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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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  • Re:180,000 years (Score:4, Interesting)

    by D3 ( 31029 ) <daviddhenning AT gmail DOT com> on Tuesday October 05, 2010 @02:22PM (#33797262) Journal
    Assuming it takes 100 years to build everything we need to make this flight, by the time you get there it will be 178,570 years after the group that took 1000 years to build the matter/antimatter ship finished their project.
  • Radio (Score:4, Interesting)

    by mukund ( 163654 ) on Tuesday October 05, 2010 @02:28PM (#33797360) Homepage
    How about sending some targeted "Hello world" transmissions towards that object first? If they have any intelligent life and a SETI program in place, they may hear us and answer back.
  • Communicate first? (Score:5, Interesting)

    by earthloop ( 449575 ) on Tuesday October 05, 2010 @02:29PM (#33797372) Homepage

    Would it not make sense to communicate first? Radio at 20 light years is a 40 year round trip. You never know, somebody might answer with instructions on how to get there quicker.

    Hey! That's given me an idea for a great film. Is Jodie Foster available for the lead?

  • by MozeeToby ( 1163751 ) on Tuesday October 05, 2010 @02:33PM (#33797432)

    I'd really love to see some college actually do a study on if it would be possible or not. It's hard to say without real research just how much and what kind of resources an ark ship would need over those kinds of timescales. What's the theoretical rate of atmosphere loss? How efficiently can waste be recycled and put back into the ecosystem?

    Using a sperm bank to dramatically increase genetic diversity would significantly reduce the minimum size of the crew, an all woman crew would further reduce the size but would probably cause all new problems. A vegan diet reduces the need to support non-human animal mass, but adds a requirement to be able to synthesize some vitamins and proteins. Enough redundant manufacturing to produce spare parts for everything, including the manufacturing facilities. IMO, it looks hard but not impossible with today's technologies.

  • by rotide ( 1015173 ) on Tuesday October 05, 2010 @02:33PM (#33797436)

    What I find exciting is the prospect of a lot of young minds trying to figure out how to get a probe there with the capability of communicating back (within a reasonable time frame) what it finds. And then the science, if it is a habitable planet, of trying to visit it.

    We need a new catalyst to spark imagination and an intense drive to succeed in the sciences.

    Even if it is impossible to venture there, the discoveries and new technologies that we _do_ develop that doesn't quite reach the goal, but is above anything we currently have... Exciting!

  • Re:Laughable (Score:1, Interesting)

    by Anonymous Coward on Tuesday October 05, 2010 @02:35PM (#33797480)

    And you Space Nutters are against life extension research too...

    We aren't, QA. We're hedging our bets. Have you considered that unless you want immortality to be restricted to people with the wealth of Bill Gates, we'll pretty much have to develop a means to get off this rock pretty much the day we develop clinical immortality? The oceans are big, but we went from a billion people to 6 billion people within a century or two without immortality. The oceans just aren't big enough to support a civilization of a trillion immortals.

    Meantime, while someone else works on life extension, we're workin' on making sure there is somewhere to go. Easiest way to do that is have a bunch of frozen cells in the core of a space probe, and lob the probe towards the nearest suitable star, and let the robots wake the cells up in 10-20K years. A ship full of algae could go first, and a ship full of human embryos - woken and taught by robots - could show up a few centuries later.

    We space nutters would also prefer if we get to see the rocks, but in lieu of that we'll settle for a scenario in which someone gets to see the rocks. If, as the Fermi Paradox suggests, we're the first sentient species capable of spaceflight, the galaxy is ours for the taking.

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

    by elrous0 ( 869638 ) * on Tuesday October 05, 2010 @02:36PM (#33797492)
    The numbers are truly staggering. I remember my grade school teacher telling us that we would probably one day live to see spaceships traveling to other solar systems. I think now what a silly statement that was, but as a kid I was all "Yeah! Let's go!" All the Star Trek and Star Wars probably didn't help with the popular understanding either (not that they were meant to).
  • Nuclear propulsion. (Score:3, Interesting)

    by MaWeiTao ( 908546 ) on Tuesday October 05, 2010 @02:36PM (#33797498)

    For now a matter-antimatter drive might as well be a pipe dream. We don't have a way to create antimatter in any meaningful quantity. Using the current process it would take 2 billion years to produce 1 gram of anti-hydrogen. Then there's storage. Anti-hydrogen has been kept from destroying itself for 10 seconds. (Thanks, Wikipedia.)

