Scientists pleasantly surprised by number of Earth-size, distant planets
The planet Kepler-10b orbits a star similar to our own Sun in its temperature, mass and size.
February 19th, 2011
06:02 PM ET

Scientists pleasantly surprised by number of Earth-size, distant planets

Where might extraterrestrials live? The first step is figuring out what other planets out there have conditions like our own.

Scientists using NASA's Kepler space telescope are working hard to find candidates for inhabitable planets. So far, it seems that for approximately every two stars in the galaxy, there is one possible planet, NASA's William Borucki said Saturday at the American Association for the Advancement of Science annual meeting in Washington.

Researchers have found some 1,200 candidate-planets and, of them, about 54 are earth-size candidate planets in habitable zones - in other words, perhaps at a distance from their stars that may be suitable for life. Earlier this month officials at NASA announced the discovery of five probable planets about the size of Earth, as well as six larger than our planet that are orbiting a single star. But bear in mind that Venus is also considered an "Earth-sized planet," and clearly no lifeforms live there (as far as we know).

Scientists on the Kepler mission revealed Saturday that you're probably going to have to wait until at least 2012 to find out anything substantial about the habitability of what appear to be Earth-sized planets. That's because scientists need to be able to see three transits of a planet around a star in three years before they'd be willing to say too much about them, and the project has only been going since 2009 (after all, our planet goes around the sun three times in three years).

And even then, Kepler wasn't designed to look at individual planets. But it might identify some that the James Webb Space Telescope, which will launch in 2014, can probe in further detail, looking at atmospheres and such. And note that the probability of having found our own particular planet using Kepler technology is only 12%.

And we won't be traveling to meet our potential new neighbors anytime soon. The stars about the size our sun that Kepler has been looking at are about 1,000 to 3,000 light years away, where one light year is about 6 trillion miles.

But there have been some fascinating surprises from the Kepler mission. One of them is that there appear to be a remarkable number of planets about the size of Neptune, which has a diameter four times that of Earth, said Sara Seager, physicist at Massachusetts Institute of Technology.

The planet Kepler-10b, shown in the photo above, is a particularly interesting find because it likely has no atmosphere, but does have liquid oceans that are essentially lava lakes, she said.

The existence of many small planets in the galaxy that Kepler has found also amazed scientists, because there was a possibility that they would have been destroyed by larger planets long ago.

"It was a wonderful surprise to see this large number of small planets we have found," Borucki said.

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Filed under: Science • Space
soundoff (325 Responses)
  1. jimzcarz

    With all of the strife in this world it really closes our minds to what really may be out there.
    We are so short sighted. Yeah...Go future hopefully we have something good to look forward to.
    Oh yeah....1st

    February 19, 2011 at 6:26 pm | Report abuse |
    • Diane

      What we really want to know is – What does Drake's Equation look like now?

      February 19, 2011 at 6:43 pm | Report abuse |
    • Ralf the Dog

      I think the first variable has been shown to be, "Many".

      February 19, 2011 at 6:48 pm | Report abuse |
    • Jojo

      does this mean that for every two stars there might be one possible Jesus?

      February 19, 2011 at 6:55 pm | Report abuse |
    • Stanislaw P. Radziszowski

      Drake's equation is a guess, so it doesn't matter how it changes.
      It is meaningless regardless of its evolution.

      February 19, 2011 at 6:57 pm | Report abuse |
    • Diane

      So are you Stanislaw! You're meaningless. Ha ha ha ha ha ha ha

      February 19, 2011 at 7:25 pm | Report abuse |
    • Staszek (short for Stanislaw)

      Hi Diane,
      I was merely pointing out that 5 out of 7 factors in the equation are
      disturbingly nonscientific. If a formula has just one such factor then
      it is meaningless. I am not a formula. How did you conclude that I am
      meaningless? I hope that you are wrong, both of us have meaning.

      February 19, 2011 at 8:23 pm | Report abuse |
    • derf

      true. isnt it also possible that there are life forms completely unlike those on earth on planets completely unlike earth? we know very little about the distant universe.

