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posted by martyb on Friday June 22 2018, @02:25AM   Printer-friendly
from the star-wars:-where-combatants-toss-stars-at-each-other dept.

How an Advanced Civilization Could Stop Dark Energy From Preventing Their Future Exploration

For the sake of his study, which recently appeared online under the title "Life Versus Dark Energy: How An Advanced Civilization Could Resist the Accelerating Expansion of the Universe", Dr. Dan Hooper considered how civilizations might be able to reverse the process of cosmic expansion. In addition, he suggests ways in which humanity might looks[sic] for signs of such a civilization.

[...] This harvesting, according to Dr. Hooper, would consist of building unconventional Dyson Spheres that would use the energy they collected from stars to propel them towards the center of the species' civilization. High-mass stars are likely to evolve beyond the main sequence before reaching the destination of the central civilization and low-mass stars would not generate enough energy (and therefore acceleration) to avoid falling beyond the horizon.

For these reasons, Dr. Hooper concludes that stars with masses of between 0.2 and 1 Solar Masses will be the most attractive targets for harvesting. In other words, stars that are like our Sun (G-type, or yellow dwarf), orange dwarfs (K-type), and some M-type (red dwarf) stars would all be suitable for a Type III civilization's purposes.

[...] Based on the assumption that such a civilization could travel at 1 – 10% the speed of light, Dr. Hooper estimates that they would be able to harvest stars out to a co-moving radius of approximately 20 to 50 Megaparsecs (about 65.2 million to 163 million light-years). Depending on their age, 1 to 5 billion years, they would be able to harvest stars within a range of 1 to 4 Megaparsecs (3.3 million to 13 million light-years) or up to several tens of Megaparsecs.

In addition to providing a framework for how a sufficiently-advanced civilization could survive cosmic acceleration, Dr. Hooper's paper also provides new possibilities in the search for extra-terrestrial intelligence (SETI). While his study primarily addresses the possibility that such a mega-civilization will emerge in the future (perhaps it will even be our own), he also acknowledges the possibility that one could already exist.

Kardashev scale. One parsec is equivalent to a distance of approximately 3.26156 light years. Corrections made above.


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  • (Score: 5, Informative) by Immerman on Friday June 22 2018, @03:10AM (5 children)

    by Immerman (3985) on Friday June 22 2018, @03:10AM (#696573)

    Okay - you've got a fusion reactor - where are you getting your fuel? Suck dry a gas giant? That won't last long - gas giants are tiny - you'll burn it all off LONG before the star it's orbiting. The sun is 99.9% of the mass of our solar system - about 1000x more massive than Jupiter. Stars are *the* fusion fuel source in the universe. Near-pure hydrogen stored in gravitational containment reactor of its own making. All other conjectured energy sources combined don't even amount to a drop in the bucket in comparison. (with the possible exception of the wildly hypothetical zero-point energy source)

    Far better to simply encapsulate a red dwarf - they should last trillions of years, far outliving pretty much everything else seen in the universe, and continue outputting star-scale power the entire time. Orders of magnitude less than a larger star, but vastly more than trying to ration the hydrogen in Jupiter across those same trillions of years.

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  • (Score: 4, Interesting) by urza9814 on Friday June 22 2018, @08:06PM (3 children)

    by urza9814 (3954) on Friday June 22 2018, @08:06PM (#696925) Journal

    Far better to simply encapsulate a red dwarf - they should last trillions of years, far outliving pretty much everything else seen in the universe, and continue outputting star-scale power the entire time. Orders of magnitude less than a larger star, but vastly more than trying to ration the hydrogen in Jupiter across those same trillions of years.

    You can apparently suck energy out of the rotation of black holes for many orders of magnitude longer than any star. At best, a star might last a few trillion years...but a black hole could be around for 10^100 years. If you can simulate your biology on a computer, then you can slow down that simulation in order to use less power...and if you're using black holes you can slow it down a hell of a lot and still have a longer lifespan than the entire current age of the universe. Plus that keeps everything very cold which lets you compute more efficiently. The main problem with this seems to be that if you start it now, you might get killed off by some other creature that's living much faster using more traditional power sources. So you'd probably want to at least keep some AI agents "awake" around the nearest star systems. But that still seems simpler than trying to literally move the universe...and it would last a lot longer too.

    • (Score: 2) by Immerman on Friday June 22 2018, @08:37PM (2 children)

      by Immerman (3985) on Friday June 22 2018, @08:37PM (#696946)

      Sure, but the energy levels are going to be miniscule in comparison, at least for a similar mass. Though I suppose you could hang out around the galactic core once all the stars burn out. Or you could rip apart stars into sub-critical masses and use the hydrogen to trickle-feed your primary star (or other fusion generators) as needed. And then feed the resulting dead star to the black hole in such a way as to capture a significant portion of the mass-energy as it annihilates near the event horizon.

      • (Score: 2) by takyon on Friday June 22 2018, @09:24PM (1 child)

        by takyon (881) <reversethis-{gro ... s} {ta} {noykat}> on Friday June 22 2018, @09:24PM (#696976) Journal

        The goal of all civilizations may be to move themselves into a lower energy consumption state, such as uploaded minds.

        Or if we get spooky/magical, ascend like in Stargate SG-1.

        --
        [SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
        • (Score: 2) by Immerman on Friday June 22 2018, @11:27PM

          by Immerman (3985) on Friday June 22 2018, @11:27PM (#697021)

          That's possible - especially as the heat death of the universe looms. Of course lowering your needs means every erg of stockpiled energy will translate into that much greater of a span of continued existence. So it doesn't necessarily translate into a lowered incentive to stockpile stars, and may even do the opposite.

  • (Score: 1) by khallow on Saturday June 23 2018, @02:06AM

    by khallow (3766) Subscriber Badge on Saturday June 23 2018, @02:06AM (#697078) Journal

    All other conjectured energy sources combined don't even amount to a drop in the bucket in comparison.

    Gravitational energy. Dropping matter into a black can theoretically release a significant portion of its mass as usable energy. That includes matter which has already formed another black hole. Even fusion doesn't break 10% mass-energy conversion.