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The Disappearing Universe 358

Posted by Soulskill
from the and-for-my-next-trick dept.
StartsWithABang writes: "If everything began with the Big Bang — from a hot, dense, expanding state — and things have been cooling, spreading out, but slowing down ever since, you might think that means that given enough time (and a powerful enough space ship), we'll eventually be able to reach any other galaxy. But thanks to dark energy, not only is that not the case at all, but most of the galaxies in our Universe are already completely unreachable by us, with more leaving our potential reach all the time. Fascinating, terrifying stuff."
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The Disappearing Universe

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  • by Cardoor (3488091) on Wednesday June 04, 2014 @07:17AM (#47163287)
    one of the allures for me (and i think a lot of people intrigued with cosmology) is how we can interpret the findings as a macrocosm for our own personal microcosm of awareness and being.

    the fact that seemingly inherent in our physical universe is a doctrine of the futility of outward movement (vis a vis reaching a sense of completion or boundary), to me, points to the individual quest for seeking oneself by focusing internally.
    • Re: (Score:2, Insightful)

      by Anonymous Coward

      one of the allures for me (and i think a lot of people intrigued with cosmology) is how we can interpret the findings as a macrocosm for our own personal microcosm of awareness and being.

      the fact that seemingly inherent in our physical universe is a doctrine of the futility of outward movement (vis a vis reaching a sense of completion or boundary), to me, points to the individual quest for seeking oneself by focusing internally.

      consider as well that as our galaxy redshifts from many possible planets of life we will never gain the knowledge of the inhabitants of those worlds, and by the same logic they could never invade ours.

  • terrifying? (Score:2, Insightful)

    by stenvar (2789879)

    Really, folks, you need to stop being terrified by everything.

    • by 140Mandak262Jamuna (970587) on Wednesday June 04, 2014 @07:37AM (#47163415) Journal
      Actually this theory says the number of things that could terrify you is disappearing fast. So instead of being comforted by this fact, they are being terrified of running out of things that could terrify them. Universe does seem to be weirder than what you can imagine, indeed!
    • Re: (Score:2, Insightful)

      by Anonymous Coward

      Seriously. Dark energy is hypothetical.

      Heard it all before. Earth is flat, humans flying is impossible, break the sound barrier and you die, yadda, yadda...

      • Re:terrifying? (Score:5, Insightful)

        by Shadowmist (57488) on Wednesday June 04, 2014 @08:37AM (#47163753)

        Seriously. Dark energy is hypothetical.

        Heard it all before. Earth is flat, humans flying is impossible, break the sound barrier and you die, yadda, yadda...

        If you don't understand the difference between a line of uninformed idiots who kept saying "You can't have a rocket in space because there would be nothing to push against", displaying complete ignorance of Newton's laws, and the limits which are the consequence of well-reasoned scientific models such as C being an absolute limit of material acceleration, then you flat out don't understand the difference between a scientific approach and simply drawing limits out of your butt.

    • Imagine how many quadrillions of intelligences exist in a galaxy the size of the milky way. Imagine how many of them will be destroyed by relativistic jets [nationalgeographic.com]

      • If they are really intelligences, they would be gone before the jet starts spraying.

        As for dark matter, that is probably just intelligences shielding off their stars with energy-collecting spheres.

  • Not so quick (Score:5, Insightful)

    by Anonymous Coward on Wednesday June 04, 2014 @07:33AM (#47163383)

    Physics graduate student here, and I'd just like to bring something into context before any ./ readers begin an existential crisis.

    We don't *KNOW* anything about the dark matter/energy hypothesis yet. They are not well accepted theories like (classical) gravity or electromagnetism, but rather the best answer to questions we don't have any other way of approaching.

    Warning: if you subscribe too heavily to these ideas now, you'll be way, way off base later when science starts finding better answers to the accelerating universe and other open questions. This stuff is great for discussion about philosophy and science fiction, but it is far from well accepted science.

    • Re:Not so quick (Score:4, Insightful)

      by NotDrWho (3543773) on Wednesday June 04, 2014 @07:50AM (#47163487)

      From every description I've heard of "dark energy" it sounds like a kind of place-filler variable for something--as in, "This equation only works if we put in X, but we have no idea what X is."

      • by thrich81 (1357561)

        Maybe so, but that's almost exactly the same situation as when neutrinos were hypothesized to make the equations of some nuclear decays balance out.

      • Re:Not so quick (Score:5, Interesting)

        by bbasgen (165297) on Wednesday June 04, 2014 @10:05AM (#47164359) Homepage

        From every description I've heard of "dark energy" it sounds like a kind of place-filler variable for something--as in, "This equation only works if we put in X, but we have no idea what X is."

        Physicists brought us the dark energy hypothesis, not mathematicians. This is an important distinction: dark energy is not used to solve an equation, rather it is a phenomenon that we can indirectly observe.