      February 19, 2011 at 8:27 pm | Report abuse |
    • Staszek (short for Stanislaw)

      In a 2003 lecture at Caltech, Michael Crichton, a science fiction author, stated:
      The problem, of course, is that none of the terms can be known, and most cannot even be estimated. The only way to work the equation is to fill in with guesses. [...] As a result, the Drake equation can have any value from "billions and billions" to zero. An expression that can mean anything means nothing. Speaking precisely, the Drake equation is literally meaningless...

      February 19, 2011 at 9:01 pm | Report abuse |
    • Dave

      Wow, Jojo...obsessive much? Everyone else here is talking about discovering new planets.

      February 19, 2011 at 9:09 pm | Report abuse |
    • John Not

      I wonder if extraterrestrials will have spell check, proof-readers and editors?

      February 19, 2011 at 9:22 pm | Report abuse |
    • Richard

      Well if Kennedy and Apollo hadn't killed Project Orion, we might well have already visited the closest star systems.

      February 19, 2011 at 9:55 pm | Report abuse |
    • LavaOceans

      "...a particularly interesting find because it likely has no atmosphere, but does have liquid oceans that are essentially lava lakes..."

      GOOD WORK NASA... Perfect habitat... NOT. Yank NASA's funding... We need the MONEY here on Earth... RIGHT NOW.

      February 19, 2011 at 10:11 pm | Report abuse |
    • Sunspot

      The Drake Equation ignores many factors that are relevant. Without our moon it is unlikely that our orbital inclination would be stable enough for long enough periods of time to allow intelligent life to flourish. And as pointed out, many of the factors that are included are outright guesses.
      It bodes ill for a well populated universe that we haven't detected any signals yet. And it's highly unlikely that a way will be found to travel faster than the speed of light, and at sub-light speeds we can't ever get very far. Some day we may discover life elsewhere, maybe even in our own solar system, but I doubt we'll ever meet any aliens we can chat with. It seems painfully obvious even now that higher forms of life are extremely rare, and probably don't last long. At the rate we're using up our natural resources we probably won't last much longer as a technological civilization capable of leaving the planet. If our species survives at all...

      February 19, 2011 at 10:18 pm | Report abuse |
    • realworld

      Wasn't this same story told on Feb. 3rd?

      February 19, 2011 at 10:30 pm | Report abuse |
    • BreakingNewsBlog - HPad3D - PortablePay - PhoPay - Sat3D.TV - FaceAnswers ...

      I'm not surprised ... it's what I believe from over 30 years just applying simple logic
      comments about the (already failed) """Google""" Lunar X Prize in this WIRED Science article:

      February 19, 2011 at 11:39 pm | Report abuse |
    • Steve

      I enjoyed Jojo's remark and thought it was a very relevant comment, albeit funny.

      March 18, 2011 at 9:32 am | Report abuse |
  2. jayman419


    February 19, 2011 at 6:32 pm | Report abuse |
    • LavaOceans

      No... Actually...airless and hot... rather yank Nasa's funding and redirect to reform broken court system...

      February 19, 2011 at 10:12 pm | Report abuse |
    • Cliff Vegas

      I wish we could move you and your other 'slash and burn' union busting boneheads live on Keppler 10b – leave you a KOCH idol to worship – so that the rest of us society-loving progressives can live without your mindless drivel.

      February 19, 2011 at 10:32 pm | Report abuse |
    • stwebb

      yeah...because we're right...and you're wrong! we've cornered the market on universal intelligence. our opinion means we know more than you! if we're the idiots, we don't know it because our brains are to insignificant to quantify thoughts such as those!

      February 20, 2011 at 1:29 am | Report abuse |
  3. Stanislaw P. Radziszowski

    This is not a photograph. It is a drawing by somebody guessing things.
    I am wondering why such an obvious error was not caught in the editorial process.

    February 19, 2011 at 6:34 pm | Report abuse |
    • StanTheMan

      CNN: "The planet Kepler-10b, shown in the photo above, [...]" They've really sunk to an all time low if they thought that was a "photo".

