Potential Habitable Planets

Discussion in 'Science and Technology' started by Into Darkness, Dec 10, 2013.

  1. Edit_XYZ

    Edit_XYZ Fleet Captain Fleet Captain

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    There's a problem with this conjecture: Carbon chemistry has advantages silicon, etc lacks:
    http://en.wikipedia.org/wiki/Hypothetical_types_of_biochemistry#Silicon_biochemistry
     
  2. Into Darkness

    Into Darkness Captain Captain

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    If it was easy for life to evolve that wasn't carbon based we'd surely have seen it by now. Life in general, at least any more advanced form of life such as animal or human seems to require heat, light, water, oxygen and protection from space radiation. There are so many factors that add up together to allow advanced life that Earth has to be very very rare.
    It's possible some form of life evolved on planets less fortunate than Earth where it's not as "paradisaical" but those worlds would still require a bare minimum of factors such as not too hot and not too cold, a protective magnetic field.
     
  3. CorporalCaptain

    CorporalCaptain Admiral Admiral

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    With zero examples of extraterrestrial life of any kind, there's no reason whatsoever to agree with this assertion.
     
  4. Into Darkness

    Into Darkness Captain Captain

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    This solar system has 8 main planets, several dwarf planets and a multitude of moons, some have atmospheres, some have decent gravity levels, some have water . Not one of them other than Earth has life on them let alone advanced forms of life, which goes to show that environments not like Earths are not suitable environments for life.
    Our solar system alone is statistical proof that life doesn't and cannot just spring up in any old kind of environment, a multitude of specific factors are required and such factors combined together must surely be rare.
     
  5. Spider

    Spider Dirty Old Man Premium Member

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    Or to disagree with it. Making assumptions about what you do not have scientific data on is bad for both sides. I think what we know, which isn't as much as we'd like to think, that since the evidence of other planets around other stars is proven, we can safely speculate that life does exist elsewhere other than earth just given the sheer billions upon billions and billions of stars in the universe.

    But it may be so rare that we might not find it at all unless we somehow avoid extinction and learn the secrets of FTL travel.
     
  6. CorporalCaptain

    CorporalCaptain Admiral Admiral

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    On the contrary, there are excellent reasons to disagree with Into Darkness's assertion.

    Evidently, the point of his assertion is to argue that not yet having observed non-carbon-based life is a reason to suppose that it is harder for it to evolve than it is for carbon-based life. That's simply absurd, because, if it were valid, then we could apply a similar argument to conclude that extraterrestrial life of any kind is a rare thing. Based on the evidence, or rather the lack thereof, that's a totally bogus conclusion, because we simply have not ascertained how many stars in the galaxy have planets or moons with life on them. Our ability to observe the universe around us still doesn't let us do that. We don't even yet have reliable estimates. Since we are presently incapable of determining how much extraterrestrial life there is of any kind, we are incapable of determining how much of it is non-carbon-based, based on whether we directly see it.

    That doesn't mean that there isn't reason to expect more carbon-based life than non-carbon-based life. I agree that there are a lot of good reasons to doubt that non-carbon-based life is easy to evolve, even assuming it's possible, however our failure so far to observe any isn't one of them.

    Well, yeah, but what I'm saying is that Into Darkness's assertion isn't really a neutral assertion. In grossly overestimating the significance of our observations to date, it's really biased to the point of being fundamentally flawed.

    I'm just going to stop you right there, and refer you to this page.

    No. There's still a lot we don't know about our solar system, including whether life arose on any other body in it besides Earth sometime in the past and then went extinct.
    Well, we really don't know that yet, which is why we continue to look for things like planets around other stars and learn all we can about them, and it's also why we continue to theorize about how evolution works, how life began on Earth, and what other forms of life might exist.
     
    Last edited: Dec 17, 2013
  7. rhubarbodendron

    rhubarbodendron Rear Admiral Rear Admiral

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    Also, there's the question: would we recognize extraterrestrial life as such if we encountered it? It might be very very different from what we know. Sometimes it's already quite difficult to spot certain lifeforms on our own planet:
    Would you recognize this as a butterfly or find the locust?

    [​IMG] [​IMG]
    and how about these?
    [​IMG][​IMG]
    (solution: red algae (Hildenbrandia spec.) and flagellate algae (Ceratium hirudinella))

    These advantages or disadvantages depend on the point of view. They apply only if you judge by our standards (i.e. the p.o.v. of a carbon-based organism in a watery environment). Life forms based on other elements might perhaps not share our own definitions of life and of advantages nd they might have a totally different way to store genetical information (or have no genes at all but something different).
    It's a cool link, though, and they do make a lot of excellent poins there! Thank you for sharing! It's not available in my language and I would never have found it.
     
