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Space Science

Can We Travel To That Exciting New Exoplanet? 662

An anonymous reader writes "The news last week that exoplanet Gliese 581g may be in the 'Goldilocks zone' and could therefore hold liquid water and alien life got everyone all excited, with good reason. A potentially habitable planet — and only 20 light years away! But to put things in perspective, here are a couple of estimates on what it would take to travel to Gliese 581g. One scientist puts the travel time at 180,000 years based on current space flight technology, while another explains that it could be quite quick if we build a matter-antimatter drive, and can figure out how to bring along 530 times as much mass in fuel as is contained in the ship and cargo itself."
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Can We Travel To That Exciting New Exoplanet?

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  • Reality check (Score:5, Insightful)

    by elrous0 ( 869638 ) * on Tuesday October 05, 2010 @02:16PM (#33797156)

    Dave Goldberg, coauthor of A User's Guide to the Universe, took a more optimistic approach. In a blog post, he assumed an average travel speed of 92 percent of the speed of light

    That is one HELL of an assumption. Considering that the fastest space vehicles [] ever created took 3 months to travel a mere 8 light *minutes* (somewhere around one-16000th the speed of light), the assumption that we will ever reach even a significant fraction of the speed of light with a vehicle created anytime in the conceivable future is a bit of an overstretch to say the *least*. At the speed of the Helios probes, that journey to this planet would take over 300,000 years, BTW. So even McConville's 180,000 year estimate is a bit optimistic.

    And that's not even throwing in the navigation difficulties (that's going to require some epically precise calculations), the damage such a long trip would inflict to the craft with radiation and micrometeorites, the need for braking when you get there, etc.

    Interstellar space is a big VAST empty that few people appreciate. When I was a kid, all the science fiction and popular misinformation made it sound like the next solar system started right at the edge of our own. It was only when I got older that I realized that our solar system is just a tiny dot in a huge sea of lonely empty. The scale of distances between solar systems is difficult for the human mind to even appreciate.

  • Re:Reality check (Score:3, Insightful)

    by Anonymous Coward on Tuesday October 05, 2010 @02:20PM (#33797222)

    It was supposed to be an optimistic estimate:

    That is very bad news. Let’s put things in perspective and imagine sending the international space station (m= 370 metric tons) to Gliese 581g. The whole trip would require something like:

            * E = 1.8 x 10^25 Joules

    Or approximately 5% of the sun’s energy output in a second. That sounds reasonable, until you realize that that tiny amount would take approximately:

            * 3 million years to collect on earth if the entire surface were covered with solar panels

    That, as the physicists say, is non-trivial.

    Better start building that Dyson sphere.

  • by Braintrust ( 449843 ) on Tuesday October 05, 2010 @02:28PM (#33797356)

    Technological limitations aside, this is the first time in several hundred years that we have had a further shore to sail to... a place where no man has gone before, as the saying goes.

    That has to count for something.

    For me this is the most profound discovery in the history of us. Without hyperbole. The only thing I can see superseding it is, of course, the confirmation of life itself out there.

    I think we need a further shore... and I'm glad I lived to see a new one.

  • by dreamchaser ( 49529 ) on Tuesday October 05, 2010 @02:30PM (#33797384) Homepage Journal

    You are correct, but just a mere few hundred years ago the fastest we could move was a dozen or so miles in a day. I am optimistic that if we don't manage to destroy ourselves we'll find means of providing energy and types of propulsion that would seem like magic to us today (kudos to A.C. Clarke for the reference).

  • by jandrese ( 485 ) <> on Tuesday October 05, 2010 @02:36PM (#33797496) Homepage Journal
    I don't think you understand the magnitude of the problem. These are fundamental physical limits of mass and energy we're talking about. Literally the only chance we have of getting to another solar system is to discover an entirely new branch of physics that somehow makes interstellar travel feasible. Probably the best bet is to copy it from visiting aliens, if any ever bother to visit.
  • Re:Reality check (Score:1, Insightful)

    by Anonymous Coward on Tuesday October 05, 2010 @02:37PM (#33797514)

    Hey, if we figure out how to dramatically increase human life expectancy, she still might be right.

    We'll certainly get that before we get interstellar travel, at any rate.

  • by jandrese ( 485 ) <> on Tuesday October 05, 2010 @02:40PM (#33797556) Homepage Journal
    Nanomachines can only do all of that stuff because you haven't thought through the problems yet and realized the limitations. How you power a machine that small, or make it intelligent, or give it sensors, or pretty much anything is still a lingering question. Once you get past the sci-fi aspects, nanomachines start to look depressingly limited. Self replicating nanomachines are especially nutty, given how complex such a device would need to be.
  • Re:Reality check (Score:4, Insightful)

    by frostfreek ( 647009 ) on Tuesday October 05, 2010 @02:41PM (#33797594)
    I think you missed a digit there; more like 16000 times.
  • by boarder8925 ( 714555 ) <thegreentrilby&gmail,com> on Tuesday October 05, 2010 @02:49PM (#33797740) Homepage

    Would it not make sense to communicate first?

    Provided that if there is life out there, and if it's intelligent, said life can understand any of our languages, or would care to take the time to figure out what it meant.

  • by PinkyGigglebrain ( 730753 ) on Tuesday October 05, 2010 @02:52PM (#33797800)
    Mars, Callisto, Ganymede, Europa, Titan, Pluto, Mercury, Iapetus, Miranda, Charon, Eris and a bunch of other "further shores" I have forgotten the names of that are just a tad closer to home.