      February 19, 2011 at 6:42 pm | Report abuse |
    • StanTheMan

      Oh, forgot to mention... CNN doesn't have an editorial process. Every article has at least one significant error.

      February 19, 2011 at 6:43 pm | Report abuse |
    • Wzrd1

      CNN stopped using any editorial process OR fact checking. CNN ALSO does not hire any experts in silly nonsense like science.

      February 19, 2011 at 6:49 pm | Report abuse |
    • Ralf the Dog

      It is a photo of a drawing.

      February 19, 2011 at 6:49 pm | Report abuse |
    • StanTheMan

      It isn't a "photo of a drawing" either. It is a rendering.

      Before any geniuses ask why that sun isn't round, CNN couldn't figure out how to crop it to fit within their format, so they changed the proportions which squashed the entire image.

      February 19, 2011 at 6:52 pm | Report abuse |
    • Glenn

      What would you expect from a network that fired it's entire science and technology staff. Miles O'Brien probably laughs out loud every time they post something like this.

      February 19, 2011 at 6:56 pm | Report abuse |
    • Josh

      Someone always has to nitpick.

      February 19, 2011 at 6:57 pm | Report abuse |
    • Won 3rd grade spellimg bee...

      This 'photo' started life as a square, so resize width to match the height and it looks much better.

      February 19, 2011 at 7:28 pm | Report abuse |
    • Bensky

      Who cares? It illustrates the concepts laid out in the article very well. Go back to sleep.

      February 19, 2011 at 7:28 pm | Report abuse |
    • Dave

      This is CNN, not Fox. Anyone thinking that is a photo is not likely literate enough to even use the internet. I mean, some people think movies of aol roman legions are actually the REAL roman legions.

      February 19, 2011 at 7:45 pm | Report abuse |
    • chuckmartel

      CNN should be embarassed for itself. They need serious remedial education.

      February 19, 2011 at 7:49 pm | Report abuse |
    • Chris

      Guys you really need to stop complaining about the photo, isn't it obvious that you altered the photo by observing it.........

      February 19, 2011 at 9:57 pm | Report abuse |
    • Chris

      Why was the error not caught? This is the web. The web is the bottom of the media food chain I wonder if the author even knows that Kepler can't actually photograph planets.

      February 19, 2011 at 10:42 pm | Report abuse |
    • ZweiStein

      Are you sure? We paid for a photo.

      February 20, 2011 at 7:14 am | Report abuse |
  4. BooSure

    I think its great. Finding all these new planets. I for one miss being a kid and all the wonders of the world as a kid. It gives me something to wonder about as an adult.

    February 19, 2011 at 6:35 pm | Report abuse |
  5. mywinejourneys

    I've always thought that we would find earth-sized planets (and not just the extrasolar supergiants) when we finally made telescopes capable of detecting them. Given the magnitude of the universe, probability is in favor of the existence of other intelligent life in the universe.

    February 19, 2011 at 6:35 pm | Report abuse |
    • Chris

      The one example we have, Humans, shows us that technological civilizations must be very rate. and the microbes must be very common. One cell microbes just as soon as the Earth cooled enough for them to live. Humans lived for a million plus years with zero change, just sharp rocks tied to sticks for hundreds of centuries. We'd still be there but for some (I'm sure) freak thing where something "clicked" 10,000 years ago. Why were there no smart dinosaurs, what if they did not die out in that comet impact. I suspect civilizations are rare, maybe even unique. But live maybe common.

      February 19, 2011 at 10:57 pm | Report abuse |
  6. JOnh

    I'm be the first to say it and blame religion for our slow progress.

    February 19, 2011 at 6:35 pm | Report abuse |
    • BooSure

      Blah. Boring and overused comment.

      February 19, 2011 at 6:36 pm | Report abuse |
    • Alex

      I agree with your statement. There is a lot of reasons that we know so little but this is a big one imo...

      February 19, 2011 at 7:42 pm | Report abuse |
    • roflamericanwinner

      Um isn't the telescope used by the vatican one of the largest and most advanced? LAWL you fail. I think God want's us to focus on the bigger picture, but is demonstrating we need to get our act together with eachother first.