    Last edited: Dec 17, 2013
  8. scotpens

    scotpens Vice Admiral Admiral

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    Hey, I resemble that remark!

    [​IMG]
     
  9. Edit_XYZ

    Edit_XYZ Fleet Captain Fleet Captain

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    About the link, you're welcome.

    About my assumptions ("standards", as you post-modernistically try to put it):
    It's mainly one assumption - that life is informationally highly complex, and, in order to exist, atoms (or equivalents) that can combine in highly complex, stable molecules are needed. Carbon and water are very good at making complex molecules, while having almost none of the disadvantages other proposed chemistries have.

    Did you know that like is the most informationally complex phenomenon in the universe? That the universe has a single set of laws of physics - and chemistry?

    A secondary assumption is that life needs energy (as in, low temperatures mean a VERY slow evolution, etc)
     
    Last edited: Dec 18, 2013
  10. rhubarbodendron

    rhubarbodendron Rear Admiral Rear Admiral

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    I beg to differ. Life needs as you correctly say energy. But that energy needn't necessarily come from warmth. Quite a lot of organisms on our own planet live and propagate in zones that are far below freezing point. The glacier flea, to name only one. Krill lives and thrives in waters that are colder than 0°C and there is such a lot of it that several species of whales, the biggest recent animals, feed exclusively on it (and quite a lot of other animals too). And a surprising number of algae lives on snow and on glaciers, including those in the Arctic.

    I very much agree about chemistry being the same everywhere (though it would appear by some experiments made on the ISS that certain reactions change their mechanisms - and their outcome - with a lack of gravity). You certainly are right about carbon being the most reactive element of the given options. Yet, even on our own planet there are organisms with a silicate skeleton, such as all Bacillariophycea, many Rotatoria, Dinoflagellata and most sponges. And even many higher plants have silicate crystals in their cells (Clivias, for example).
    You will notice that all the life forms with silicate skeletons are planctic and very small. So very obviousely there are limitations to the use of silicium-complexes in organisms. Yet it's not completely unheard of.
     
    Last edited: Dec 18, 2013
  11. scotpens

    scotpens Vice Admiral Admiral

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    Maxwell Montes? Wasn't he a popular Cuban bandleader back in the '50s? :p
     
  12. gturner

    gturner Admiral

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    Venus has a bunch of very odd names. Aside from three features named after men, all the mountains are named after female deities from a wide variety of cultures, giving us gems like Yunya-mana mons, Wyrd mons, Waka mons, Laka mons, Ozza mons...
     
  13. rhubarbodendron

    rhubarbodendron Rear Admiral Rear Admiral

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    that's interesting. Do you happen to know why there are the three male exceptions?
     
  14. gturner

    gturner Admiral

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    Some of the history of the names is in the Maxwell Montes wiki.

    Alpha and Beta Regio are huge highland regions that were discovered by radar earlier in the 1960's, and at that time they just denoted the two features with Greek letters.

    List of Montes on Venus.
     
  15. rhubarbodendron

    rhubarbodendron Rear Admiral Rear Admiral

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    Cool :) Actually, Mr. Maxwell is the only exception since the Latin word Regio (region, area) is a female noun.
    (LOL who'd have thought that after 35 years I might need my Latin again as my old teacher always predicted! - Life itself is pretty sarcastic at times, isn't it? :D)
     
  16. iguana_tonante

    iguana_tonante Admiral Admiral

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    All that, and miss the obvious mons veneris joke...
     
  17. gturner

    gturner Admiral

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    I figured it was too easy. Instead, I present this illustration of the risks inherent in lunar exploration.

    [yt]http://www.youtube.com/watch?v=9WoM2bHfr48[/yt]
     
  18. Metryq

    Metryq Fleet Captain Fleet Captain

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    That's your entire reply? Don't be so condescending. You don't have to be sold on plasma cosmology, but if you're honest, you'll admit to the various ways the gravity-driven fusion model of the Sun doesn't work. Don't confuse conjecture with fact.
     
  19. iguana_tonante

    iguana_tonante Admiral Admiral

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    Yes.
     
  20. rhubarbodendron

    rhubarbodendron Rear Admiral Rear Admiral

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    That's a bit of a meagre reply, in both instances. Please elaborate. If you don't explain what you mean you can hardly expect to convince anyone of your view (which usually is the point of a discussion) nor will anyone take you serious (which I daresay would hurt your ego). Just posting to say "no" or "yes" bears the danger to be interpreted as spamming.

    (inoltre: se siete così pigri, la Befana non vi farà visita :p)