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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."
"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!
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.
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.
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
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.
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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.
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.
Sadly the closest thing to this would have been the Terrestrial Planet Finder which was a superbly ambitious programme and it's a real shame that it's finally been cancelled after having been mothballed for what seems like ages now. Hopefully Kepler's results with either get the programme going again or provide impetus for a similarly ambitious programme. Ideally we should have a technology that can bring spectrometry to bear on a distant world and give us the chemical composition of its atmosphere. If for example free oxygen were detected that would be incredibly compelling evidence for life as you wouldn't expect to find free oxygen without a process that continually creates it (like photosynthesis).
I do not want your cheap brainburning drugs. They are useless for work. And I am a working man today.
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.
What's most pathetic isn't that the US is totally dropping the ball on this stuff, it's that other nations that have the ability to take over this important work aren't bothering to do so. Why aren't the Europeans doing more space exploration? They have 50% more population than we do, many of their economies are stronger (just look at Germany's economy), so what's the problem? All they can manage is one little probe to the outer planets?
Everyone whines about how America is going down the toilet (which it is), but I don't see anyone else stepping up to fill in, except China (which is much farther behind technologically, so has more ground to cover to catch up).
Ok, you've named a few more projects, but then you admitted their budget is a paltry 1/3 of NASA's. Why is that? The EU has 1.5 times the USA's population, and economies that are in better shape, Greece notwithstanding. On top of all that, the EU doesn't waste nearly as much money on its military as the US does, and taxes are generally higher. What's the problem? The EU should be easily leading the world in space exploration given all this.