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How to quickly survey an exoplanet before colonization?

  1. Apr 7, 2015 #1
    Assumptions:
    -more or less contemporary technology
    -virgin planet which is glared by lustful humans ;)
    -habitable (oxygen, reasonable temperature)
    -no requirement for 100% certainty, reasonable guess is OK (the point is to find quite good place for colony very soon, not a perfect one in a few years)

    The question is how to check it and what are the possible risk of errors.

    Challenge:
    -not much time, the colonist are on the way
    -do it with limited resources (satellite / aerial photos - OK, deep drilling - would be a challenge)

    1) Landscape, rivers for transport - seems trivial, the only trap that I see are ephemeric rivers/lakes, seasonal flooding
    2) Agricultural / forests - seems and fast OK (risk of poisonous plants, unstable climate)
    3) Earthquakes - by checking active volcanos and marking on map active zones (but I'm not convinced about this idea)
    4) Natural resources, fast idea that I can think of:
    -tracing magnetic anomalies to find big iron ore deposits
    -background radiation to look for fissile fuels
    -any quick way of finding deposits, except of course landing there and checking surface???
     
  2. jcsd
  3. Apr 7, 2015 #2

    phinds

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    Why would colonists be "on the way" if all of the significant issues had not been first scoped out in some way. Are you proposing a suicide mission?
     
  4. Apr 8, 2015 #3

    wabbit

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    Well, there is a project currently which to me doesn't look very far from fitting this prescription, though of course one can see it differently.
     
  5. Apr 8, 2015 #4

    phinds

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    Yeah, I admire their optimism but not their grasp on reality.
     
  6. Apr 8, 2015 #5
    For story reasons they have a nice choice:
    a) stay on a doomed Earth - which more or less count as suicide;
    b) try chances with a soft science ;) way of teleporting in to a far away planet which is supposed to be habitable.

    (
     
  7. Apr 8, 2015 #6

    wabbit

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    Teleportation is one technology i would not be the first to try - my guess is that you would be certain to be killed in your present location, no so much that the reconstruction will work at the destination. Then again, if you're doomed.,,
    But to teleport somewhere you'd need to have installed the receiving apparatus there already.
     
    Last edited: Apr 8, 2015
  8. Apr 8, 2015 #7
    http://en.wikipedia.org/wiki/List_of_potentially_habitable_exoplanets
    I think we need techniques a little better than contemporary in order to have a reasonable survey of an exoplanet. We don't have a good way of measuring the atmosphere or the rock composition. I'd rather take my chances with Mars. At least it is reasonably well surveyed.
     
  9. Apr 8, 2015 #8
    After thinking about realistic technologies, I reached a sad conclusion - any realistic tech is either:
    - boring (what's cool in Orion drive, hibernation and thousand years long journey?)
    - overkill if you start thinking about military application of such tech or that if you can product such insane amount energy then you don't care about looking for Earth like planets any more

    So it's mag... oopsie... psionic teleportation. At least it can work consistently as required by story, and is not any more unscientific than usual FTL drive.
     
  10. Apr 8, 2015 #9

    wabbit

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    Well I don't know how psionic teleportation works, but it sounds cool :)
     
  11. Apr 9, 2015 #10
    Any planet with an oxygen atmosphere would also have life, making sure that it isn't dangerous to the colonists or their crops, et cetera or vice versa would take a lot of time, I don't think bringing colonists directly to the surface would be a good idea.
     
  12. Apr 9, 2015 #11
    So, is it a one way trip? Can they not send a scout forward and report back?
     
  13. Apr 9, 2015 #12
    Yes, I know, how War of the worlds ended. ;) But any ideas how to make the result more moderate? Pollen allergy? Organism that occupies similar niche to locust?

    Yes, one way ticket. Not much time. Everything have to be done in an awful hurry, yes they can scout forward, but could they report back at best in less then a week? ;)
     
  14. Apr 9, 2015 #13

    mfb

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    A planet without life might be easier than a planet with life. We don't have any samples, but given the small amount of stuff humans can live from on earth where we evolved to be able to digest it, I would not bet on using anything extraterrestrial as food supply (unless you find some chemical process to prepare it). Microbes on the other hand are much more flexible in terms of food, and our cells might not even recognize them as something to defend against.