    But I agree on your other point, Gliese 581g is, possibly, a truly profound discovery. If improvements in remote sensing and telescopes reveal that this new world has an Oxygen rich atmosphere or other solid indications of life (radio?) then it will likely be the most profound and culturally altering discovery ever made since the development of mathematics and writing.
  • by Anonymous Coward on Tuesday October 05, 2010 @02:54PM (#33797820)

    Only four years before they mapped the earthworm genome it was thought that it wouldn't be possible to do such a thing.
    A few years later they were mapping the human genome.
    It's better to be optimistic and be disappointed, than to be pessimistic and not try.

  • by BJ_Covert_Action ( 1499847 ) on Tuesday October 05, 2010 @02:55PM (#33797830) Homepage Journal
    Sure, chucking a probe 20 lightyears away would be awesome, and if we could scrape together the international will and resources necessary to do that I would be all for such an effort. But what about exploring some of the more exciting areas in our own celestial backyard, if you will?

    To date we have only had landers on a few of our planets. We only have functioning rovers on one. We had an impact probe on only one of the moons circling the gas giants. We have rendezvoused with one asteroid, and we have gotten two probes into the Kuiper belt. So, before we go dumping trillions of dollars (and it will cost at least that much) into a tiny (and it will be tiny) scientific payload to another solar system, can we start funding some serious exploration here first?

    I want to see landers, rovers, and submersibles on Europa, Enceladus, Titan, Ganymede, Io, and Callisto. I want to see regular sample return missions to near Earth asteroids. I want to start a ferry program between LEO and the Earth's surface for more than a handful of elite astronauts. I want to see experimental habitats on the moon, rovers on Venus, probes on Mercury, orbiters around Jupiter, Saturn, Neptune, Uranus, and even Pluto, and I want to have at least ten more robots actively exploring Mars. Don't get me wrong, Gliese 158g is one hell of an interesting planet and we should study it as best as we can with out long range sensors and, as one 'dotter even suggested, perhaps we should try communicating with it. I see no reason to evens start thinking about sending a matter-based payload to that planet, however, until we really take some time and effort to start exploring our own solar system. For as much as we have done here, we still really don't know all that much about our home system. I, for one, am not convinced that there are not colonies of methane-based life on Titan and a whole city of icy fish people swimming under the crust of Europa. Let's not even start talking about the possible cloud people of Venus or the cave-dwellers of Mars...
  • by mdm-adph ( 1030332 ) on Tuesday October 05, 2010 @02:55PM (#33797836)

    They're all too busy watching "Gliesian Shore" to care.

  • Re:Overly pedantic (Score:5, Insightful)

    by TheClarkster ( 1130495 ) on Tuesday October 05, 2010 @02:55PM (#33797842)
    Trust a slashdot reader to miss the entire point and squabble over an irrelevant number.
  • by commodore64_love ( 1445365 ) on Tuesday October 05, 2010 @03:15PM (#33798146) Journal

    And maybe we won't. Ever wonder why we've never visited by aliens? (And I mean an actual visit, with hand-shaking or gun-shooting, not some drunken redneck staring at weather balloons or lights.)

    Maybe it's because the gap across stars is too large to cross, and there's simply no science to bridge the distance. Take Star Trek for example. Completely unrealistic. That one scientist says, "...develop a matter-antimatter drive, and can figure out how to bring along 530 times as much mass in fuel as is contained in the ship and cargo itself." Clearly the enterprise doesn't carry around a fuel tank 500 times itself in size. Instead they run on magic (the fuel never runs out).

    Maybe there is NO science that would allow humans/aliens to cross interstellar space within said species existence. Maybe they're quite literally trapped.

  • by Tablizer ( 95088 ) on Tuesday October 05, 2010 @03:41PM (#33798504) Journal

    ...send our politicians there. []

  • by Anonymous Coward on Tuesday October 05, 2010 @04:30PM (#33799224)

    Animals don't make nutrition. Vitamin D is created by sun exposure in humans and other animals, and is not a significant part of milk until it is added artificially.

    On the subject of an all female crew, don't forget that we can send frozen eggs along with sperm. As long as we have a few females, if they are real troopers, they could each have a baby a year. Each baby would have sperm AND an egg from a different mother and father. The next generation could reproduce with each other safely even if they were born of the same mother, and they could also supplement themselves with more frozen sperm and egg babies for many many more generations.

    This is all assuming we don't have an artificial womb. Imagine sending just the sperm, eggs, robots to set up the environment, and then finally when they get the OK from us, they could raise an entire generation of humans. The robots would feed them, but videos from us that were sent along and keep getting beamed could educate them and teach them to communicate with each other. Of course we would get data beamed back so we could respond, years later.

  • Re:180,000 years (Score:3, Insightful)

    by pixelpusher220 ( 529617 ) on Tuesday October 05, 2010 @05:11PM (#33799932)

    That's exactly backwards. Thanks to special relativity, the faster they go, the slower time is passing on earth relative to them.

    No you have it backwards. As they approach c their time slows down so that c stays c. Meanwhile on earth time is moving along at 'normal' rates which is much faster than on the ship that is going near c.

    The colony ship would only find themselves to have experienced less time than what had passed on earth if they decided to turn around and come back.

    Yes because all relativity effects are only felt on the way back. Facepalm. perhaps you meant they would only realize (as in see it firsthand) the time difference when they returned to earth, but they have indeed experienced less time regardless of whether they go back or not.

  • by Joe Tie. ( 567096 ) on Tuesday October 05, 2010 @07:09PM (#33801324)
    It really is a weird assumption. As if any of us are making a hobby out of hooking up bark controlled shotguns to our dogs. We're a super violent xenophobic ape, it'd be illogical as hell to give that to us unless it came as a double package with genetic engineering for pacifism.

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