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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

    Khashishi

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    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

    Khashishi

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    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

    Khashishi

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    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
  22. Apr 17, 2015 #21
    Already on Earth sea transport is the cheapest. In this case there is a problem of low population, which makes heavy infrastructure investment impossible, so for me its water transport by default.

    I'd think about selecting for landing climate like Mediterranean, because even without housing one would not die easily there.

    Early XXIst century.

    They don't have to worry, they know about being cut off almost immediately.

    This collapse and recovery is the big part of the story.

    The bad things:
    -tiny population (like 1 mln), say goodbye to economics of scale
    -very low amount of supplies (limited transport capability - had to choose between people and equipment)

    The good:
    -well selected people - so educated, disciplined, hard working, healthy (at start), without easily detectable genetic diseases
    -the planet is not so bad, while for such tiny group the natural resources are abundant

    Any suggestions about the low tech back up option?
     
  23. Apr 17, 2015 #22

    wabbit

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    With no more supplies coming they will have no choice but to go low tech. High tech means such a huge number of things and large capital investment, they would have no chance to sustain it - how would they run semiconductor fabs? They should use wisely the high tech capital they bring with them for it will decay and they won't be able to replace it. Their last computer will be a device so highly prized a religion will be built worshipping it after it has stopped working:)

    Most important for them in my view is so start agriculture, and try building the plants that make the parts that make basic agricultural machinery. Things like that, though "plants" is probably too ambitious, workshop maybe.
     
  24. Apr 17, 2015 #23
    For start colonizers have got a good source of highly protein food - megafuna (yes, luckily chirality fits). A few good shots (or even a spear thrower) and you have a few tones of meat, that has to be processed quickly. With limited amount of effort, you can feed many of people in this way. Just you don't slain females, to allow the specie to regenerate.

    Iron can be easily smelted by everyone - just ask Chinese from Mao's era ;) More seriously - a poor quality one it's not so complicated to produce in really primitive conditions. There is really plenty of wood and untapped iron ore resources.

    There are plenty of rivers to build dams and start using hydropower. High tech - no, but XIXth century tech does not sound implausible.

    I tried to make a trivia econometric model. As starting point I used economic level of the poorest subsidence farming countries (comparable to past Europe a few centuries ago). Then I assumed that hypothetical top possible GDP growth is around 20%/year (for model purposes, not actually happening).
    (they are not tribesmen, they are highly educated, they are disciplined and they bring technology, they just need capital).

    As model I assumed modified logistic function, with in long run increasing the limit. I assumed that losses caused by lack of scale economics, are being compensated by ultra high saving rate, good but ruthless governance and brutal elimination of any inefficiencies. (keeping person in prison for years is ineffective, punishing with electroshock not ;) ). Conclusion for such model was a poor first world in not much more than 25 years. Not bad.

    Unless the assumptions are insane, then actually I think that computer would not be worshipped. I think more in line of being kept in museum, near other artifacts from the old world, like the landing devices. And kids would make photos with their all identical, mass produced phones.
     
  25. Apr 17, 2015 #24

    wabbit

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    I think you underestimate the capital accumulated and complexity of a high tech society. Mass produced phones require so many things, starting as I mentionned above with semiconductor fabs, that i cannot imagine a 1M population quickly reaching that stage. I also think your prescription for an authoritarian society engineering growth will work only for a short time, but this may be part of the plot - the rise and fall of the techno-USSR:)

    But who knows - anyway it's your book, you decide your economics:)
     
  26. Apr 18, 2015 #25
    Compare the first settlers of various overseas colonies.
    Jamestown starved - partly through quarrel with native humans. Out of 500 settlers, just 60 survived to be bailed out 3 years after arrival.
    Pilgrim Fathers suffered scurvy and illnesses - 53 out of 102 survived, and just 4 adult women out of 18. But they were out of trouble by the first Thanksgiving 1621, less than 12 months after arrival.
    Winthrop Fleet founded Boston with 800 people in 1630. And they did not starve.
    First Fleet arrived in Botany Bay in 1788 with about 1500 people surviving on board. They actually twice found the chosen site ill-suited. First, Botany Bay was open to storms, shallow water near shore, scarce fresh water and apparently infertile sandy soil. 8 days later, on 26th of January, the fleet left Botany Bay and sailed to Sydney Cove. There they did find sheltered deep water and fresh water Tank Stream.
    They did run short of food by 1790, though not to mass mortality. Also, Sydney did still share the problem of infertile sandstone soils. They did seriously consider moving the settlement second time, to Parramatta where they had finally found more fertile shale soils - but eventually decided to keep Sydney as a seaport.

    So... How would a 2015 fleet of 1000 people, or 100 people, pack up supplies to settle an empty continent or planet if they reasonably expect no resupply for years, or ever?

    If they plan on farming then they need seeds, plus a food supply to eat for themselves for some months (till first harvest). That´s a minimum. If that first crop fails because they have misjudged the soil or climate or local microflora then they might not have the seed to try again, nor food to survive until then.

    If the early exploration discovers that the soil is unsuitable, they might decide to pack up their remaining food supplies for the voyage back, and abandon the sown fields they expect to fail (because if they waited to see them fail, they would no longer have food left for voyage). Alternatively, an advance party might alert the main fleet that the originally planned spot is unsuitable and direct them to a better place elsewhere on the continent/planet, rather than waste seed on fields which would fail.
     
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