Stories
Slash Boxes
Comments

SoylentNews is people

posted by chromas on Tuesday September 10 2019, @05:55AM   Printer-friendly

Anonymous Coward writes:

https://www.businessinsider.com/alien-civilizations-may-have-already-colonized-galaxy-study-2019-8

The Milky Way could be teeming with interstellar alien civilizations — we just don't know about it because they haven't paid us a visit in 10 million years.

A study published last month in The Astronomical Journal[$] posits that intelligent extraterrestrial life could be taking its time to explore the galaxy, harnessing star systems' movement to make star-hopping easier.

The work is a new response to a question known as the Fermi paradox, which asks why we haven't detected signs of extraterrestrial intelligence.


Original Submission

 
This discussion has been archived. No new comments can be posted.
Display Options Threshold/Breakthrough Mark All as Read Mark All as Unread
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
  • (Score: 2) by NotSanguine on Tuesday September 10 2019, @07:55PM (5 children)

    by NotSanguine (285) <NotSanguineNO@SPAMSoylentNews.Org> on Tuesday September 10 2019, @07:55PM (#892329) Homepage Journal

    This fragmentation makes you wonder again why they haven't conquered the entire galaxy. "They aren't from our galaxy or even close" is one possible answer, if not a satisfying one.

    Interestingly (and oddly, given that exactly no one -- well, except me -- bothered to put any focus on the paper TFA was based upon, and the hypotheses therein) the authors of the paper being reported are *attempting* to explain exactly that.

    They posit that much of the galaxy may well be inhabited via colonization by spacefaring civilizations, but that the distributions of habitable star systems and the movement of star clusters may keep us from detecting them, and them from coming here.

    From the paper's abstract:

    We find a range of parameters for which 0 < X < 1, i.e., the Galaxy supports a population of interstellar space-faring civilizations even though some settleable systems are uninhabited. In addition we find that statistical fluctuations can produce local overabundances of settleable worlds. These generate long-lived clusters of settled systems immersed in large regions that remain unsettled. Both results point to ways in which Earth might remain unvisited in the midst of an inhabited galaxy. Finally we consider how our results can be combined with the finite horizon for evidence of previous settlements in Earth's geologic record. Using our steady-state model we constrain the probabilities for an Earth visit by a settling civilization before a given time horizon. These results break the link between Hart's famous "Fact A" (no interstellar visitors on Earth now) and the conclusion that humans must, therefore, be the only technological civilization in the Galaxy. Explicitly, our solutions admit situations where our current circumstances are consistent with an otherwise settled, steady-state galaxy.

    It seems to me that this is an interesting hypothesis. What's more, it adds additional variables (e.g., the relative movements of stars/star clusters, and the potential distributions of habitable systems in the galaxy) to add more nuance to the discussion about why we haven't detected other civilizations.

    --
    No, no, you're not thinking; you're just being logical. --Niels Bohr
    Starting Score:    1  point
    Karma-Bonus Modifier   +1  

    Total Score:   2  
  • (Score: 2) by takyon on Tuesday September 10 2019, @08:21PM (1 child)

    by takyon (881) <reversethis-{gro ... s} {ta} {noykat}> on Tuesday September 10 2019, @08:21PM (#892350) Journal

    We currently have stars coming closer to us [wikipedia.org]. If we can barf humans at those stars, they will eventually be carried tens or hundreds of light years away from Earth, and they can spread to other nearby stars. Given enough time, the galaxy is ours. Or somebody's.

    It is a big galaxy though, with a mass / number of stars that has been revised upwards [skyandtelescope.com]. Maybe there are pockets of pristine galaxy waiting to be conquered.

    --
    [SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
    • (Score: 2) by NotSanguine on Tuesday September 10 2019, @08:58PM

      by NotSanguine (285) <NotSanguineNO@SPAMSoylentNews.Org> on Tuesday September 10 2019, @08:58PM (#892372) Homepage Journal

      Absolutely. And if it weren't for the risk of Kuru [wikipedia.org], I'd offer to barf such humans up myself.

      As you're well aware, there are significant challenges to human (and alien) interstellar spaceflight, like constant boost drives, using ambient hydrogen for fuel, efficient life support systems, appropriate shielding at such high velocities, etc., etc., etc.

      However, those are mostly (note I said "mostly") engineering issues rather than ones of basic science. As such, it seems likely that such voyages will be possible in the (not so near) future.

      Constant acceleration at 1G (9.8m/s2) approaches the speed of light in less than a year. With initial acceleration at 1G, coasting and then decelerating at 1G, would take ~10-15 years to Alpha Centauri.

      With future advances in living/collecting raw materials/construction/engineering in space, it would also be possible to build space/asteroid/moon based colonies where there are no habitable planets, thus extending the range of colonization each time such a colony (space-based or on a habitable planet) is established.

