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NASA Space Science

Kepler Discovers First Earth-Sized Exoplanets 179

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."
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Kepler Discovers First Earth-Sized Exoplanets

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  • Re:Zzzzzzz (Score:2, Interesting)

    by Anonymous Coward on Tuesday December 20, 2011 @03:10PM (#38438354)

    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 especially point D.
    In addition we can all revise our estimates of the Drake equation ( :-P

    Anonymous Astronomy Geek

  • apparent size (Score:5, Interesting)

    by polar red ( 215081 ) on Tuesday December 20, 2011 @03:29PM (#38438608)

    the apparent size of this planet is the same as an object of 0.5 mm on the moon.

  • The Real Question (Score:4, Interesting)

    by PortHaven ( 242123 ) on Tuesday December 20, 2011 @04:12PM (#38439128) Homepage

    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)

  • by mbone ( 558574 ) on Tuesday December 20, 2011 @04:19PM (#38439262)

    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.)

  • Re:Zzzzzzz (Score:5, Interesting)

    by lennier ( 44736 ) on Tuesday December 20, 2011 @04:39PM (#38439578) Homepage

    >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.)

  • by mcgrew ( 92797 ) * on Tuesday December 20, 2011 @05:05PM (#38439956) Homepage Journal

    Have you learnt nothing from all your years of watching Star Trek? The women are all blue or green, have 3 breasts, and want to KILL you!

    You know, I was ok with the transporter, and with warp drives going faster than light, but the idea that any outworld species would look anything like us whatever is ludicrous. And most movie and TV sci-fi does it.

    I fight bad sci-fi with more [] bad sci-fi. []

    Oh, and you're confusing Star Trek with Total Recall or HHTGT; I don't remember ever seeing the triple breasted whore of erotica in Star Trek, but she was a Martian in Total Recall, but a Martian decended from humans who had three tits because she was a mutant. Far more believable than a Human-Betazoid hybrid (the subject is covered in the two linked stories).

  • Re:Good news (Score:4, Interesting)

    by Maritz ( 1829006 ) on Tuesday December 20, 2011 @05:52PM (#38440666)
    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).
  • Re:Good news (Score:5, Interesting)

    by Grishnakh ( 216268 ) on Tuesday December 20, 2011 @06:49PM (#38441514)

    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).

  • Re:Good news (Score:4, Interesting)

    by Grishnakh ( 216268 ) on Tuesday December 20, 2011 @08:47PM (#38442870)

    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.

"Don't worry about people stealing your ideas. If your ideas are any good, you'll have to ram them down people's throats." -- Howard Aiken