        Black holes, Dark energy, Zero point energy -- there are so many nascent concepts that hint at great disruption to our theories but that have not had the time to sort themselves out. Humanity rigorously worked on the concept of gravity for several hundred years before we had our Einstein.

      • Best description I have is that dark energy isn't the explanation, it's the description of the problem.

    • by Bengie (1121981)
      I was under the impression that Dark Matter and Dark Energy were completely unrelated. I was also under the impression that Dark Matter, whatever it is, is somewhat well accepted because of our understanding of electromagnetism, and that we know there is mass, but we also know it does not interact with photons, and we haven't detected any interactions with normal matter.
      • by HiThere (15173)

        We aren't even sure that they're unrelated. If gravity needs to be redone, the change might include both of them (or parts of both of them), e.g.

        OTOH, coming up with something better than "We can't actually see anything causing these effects, but we see these effects..." is quite difficult.

        • by Bengie (1121981)
          We see this effect in hundred million light year wide voids in space. Visibly empty, we can see galaxies way way off in the background, yet LARGE amounts of gravitational lensing, and we know that it's not caused by black holes.

          They are nearly 100% certain that there is galaxy amounts of invisible mass in these voids that cannot be seen. We can't detect dust of any kind, we can't detect black holes, yet we can detect huge amounts of mass. At this point, it is a fact that there is invisible mass.

          Is it t
    • I agree with you there, but any time I try to start the discussion with scientists at Fermilab, I've run into brick walls. They all have bought into dark energy as if it were as secure as our understanding of gravity.

      Perhaps where you work it's not as well accepted, but in the little corner of the real science world I know, dark energy is some kind of science gospel.

      • I find that disturbing. A good scientist should neither eschew a decent hypothesis/theory nor espouse it as dogma.
    • +1

    • "Warning: if you subscribe too heavily to these ideas now, you'll be way, way off base later when science starts finding better answers to the accelerating universe and other open questions. "

      Every damn hypothesis we have are only good as long as we do not find any better answer. Even the one you call better supported. Heck, 150 years ago you would probably have put newton in your list.

      It is the basic reality in physic that we use what we have as hypothesis until a better theory or falsifying data com
  • by TrollstonButterbeans (2914995) on Wednesday June 04, 2014 @07:37AM (#47163419)
    Much of the idea of wormholes came from the idea that universe might be spherical in topography --- like a hypersphere --- and a wormhole could poke through the hypersphere to create a shorter distance than even a line segment from Point A to Point B.

    http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question35.html
    http://en.wikipedia.org/wiki/Shape_of_the_universe

    But measurements are looking like the universe is flat.

    You never know what scientific discoveries the distant future could hold, but at the moment it looks bleak for the concept of wormholes since the universe doesn't seem to be a hypersphere at all.
    • by TeethWhitener (1625259) on Wednesday June 04, 2014 @08:27AM (#47163687)
      Space appears flat on a global scale, but locally, it is highly curved around massive objects, especially around objects like black holes. Nothing we've observed so far strictly prohibits our universe having some sort of locally nontrivial topology like a wormhole. Keep in mind, also, that our observable universe is what appears globally flat. If cosmic inflation is right (and it's looking like it probably is), the actual extent of the universe could easily be 20-30 orders of magnitude larger than what we see, in which case, the universe could be highly curved on those scales and still appear quite flat to the best ability of our observations.
      • by rotenberry (3487)

        I do not believe that what you wrote is correct.

        Empty space is globally flat, but because gravity is a force with unlimited range no universe with any mass in it is globally flat.

        At small enough scale every spacetime is locally flat, although that scale may be very small near a black hole. Only at the location of the singularity is it impossible to find a locally flat reference frame.

        • by Baby Duck (176251)

          The further you zoom out, the flatter everything appears in relation to everything else (globally flat). If you zoom way in, you can find numerous examples of arrangements across all three dimensions (locally non-flat).

          Even if gravity is unlimited and radiates volumetricly, as you zoom out, there is no matter/energy for the gravity along the Z-axis to exert itself upon. And remember, you can still compare infinite sequences. One can state gravity is much stronger along the X-axis and Y-axis than the Z-axis,

  • Terrifying (Score:2, Insightful)

    by gmuslera (3436)
    Odds are pretty high that we will never reach the next star, worrying about the next galaxy is a bit too much
  • by NEDHead (1651195) on Wednesday June 04, 2014 @08:10AM (#47163583)

    Now I'll never find the missing socks

  • At least in astronomy beyond naked-eye observation.

    The universe is so vast that it boggles my mind. Just the distance between star systems in our galaxy is huge, then when you start thinking about the distance between galaxies, and then that there are clusters of galaxies... and the distance between clusters of galaxies. It's too much.

    Not to mention that it pretty much puts the kibosh on things like intergalactic travel, probably even interstellar travel too.

  • We're Doomed. Dooooomed.

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