      February 19, 2011 at 8:09 pm | Report abuse |
    • Nathan

      The Vatican placed Galileo under house arrest and banned his book that said the Earth revolved around the Sun. I don't think having a large telescope quite makes up for all of the harm they've done to scientific progress.

      February 19, 2011 at 8:26 pm | Report abuse |
    • philtration

      Religion keeps us tied to the dark ages and holds us back as a nation and as a species.

      February 19, 2011 at 9:15 pm | Report abuse |
    • Justina

      Religion says present mankind is too sinful to have another planet because ruining this one was bad enough. How true! Be realistic and give up, you evil Earthlings.

      February 20, 2011 at 1:32 am | Report abuse |
  7. ang

    I've imagined myself traveling all around space already.Thanks for giving me that thought.

    February 19, 2011 at 6:37 pm | Report abuse |
  8. matt

    Why aren't we fabricating a ship that runs on nuclear, with 20-30 heary, adventureous souls on a one way trip into deep space? They would be self-sufficient, we would keep in contact, they could do experiments along the way etc, etc. It seems to me that this is the next loical step for mankind

    February 19, 2011 at 6:38 pm | Report abuse |
    • Wzrd1

      Because, we lack the ability to build a self-sufficient, self-contained, environment. OR engines that could reach another star within 7 lifetimes. Or even engines that could reach another star.

      February 19, 2011 at 6:50 pm | Report abuse |

      i am already.. but i need help... come over and help.. bring some duct tape and batteries

      February 19, 2011 at 7:04 pm | Report abuse |
    • Andrew

      Because on that distance scale, any ship we send out now will likely be so slow that some two hundred years into the trip those 20-30 adventurous souls will find themselves overtaken by a much better design. Once we can get some really efficient particularly long term (decades) ion thrusters so that there's continuous long-term sustainable thrust, we can consider going out into the cosmos. Eventually, running those things long enough, it should be possible to make it somewhere out in space. You might however have substantial problems slowing that craft down relative to anything else.

      February 19, 2011 at 7:05 pm | Report abuse |
    • qiox

      The fastest ship we can make (using nuclear power would change nothing) would take 50,000 years to reach the closest star. Enjoy the trip.

      February 19, 2011 at 7:10 pm | Report abuse |
    • winter059

      The Tea Party won't let us anyway.

      February 19, 2011 at 7:48 pm | Report abuse |
    • Geoff

      It's quite simple. First of all, you would need food. And lots of oxygen. And toilets. Basically, the biggest problem would be designing a toilet that can flush 500,000,000 times without malfunctioning. Also, you'll die along the way too, so you'll probably be the first corpse to be ejected into space, where you will either freeze or vaporize instantly. Even if we solved the food/toilet/clothes/etc. problem, you would still have problems communicating. Radio waves take time to travel, so if you travelled 500 lightyears, it would take 500 years for your message to reach Earth, and another 500 for "Earthlings" to reply. Basically, you need a self-contained planet that travels at an impossibly fast speed. Maybe you'll get lucky and get blown up by intelligent alien space pirates before you die of hunger.

      February 19, 2011 at 10:05 pm | Report abuse |
    • Grafikman

      Actually the biggest problem would be keeping the crew from going insane. Stuck in a tin can for the rest of your life? Special kinds of hallucinogenics and antidepressants would have to be developed to prevent the crew from throwing themselves out the airlocks.

      The traditional route is just unfeasible, I agree. But I'm still hoping for some kind of wormhole/extradimensional/warp drive solution. Remember, just over 100 years ago human powered flight was still laughed at, 60 years ago the moon landing, 20 years ago extrasolar planets. Quantum physics already describes the possibility of traversing a sublayer of our own dimension to bypass physical distances, and I wouldn't be surpised a bit if some corporate or military thinktank had already made some strides to that end...

      February 20, 2011 at 1:09 am | Report abuse |
  9. banasy

    I am mildly ecstatic that the scientists are pleasantly surprised. A big subdued whopee was heard.