    Before we start even talking about getting to other planets there are a few things we need to do. We need a space station far more robust than the ISS. One that allows manufacturing in space. Heavy-lift vehicles get all the materials we need into orbit. It's all assembled and launched from space. Needless to say, that's far easier said than done. But if we want to engage in real space exploration I think to start outside of Earth's gravity well. Too much energy is wasted just getting spacecraft into space and building them to survive launch and flight through the atmosphere. Although, I suppose even in space they have to withstand similar loads. But the point is that if you start in space you have many more options.

    And I think it's high time we restarted research into nuclear propulsion.

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

    by ari_j ( 90255 ) on Tuesday October 05, 2010 @02:43PM (#33797632)
    The Helios probes didn't exactly take 3 months to travel 8 light minutes. I'm not sure where you're getting the numbers, but most likely they mean that the probes took 3 months to get from perihelion to aphelion. The article you linked to on Wikipedia claims their speed record to be 0.000234c, which is over 1/5000th the speed of light, around 3 times the speed you quoted. That's only 100,000 years to go 20 light years. Still impractical.

    The real question is the delta-v required to make the trip, including navigation along the way and corrections that must be made due to the impossibility of accurately calculating everything ahead of time. The minimal delta-v solution may indeed be around 180,000 years in duration, although other solutions may become practical with time to reduce that figure. Reducing it to only a few human generations in duration, though, will almost certainly require more than incremental improvements in technology.

    For now, I think we're definitely better off pointing a radio telescope in that direction and trying to see what the early years of MTV were like for the Gliese 581g-icans.
  • by cjonslashdot ( 904508 ) on Tuesday October 05, 2010 @03:26PM (#33798310)

    I remember leafing through the book "The Science of Star Trek", and thinking that the author simply did not have much imagination. For example, the author assumed that a "transporter" would have to "scan" all of one's atoms, in the way that a fax machine scans a piece of paper. Yet, if teleportation is possible, it probably does not involve scanning: it probably involves some kind of quantum entanglement mechanism - and even that assumption is based on the very limited understanding that we have today of how things work and what the universe is made of.

    The fact is, the universe's fabric is so bizarre that we probably cannot imagine how a future race might be able to travel near the speed of light, or at it - or perhaps even beyond it. Going from one place to another might not even involve "travel" as we think of it.

    So to dismiss anything at this point is pointless.

    However, the point about the vastness of the solar system - and the space between solar systems at that - is very well taken. It is beyond comprehension.

    Perhaps when it becomes possible to traverse these distances in some manner, humans will no longer exist in their current form; perhaps we will have long since merged with machines and become something so different from what we are today that we cannot even imagine it.

  • by MichaelCrawford ( 610140 ) on Tuesday October 05, 2010 @03:32PM (#33798394) Homepage Journal
    It would be easier to build a telescope that could resolve the surface of the planet, than it would be to travel there.
  • by CrashandDie ( 1114135 ) on Tuesday October 05, 2010 @03:32PM (#33798404)

    "I don't think you understand the magnitude of the problem." Banks told Cook, "There are fundamental physical limits to the amount of food we can take and the amount of money available to either of us."

    Cook wasn't really listening, just looking through the window, already enamouring the feel of the audacious idea. Seeing his friend take but little to no appreciation from his words of warning, Banks continued.

    "Literally, the only chance we have of finding another continent is to build an entirely new ship that somehow makes this kind of journey feasible. Probably the best bet is to copy it from the Dutch, if any ever bother to visit."

    The fire kept glowing steadily as they both stood, looking outside the window. Neither of them knew how wrong they were in their expectations.

  • by huckamania ( 533052 ) on Tuesday October 05, 2010 @03:39PM (#33798488) Journal

    There is no gap between stars. By the time you get close to exiting our solar system, you will already be closer to a neighboring star then you will be to Sol.

    The idea that we will build a ship to go to another star on a direct route is a child's fantasy, much like terraforming Mars. We need to figure out how to live in space. Once we have figured that out, we can go anywhere or nowhere. The resources in space that are close to the Earth dwarf the resources that exist on this planet.