      I'm just sorry I wasn't born in an era where this could be accomplished.

      The paper referenced by TFA gives an interesting and nuanced counterpoint to the Fermi Paradox. Are the hypotheses in the paper correct? We don't have nearly enough data or the means to collect such data to confirm or refute them. As such, it's all just speculation (as is the Fermi Paradox, I'd add).

      But it is quite interesting, IMHO.

      --
      No, no, you're not thinking; you're just being logical. --Niels Bohr
  • (Score: 2) by HiThere on Tuesday September 10 2019, @08:53PM (2 children)

    by HiThere (866) Subscriber Badge on Tuesday September 10 2019, @08:53PM (#892367) Journal

    That theory has benefits, but it seems to assume that civilizations will continue to be based around planets, which seems to me dubious. And it doesn't explain the lack of "von Neuman machines" doing the exploring. I think a better question is "If they had been here, how would we know?".

    Most people seem to be fantasizing about FTL spaceships, but they seem dubious to me. And something, be it a machine or a society, that is adapted to traveling for centuries, at the minimum, in interstellar space isn't going to be attracted to moving to a planet. Paying a short visit, perhaps, but even that's dubious.

    FWIW, if they ARE biologically similar to us to the point of having life based on amino acids, I would expect that exposure to Earth's atmosphere would be likely to set off anaphylactic shock.

    --
    Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
    • (Score: 2) by NotSanguine on Tuesday September 10 2019, @09:17PM

      by NotSanguine (285) <NotSanguineNO@SPAMSoylentNews.Org> on Tuesday September 10 2019, @09:17PM (#892383) Homepage Journal

      That theory has benefits, but it seems to assume that civilizations will continue to be based around planets, which seems to me dubious. And it doesn't explain the lack of "von Neuman machines" doing the exploring. I think a better question is "If they had been here, how would we know?".

      I'd say that it's not a theory (in the scientific sense), but a hypothesis which cannot currently be tested.

      As for vonNeumann machines, how do you know they don't exist?

      A fair point. However, the hypothesis in the paper (that our area of the galaxy has enough "deserts" around our local, perhaps 100 cubic light-years, make exploration/colonization of our part of the galaxy unattractive). could explain why we haven't seen evidence any extra-solar visitors.

      Most people seem to be fantasizing about FTL spaceships, but they seem dubious to me. And something, be it a machine or a society, that is adapted to traveling for centuries, at the minimum, in interstellar space isn't going to be attracted to moving to a planet. Paying a short visit, perhaps, but even that's dubious.

      As for FTL, the *very* theoretical Alcubierre drive aside, it is, as you say, a fantasy. But given cosmological time scales, colonization (whether based in a gravity well or in space habitats) of significant portions of the galaxy is certainly a possibility (see the latter part of my reply to Takyon [soylentnews.org] for some thoughts on how that could happen).

      What's more, travel might not be on the order of centuries at all. Each new settlement in a new star system would expand the range of further colonization, on the order of ten or so light-years.

      FWIW, if they ARE biologically similar to us to the point of having life based on amino acids, I would expect that exposure to Earth's atmosphere would be likely to set off anaphylactic shock.

      That's entirely possible. Perhaps even likely. But it isn't relevant (IMHO) to the idea of leapfrogging star systems to colonize significant portions of the galaxy.

      --
      No, no, you're not thinking; you're just being logical. --Niels Bohr
    • (Score: 2) by NotSanguine on Tuesday September 10 2019, @11:22PM

      by NotSanguine (285) <NotSanguineNO@SPAMSoylentNews.Org> on Tuesday September 10 2019, @11:22PM (#892447) Homepage Journal

      That theory has benefits, but it seems to assume that civilizations will continue to be based around planets, which seems to me dubious.

      I was thinking about this statement and it occurs to me (I'd have added this to my earlier reply, but I didn't think about it then) that it's not so much that civilizations are or will continue to be based around planets, but rather around the stars they orbit. The star can provide the energy required and the debris around it (generally referred to as planets/asteroids/comets/etc.) can provide raw materials to build livable habitats.

      If a planet is/could be habitable, it could be used as such. However, it's just (and perhaps more) likely that a spacefaring civilization would be more interested in stable stars with a minimal radiation fluctuations and planets with stable orbits within its habitable zone than "habitable planets."

      Colonization doesn't necessarily mean farms and fisheries on a planet with a nitrogen-oxygen atmosphere. It could be just as effective with a (or, more likely tens of them) space-based habitat.

      Given that interstellar travel will take decades even for relatively close stars, the technologies for space-based construction, life support and other basic living requirements would have been long addressed by any civilization with the capability to send living beings to other stars.

      --
      No, no, you're not thinking; you're just being logical. --Niels Bohr