    February 19, 2011 at 6:38 pm | Report abuse |
    • SB

      Does it make you feel cool to pretend that science, exploration and discovery aren't important?

      February 19, 2011 at 6:41 pm | Report abuse |
    • winter059

      Well I thought the comment was funny.

      February 19, 2011 at 7:56 pm | Report abuse |
  10. mclj2011

    The scale of the universe is so vast, that it makes sense that we'd find other plants like our own. Whether they are habitable or not, is a matter for future scientists to determine.

    February 19, 2011 at 6:39 pm | Report abuse |
    • SB

      Not too far in the future. The generation of telescopes that can answer that question for many of these planets is already being built.

      February 19, 2011 at 6:48 pm | Report abuse |
    • Ralf the Dog

      One of these days, a future JPL telescope will point at a far star and see a giant telescope pointed back at it.

      February 19, 2011 at 6:52 pm | Report abuse |
  11. SB

    Couple of things to note.

    "So far, it seems that for approximately every two stars in the galaxy, there is one possible planet,"

    There are at least 200,000,000,000 stars in our galaxy. More recent measurements suggest the number may be twice that. That suggests a truly staggering number of planets await discovery. And keep in mind there are about 100,000,000,000 other galaxies that we can see from here, so far.

    Second thing is that the general public is now able to comb through the Kepler data without a PhD, courtesy of You can search for planets, binary star systems, and other goodies by examining the light curves with a very friendly and straightforward interface.

    And finally, just because we can't go to these planets doesn't mean we can't study them and learn from them.

    February 19, 2011 at 6:40 pm | Report abuse |
    • StanTheMan

      Strange how the article says of the 1200, we've found either 54 or 5. Neither is a 2-for-1 special.

      ... and since there are at least 200,000,000,000, you'd think they would have found 100,000,000,000 by now if you believe the unsubstantiated 2-for-1 claim CNN is reporting.

      February 19, 2011 at 6:47 pm | Report abuse |
    • SB

      Stan, that's not at all accurate. 54 is the number of planets that were found in the habitable zones of stars, in the last batch of processed data from the spacecraft. So far. The total number of planet candidates found by the spacecraft so far numbers in the hundreds. The spacecraft is examining a field of ~200,000 stars. And as it states in the article, to see a planet in an Earth-like orbit around a star like our own, once, takes one year.

      The numbers are not unsubstantiated, and they do not come from CNN. The "2 for 1" deal is how the data is shaping up so far.

      February 19, 2011 at 6:51 pm | Report abuse |
    • Mark

      @StanTheMan – newsflash, you're not funny. And when you try to be smart by picking apart the article, you only demonstrate that you seem unable to read and comprehend what was written. The math makes total sense, IF you bother to read it properly. Thanks for playing. Quit while you're ahead...each additional comment you post makes you look even more foolish.

      February 19, 2011 at 7:00 pm | Report abuse |
    • StanTheMan

      You know more about this than the author and especially me. But my point was the numbers don't make sense. Even if they can analyze one per year, then so far they should be at one since it launched less than two years ago. It seems a bit premature to claim 2-for-1 when, like you said, there are 200,000,000,000+ stars out there. Even 5, 54, or 1200 might be the result of some 2-for-1 analysis, but doesn't the sample size seem a bit small?

      February 19, 2011 at 7:04 pm | Report abuse |
    • StanTheMan

      @SB – My previous comment was for you. Thanks for clarifying.

      @Mark – newsflash: I wasn't trying to be funny. I was having trouble comprehending the article. That's why I responded to SB asking for clarification because he understood. Feel free to continue being nonconstructive since that seems to be all you have to offer.

      February 19, 2011 at 7:11 pm | Report abuse |
    • SB

      Stan, the spacecraft samples the brightness of those 200,000 stars every 30 seconds. Not one at a time, but all at the same time.

      It then takes quite a while to assemble the data into a form that can be combed through. Even though the spacecraft was launched in 2009, the amount of processed data hasn't yet caught up. They're still only on the first few months' worth... and that should tell you something, when you consider how frequently planets are already being found.