    What we need to be working on is automated fabricators and such. Propulsion is over-rated. Just start seeding the path with resources from our automated fabs and then when we do want to go somewhere, we can take our time and not have to bring everything with us.

    Gene Roddenberry had it right. We need a wagon train to the stars.

  • Re:Reality check (Score:1, Interesting)

    by Anonymous Coward on Tuesday October 05, 2010 @03:47PM (#33798604)

    Plutos' orbit is 30-49 AU (, and you dropped a zero on the divide.


    49 AU = 0.000774830082 light years (thanks Google)

    20/0.00077... = ~25,812 times as far Pluto.

  • by dpilot ( 134227 ) on Tuesday October 05, 2010 @04:00PM (#33798806) Homepage Journal

    Then there's the other way...

    Well before we have a fraction of the technology necessary to ship our "ugly bags of mostly water" to another star, we'll likely have hit Kurzweil's Singularity, and most notably the ability to extract and run a Turing image. Even if the computer necessary to run that Turing image is the size of a human body, its "life support" will be electricity and temperature control, the hardware can be slowed down during the boring parts of the journey, it can likely stand higher accelerations than bio-bodies, etc, etc, etc. All told, interstellar exploration by Turing images may well be far more likely than bio-bodies. It wouldn't surprise me that not long after we succeed at extracting and running a Turing image, we'll have interstellar capability for those images, even though we'll be a long way from doing so for bio-bodies.

    Of course whether we first do that or render Earth unfit for advanced civilization is anyone's guess. (Environmental collapse rendering the planet nearly uninhabitable for millennia is not uncommon in geological time. The Earth has always recovered - in a few thousand to a few million years.)

  • Re:180,000 years (Score:4, Interesting)

    by dpilot ( 134227 ) on Tuesday October 05, 2010 @04:10PM (#33798916) Homepage Journal

    As long as you're into science fiction...

    Your scenario is described in "Songs of Distant Earth" by Arthur C Clarke. In that book, the root of the solar neutrino problem was that the Sun was burning out. Light from the core takes 1000 years to get to the surface, but neutrinos get out practically immediately. The information that the hydrogen-burning life of the Sun was over hadn't made it to the surface yet. So we figured it out, and realized that we had some 900 years (Evidently the solar neutrino problem had barely started when we discovered it.) to find a new home. Interstellar travel became a top priority very quickly. First ships were slower, later ships were faster. The story takes place when an earlier ship stops over at a planet which had already been colonized by a later ship.

    Or take "Hitchhiker's Guide" by Douglas Adams or "Those Gentle Voices" by George Alec Effinger. Put all of your non-productive people on the first slow ships. Then those that are left can work faster/better on newer, faster ships. In a twist, safe flight for the first slow ships is optional, as are intentional crashes.

  • by David Jao ( 2759 ) <> on Tuesday October 05, 2010 @04:26PM (#33799152) Homepage

    The theoretical speed for a momentum-limited, 100m orion craft would be 3,3% of the speed of light, so... no. No it wouldn't.

    You missed the point completely. 3.3% of the speed of light isn't enough to get there within our lifetimes, but it's a lot faster than the estimate of "180,000 years based on current space flight technology" quoted in the summary.

    And make no mistake, Project Orion is completely feasible with present-day technology. The only reason why people avoid mentioning it is because it contains the dirty word "nuclear".

  • by astar ( 203020 ) <> on Tuesday October 05, 2010 @04:47PM (#33799532) Homepage

    I liked your take on the gap to the stars. The usual argument goes more along the lines if we get to the next star system and colonize, then make some reasonable assumptions on how easy is would be to recurse and maybe we own the galaxy in 10meg years.

    As far as space vs planet, your point has virtue for those who are silly, but you know darn well that we will do both. Who leaves habitat unused? Even the Sahara, which is really sort of an example of the failure so far of whatever ,life oriented deity you like, gets some life and includes humans. To me, it seems quite reasonable to "terraform" local deserts, so why not local planets?