    You probably want sources of hydrogen, oxygen, carbon and nitrogen. The average temperature and daily variations should be reasonable. Surface gravity should not be too different from earth. Liquid surface water would be great. Things that are easy to observe from an orbit around the planet, but hard to do from earth (we should get many atmosphere spectra with the new large telescopes in the next 10-20 years, but don't expect too much). You probably want plate tectonics and some more planetary chemistry to get deposits of various chemical elements in the crust.
    The more tools and materials you can bring from earth the easier will building a colony be, of course.
     
  15. Apr 11, 2015 #14
    You don't recognize this process??? It's called alcohol fermentation :D :D :D (technically speaking that should work...)
    Honestly - hard to say. It's also possible that our immune system would just shoot to everything that moves, while, local microbes would face awful problem to cross specie barrier. (which of course may be possible anyway: http://www.forbes.com/sites/paulrod...ion-year-species-barrier-to-infect-honeybees/ )

    I did my homework here (in short):
    -tidally locked planet around tiny red dwarf
    -icy water world
    -3 times higher atmospheric pressure (should make airships viable, forces any vehicle to be really aerodynamic or slow)
    -binary system, there is additional sun like star that provides 1/3 of heat (yes, I needed an explanation of what prevents accumulation of frozen CO2 on the dark side of the planet)
    My question considered just possibility to make a quick survey at start. Because of low population, there would be high importance of waterways (no investment on roads) and hydropower (very cheap in build in good place, Aswan dam paid off itself in a few years). So I assumed consequently the main city would be located in temperate zone, at a big river.
    Later I started to wonder to think about different factors based on additional survey:
    -ore;
    -seismically dead zone.
    If that could be found quickly - that would have to be included and force me to reshape a bit my plan.
     
  16. Apr 15, 2015 #15
    What level of detail?
    A few sattelites can do a pretty good job of surveying the planet in a few days if not a few hours.
    More detailed surveys than that takes an unknown amount of time as more detail is "encountered as you go".
    We're still not done with a 100% complete survey of earth yet with our tech so >.>
     
  17. Apr 15, 2015 #16
    Even if you send a scout, there's no way for the scout to report back without some FTL communication (assuming they can't just teleport back). Another issue is that we can only view exoplanets as they were in the past, unless we have some two way FTL. Of course, if you have two way teleportation, that kinda changes everything. Suddenly, distance means nothing, and we can quickly explore everything we care to.
     
  18. Apr 15, 2015 #17

    DaveC426913

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    What is the range of outcomes for the survey? What alternatives are available if a given planet turns out not to be acceptable?

    This is not a trivial question. If the colonists are indeed on their way, and there are no other systems within 100 light years, well guess what - this planet just got the green light be default!

    So, any consideration of red light versus green light must take into account how viable any alternatives are.

    If no alternative are forthcoming, is there any point in doing the survey at all? (Of course, you could always tell the colonists that you did the survey. They might not be around long enough to complain...)
     
  19. Apr 16, 2015 #18

    wabbit

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    Interesting plot twist:)
     
  20. Apr 16, 2015 #19
    By story requirements - effectively no choice at that moment. It's only question where to land.
     
  21. Apr 16, 2015 #20

    DaveC426913

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    Ah. That simplifies things immensely.

    It pretty much comes down to weather/seasons and geography.

    In that sense, the desirable locations on the planet will be similar to the desirable locations on Earth*.
    temperate clime, no extremes, access to water, but not near the planet's hurricane zones (which are the same as Earth). Access to oceans, from a sheltered harbor**.

    *OK, notwithstanding Florida

    ** I think. Not sure if the need for oceans is the same. That grew organically from Earth's first transportation. A modern colony might actually be safer inland.

    Then again, how reliable is their technology (machinery)? Do they have to worry about replenishment shipments stopping, forcing them to subsist on native resources? Is there a risk of technology collapse, meaning they may have to have low-tech/no-tech backup options?
     
    Last edited: Apr 16, 2015
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