      Even after detecting a candidate transit (the dip in light as the planet comes around... basically an eclipse seen from very far away) you still need to take followup measurements with other means to confirm whether it's a planet or not. Gravity, and therefore orbits, are predictable, but it still takes time to make an orbit.

      February 19, 2011 at 7:11 pm | Report abuse |
    • Mark

      @StanTheMan – apparently you forgot about your "level 3 diagnostics on the EPS conduits" remark. You're having trouble understanding the article because you don't want to. You're intent on trying to pick it apart (including your "photo vs artist's drawing" comment). Sure, it's a minor error that got through. Anyone with reasonable common sense and a bit of education will know that's not an actual photo. Does it make you feel better about yourself to point it out? If so, then I'm glad for you.

      February 19, 2011 at 7:20 pm | Report abuse |
    • SB

      Ok you two, don't make me pull this article over or NO ONE will get planets.

      February 19, 2011 at 7:24 pm | Report abuse |
    • Rich


      Think of this article as a "Reader's Digest" that summarizes the Kepler results. The "2-for-1" claim is the result of statistical analysis provided to the author from a member of the Kepler team. The author of this article wouldn't understand and wouldn't want to present the statistical analysis to you anyway.

      Long story short, in order for the Kepler satellite to detect a planet orbiting another star, the plane of the exoplanet's orbit must line up exactly edge on with us the observer. When the planet passes in front of the star, it dims the light we see from the star. If we detect something like this, we consider it a planet candidate (assuming it has passed numerous false-positive tests).

      The probability of an exoplanet's orbit lining up just right with an observer here in our Solar System can be determined. Thus, if you find a certain number of planets that have the plane of its orbit aligned with an observer here, you can extrapolate that number to account for the number of systems that DO NOT lie edge on. For example, if 1 out of a 100 extrasolar systems has an orbit aligned with an observer, and you detect 10 such systems, this suggests that there are 990 other extrasolar systems present that can't be detected by Kepler (because those exoplanets won't eclipse the host star).

      There are many other factors that are considered, but this is kind of it in a nutshell, lol. And 200,000 stars is an incredible sample size for astronomy. I wish we could all be so lucky 😀

      February 19, 2011 at 8:49 pm | Report abuse |
    • Kyle_Bc

      it seems reasonable to me to assume that when they say 'star' they actually mean 'sun', which IS a star. this makes the 54 number make more sense.

      February 19, 2011 at 9:10 pm | Report abuse |
    • StanTheMan

      @Mark – "apparently you forgot about your "level 3 diagnostics on the EPS conduits" remark. You're having trouble understanding the article because you don't want to."

      My "level 3 diagnostics on the EPS conduits" trek joke to RUFFNUT was in reply to his trek joke. He followed up with another joke since then that you might have missed. You're having trouble understanding the joke because you don't get it.

      I was going to write more but I realized it was a waste of time. You misinterpret or misunderstand what little I've said here and then project your own "pick it apart" and "choosing to not understand" traits on me. If it helps, I will concede that you won your Big Internet Fight. I will graciously bow out and get back to more important things. I do wish you well.

      @Everyone – If I offended anybody, I sincerely apologize.

      @RUFFNUT, I hope we shared a chuckle.

      @Everyone Else – thanks for being helpful.

      February 22, 2011 at 11:22 pm | Report abuse |

    i going out back and going to start building a di-litium reactor core.. i have some lithium batteries ran in series and once i get the shields built around the reactor core i should be able to power my fussion drive..

    i bought some scuba gear and got new window seals on my camaro and should be able to blast of tomarrow night once the bateries are charged up..

    i also bought the blue prints for a computer chip from the last navigator.. it should enable my camaro to escape earths gravity and keep me safe..

    February 19, 2011 at 6:46 pm | Report abuse |
    • StanTheMan

      Don't forget to run Level 3 Diagnostics on the EPS Conduits.

      February 19, 2011 at 6:50 pm | Report abuse |

      i dont have to cause i double duct taped them with black duct tape and then put a shop vac on them to test for leaks... there good belive me..

      i also ran 10ga wire from the battery to the reactor so the power converters should be ok.. i also am taking some extra ni-cads with me just incase..

