earth-like planets in Earth-like orbits, if almost every stellar system has such a planet. (That choice of mission parameters is, of course, no accident.)
Now, for these new Kepler-20 guys, the orbital period of the Earth-sized planet is 20 days, so you only have to wait maybe 60-80 days to confirm it, and the orbital radius is much smaller, so the probability of transit is much higher. (If the orbital radius is 10 stellar radii, this probability is about 1%, or hundreds of time larger than for a true Earth analogue).
So, putting all of that together, you would expect Kepler to spot hundreds of hot Earth's for every Earth analogue it seems (assuming both are more or less equally common out there) and that is, more or less, what is happening. (Of course, we won't know about the objects in Earth type orbits for a few years yet.)
Yes. These are transit measurements. They see the drop in light of the star, or not. If they see it, they can estimate how much the intensity changes, which gives them the ratio of the area of the star and the area of the planet. They can also time the duration of the transit, which, together with the period between transits and some information about the star, gives them the star's radius, and thus the planet's radius. If you can detect the transit at all, you should be able to get all of these things.
>We're quickly changing from "oh there's likely not many planets" to "the universe is full of them" ... it's hard not to think that even if it's not what we'd call intelligent life, there's likely more than a few places that have evolved some form of life.
The more we see stuff like this, the more we see just how vast and astounding the universe around us actually is.
And yet, if General Relativity is correct, there's still no conceivable way for a planet 1,000 lightyears distant to have any kind of communication with us, or us with them, without a two-millennia time lag. And that's just for extremely high-power/sensitivity radio signals, let alone any kind of matter-based probe. I for one find that picture of the cosmos incredibly depressing: there's potential neighbours all around, but no possible way to communicate until our civilisation crumbles.
That's really why I hope that General Relativity is not, in fact, correct in its pessimistic assumptions about lightspeed being the final arbiter of causality and that there's some kind of cosmic loophole which would allow interstellar trade and travel for beings with humanlike lifespans.
Otherwise, no matter how many exoplanets or other wonders we find in deep space, the sensible logical implication is that we should ignore them because they could never have any causal impact on our civilisation. (Other than downloading some alien DNA from radio signals and using it to breed an alien-human hybrid Hot Chick, which science fiction tells us is always an excellent idea with no possible complications.)
You are not a brain: http://books.google.com/books?id=2oV61CeDx-YC
What? It doesn't matter if we can have a direct conversation with alien life forms. The important discovery would be the simple fact that they exist. As of this moment our own planet is the only one in the whole of the universe that we know life exists on. Just finding a second one would be one of the great discoveries in our species' history. It's a bit silly on your part to suggest that such a discovery wouldn't in fact have a significant effect on our civilization.
I'm a loner Dottie, a Rebel.
Depends on the eccentricity of the orbits. Pluto, for example, would be almost impossible to detect since its orbit almost never crosses the plane of the orbit of the rest of the planets. (Just ignore the time scale for now.) If another star had passed very close while the planets were forming it could have induced a serious warp to the circumstellar disk and orbits could be all over the place. For that matter, I think Uranus's orbit is sufficient inclined from the ecliptic that it would probably be missed as well.
"Think about how stupid the average person is. Now, realise that half of them are dumber than that." - George Carlin
The problem with this thinking is the presumption there is only two data points. There are currently at least 19 different planetary systems with at least three or more planets which can be used for a comparison, and almost everybody involved with extrasolar planets knows this is just the beginning of discoveries. All told, there have been over 700 different planets which have been confirmed outside of our little old Solar System.
I would say that is enough to begin some statistical models and try to come up with some general trends based upon real data besides the single data point of the Sun and its planets. More significantly, this seems to indicate that planetary systems around stars are quite common to the point that stars without planets seem to be an exception... particularly if those stars are solitary stars rather than in systems of multiple stars.
Admittedly we are still mostly blind about what is "out there", but the Kepler survey seems to be providing some real statistical information about how common planetary systems might be, and since so many of the Kepler telescope candidates seem to be found in groups of multiple planets, it seems very likely that one common presumption of planetary formation being in a disc-like structure seems to be holding out very well. What the Kepler survey is really good at doing is identifying candidates which can then be studied with better telescopes now that we know some properties of these particular planetary systems, or even that they exist at all.
Um, what? What exactly do you think Johannes Kepler was, a washing machine?
I don't know, I've never keppled!
You are not a brain: http://books.google.com/books?id=2oV61CeDx-YC
You and I are in agreement. The poster I was replying to was indicating that we should not modify our theories until we get more data, I was countering that we definitely SHOULD be modifying our theories as we go, since we now have more than just the data on our own system. And when starting with just our own system, the next couple of systems discovered increases our available data by a phenomenal amount. Let the updating begin!
- Toast
Claudio Maccone's proposal to use the Sun as a giant gravitational lens (FOCAL) is pretty astounding. All you gotta do is send your satellite out to about 550 AU (easy peasy eh?) - I think I recall reading that if you were to train it on a planet in the Alpha Centauri system you'd be able to resolve cars in the street assuming there are cars and streets there (bound to be). Not easy to steer though, you'd need to know well in advance what you were aiming it at. One nice thing is that the focal length goes to infinity, so even if you're shooting further out (say 1000AU +) you're still able to get a great picture.
I do not want your cheap brainburning drugs. They are useless for work. And I am a working man today.
Unfortunately, the only way to get that size and earthlike surface gravity is to have such a low density that there's no solid surface. Saturn is already less dense than water and it still has too much surface gravity. We need rocky planets, and for a rocky planet to have earthlike gravity it's going to have to have a roughly earthlike size.
So the obvious thing to do is not to look at some boring distant planet, but look at some star a few thousand light years away. But don't look directly at it, use it as a second gravitational lens to look at *another* star, and indefinitely extend the range of the telescope. Assuming the focal point isn't directly on the opposite side of the gravity well it would be possible to aim the telescope within a small angle and conceivably bend the light path around until it was focusing back on our own planet Earth's past. Our photons stream ever outward but presumably some of them do return by circuitous routes for us to collect and image our own history.