    Here is a sort of terraforming project that has been kicking around since the middle of last century. No interesting tech requirements, just no willpower So. as part of it, you need some new science work, but not new hardware tech. Like most things, getting the concepts right is the hard part. []

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

    by blind biker ( 1066130 ) on Tuesday October 05, 2010 @05:15PM (#33799980) Journal

    Read Mayflower II, an award-winning, excellent short novel by Stephen Baxter, probably the best contemporary hard Sci-Vi writer. The topic is, indeed a generation ship (one where multiple generations have to pass before the destination is reached). It's absolutely perfectly and vigorously on topic for this entire thread and your post in particular.

  • by butalearner ( 1235200 ) on Tuesday October 05, 2010 @07:37PM (#33801704)

    Project Orion actually calls for the use of nukes at launch, too...on the order of 1000 of them just to get to LEO. So yeah, controlling all of those explosions is pretty highly suspect, considering all we've done is prove that graphite-covered steel spheres can survive a nuclear blast.

    A far better plan is colonizing our own Solar System. Perhaps there is an asteroid or moon with sufficient natural resources that it would be better to build and launch the Super Orion from there. Of course, by that time some other technology may render the plan obsolete, but the journey would be worth it.

  • by butalearner ( 1235200 ) on Tuesday October 05, 2010 @08:23PM (#33802144)

    I'm with you on most of that, but unfortunately with limited budget we need some priority. Colonizing our Solar System, to me, should be our top priority, so we should focus on the places where we stand the best chance of building permanent habitats in a relatively short time. The moon, obviously, plus Mars, asteroids including especially Ceres and Vesta, Jupiter's Galilean moons (though probably not Io), and Titan for its nitrogen-rich atmosphere. It will be very interesting when our Dawn spacecraft reaches Vesta in the next couple years and Ceres a few years later.

    Mercury and Venus, unfortunately, are much, much further away from that goal. If only Mercury were tidally locked with the Sun, we might colonize the band where the temperatures are reasonably comfortable. It'd be interesting to send a flyer to Venus, but we simply couldn't survive the atmosphere right now. Orbiters around the gas giants themselves aren't going to help us as much as orbiters that are free to explore their moons. Pluto has New Horizons speeding towards it, so we'll get to find out what interesting properties it has, but we'll likely have something similar much closer to us.

  • by NeMon'ess ( 160583 ) * <<flinxmid> <at> <>> on Wednesday October 06, 2010 @02:16AM (#33804884) Homepage Journal

    Perhaps the poster was confusing the size of the theorized Oort cloud? There may be specks and pebbles of matter orbiting the sun from as far away as a light year.

  • by robertinventor ( 1618655 ) on Wednesday October 06, 2010 @04:49AM (#33805594) Homepage
    Why the hurry? If we learn to live in the Oort cloud, probably with fusion reactors for miniature suns, then humans will spread through the oort cloud and then reach other stars - the Ooort Cloud does spread a long way from the sun, and mingles with the comet clouds of other stars as stars pass each other in the galaxy. In not that long time geologically we will colonise the entire galaxy.

    Seems almost inevitable that will happen if our technology continues to evolve, fusion is hard to do but only on timescale of decades, we are so close to it that it will surely happen quite soon on timescale of centuries. With fusion suns life in the Oort cloud could be very pleasant, probably in spinning space habitats to simulate gravity

    One wonders what could stop this in fact. Once a few comets in the Oort cloud are colonised, hard to think of anything that could stop the process. And is it right for humans to colonise the galaxy? Why have no other alien species done the same and reached us already in the history of the galaxy?
  • Many tiny probes (Score:3, Interesting)

    by Mandrel ( 765308 ) on Wednesday October 06, 2010 @07:30AM (#33806370)

    Yes, I think tiny self-aware probes will be the way we'll do it. A one-gram probe would still require a Hiroshima to get it to .85c.

    You'd be able to launch billions of them, both to target many stars at once, and also to allow the probes to communicate down chains.

    You'd be aiming to impact a planet (make it survivable by building the probe mainly out of diamond), after which the nanotech would sprout and build something better. Rather than a simple scatter-gun approach, the probe could steer as it travels by releasing radioactive decay particles left and right.

    Using this you could expand the front of exploration at .8c, and pwn the galaxy in 100k years.

    Major questions: how to accelerate the probes, and can a .85c impact be survived.

"Never face facts; if you do, you'll never get up in the morning." -- Marlo Thomas