      February 19, 2011 at 6:58 pm | Report abuse |
    • PlutoTheDog

      RuffNutt, that is the funniest thing thing I've read on the internet in many moons. thank you

      February 19, 2011 at 9:01 pm | Report abuse |
  13. Sach

    I guarantee you extraterrestrial life is here or has been visiting here for some time. The ones that know this know that people just couldn't handle not being the only game in town. Religion would be void if this came out and it would be a giant leap for mankind if Wikileaks comes out with something.

    February 19, 2011 at 6:51 pm | Report abuse |
    • Ralf the Dog

      No extraterrestrial life has ever made contact with the Earth. Why would we?

      February 19, 2011 at 6:55 pm | Report abuse |

      what ever... star trek is really real.. you just stuck in a holo-deck and don't reallize it..

      February 19, 2011 at 6:59 pm | Report abuse |
    • standingwave

      Never understood this assumption that we couldn't handle it."Aliens have made contact!Quick lets run screaming into the streets then commit suicide."

      February 19, 2011 at 9:07 pm | Report abuse |
    • Sunspot

      As Stephen Hawking has pointed out, if this planet had been discovered by intelligent life in the past it is very likely they would have mined out all of the valuable natural resources immediately.

      February 19, 2011 at 11:20 pm | Report abuse |
    • Grafikman

      As much as I revere the ground Stephen Hawking rolls on, I think he totally missed the mark on that one. Why would an intelligent species bother with mining our dinky little planet, when there's an unimaginably vast fortune in precious metals and ores ripe for the picking in our own asteroid belt? Not to mention the rest of the galaxy. It would be like fishing in a pond hoping to catch marlin with the ocean just over the hill...

      February 20, 2011 at 12:52 am | Report abuse |
  14. Don

    Three earth years are not the same length as three venus years so why would we have to wait "three years" to watch the rotation of these planets when they clearly have different lengths to their rotations since they don't have the same distant from their sun as earth does to our sun. The logic these scientists use baffles me sometimes.

    February 19, 2011 at 6:52 pm | Report abuse |
    • SB

      Replace "year" with "orbit" and be baffled no more.

      February 19, 2011 at 6:54 pm | Report abuse |
    • Mark

      Along with SB's comment, 3 years is also an approximation. If the planet is to possibly be habitable (at least under the conditions we believe to allow habitability) then the star it orbits will be similar in size & temp to our own Sun, and the distance the planet orbits from its star will also be similar to the distance between Earth and the Sun. Therefore, assuming it orbits its star at the same speed as Earth, its "year" will also be similar to our year.

      ps. "Rotation" is the time it takes a planet to spin on its axis (ie. 1 day). "Revolution" or orbit is the time it takes a planet to make 1 trip around its star (ie. 1 year).

      February 19, 2011 at 7:10 pm | Report abuse |
    • qiox

      They are talking about stars in the habiltable zone. Venus is not in that zone, it's too close, hence has a shorter year. The one's in the zone are, roughly, the same distance from their star as the earth is from the sun. Hence, they have roughly the same length of year.

      February 19, 2011 at 7:13 pm | Report abuse |
    • Death Panel Sarah

      Also, three years would put the planet at the maximum possible distance to be habitable. (i.e. Mar's orbit)If it takes longer than three years, it would be too cold for life to exist.

      February 19, 2011 at 8:23 pm | Report abuse |
    • Geoff

      @Death Panel Sarah, that may be true for Mars, but since Mars has a much smaller mass than Earth, it lacks an atmosphere. If it had an atmosphere, it would be able to retain heat, and perhaps it would be possible for life to exist on Mars. Therefore, a larger-than-Earth planet slightly outside of the 'habitable zone" might still be able to support life.

      February 19, 2011 at 10:14 pm | Report abuse |
  15. banasy

    This is a really interesting's informative and I'm learning from all the comments...but the headline still cracks me up. I don't know why, it just does.

    February 19, 2011 at 7:04 pm | Report abuse |
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