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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.
(Score: 2) by Immerman on Friday June 22 2018, @05:40PM (1 child)
How are you going to produce the antimatter? After all, it's an energy storage medium, not a source. You need an even larger energy source to create it. And if you're talking about the sorts of timescales where cosmic expansion is relevant... well then you're going to need more stars once your own has burnt out, and all the others will have been carried out of reach, or even sight, with the space between them expanding faster than lightspeed.
Though, my understanding is that the current prevailing belief is that cosmic expansion won't tear apart galaxies - they're simply too small and tightly-bound by gravity. Galactic clusters may well be scattered, but a civilization that needs a galactic cluster worth of available stars to survive... well, that's well beyond Kardashev Type III (which have harnessed their host galaxies total energy output), and you'd need to move entire galaxies around to do it. Moving individual stars as a major endeavor is more characteristic of a class II civilization. Heck, even a class 1 (1.5?) civilization might find it feasible - you probably don't need to harness anything like the entire output of a star to be able to trigger timed solar flares to act as a rocket engine.
(Score: 2) by VLM on Friday June 22 2018, @07:46PM
Well thats easy, you take the year 2999 equivalent of an Arduino and tell the self replicating nano-assemblers, probably in fucking Java, to self replicate into bigger self replicators that build large nano assemblers that eat abundant solar energy and turn that energy and trace elements into gigantic planetary ring size solar collectors powering equally large antimatter generating machines (we have those today, they're big and expensive but neither matter if you own nanoassembers that can turn anything into whatever you want, given enough sunlight, which you also have "infinite" amounts of). Then a long electromagnetic catapult starts tossing starships back home with holds full of stored antimatter, and centuries later they arrive. All begun by launching a little pillbox size bottle of programmed nanoassembers.
This is a fairly likely hard sci fi "interplanetary duel" scenario. The way we meet the Romulan Star Empire is they thought sol was empty (or maybe knew we populate it?) and they will try to turn the solar system into a giant solar battery charger using nanoassembers, essentially. Interesting thought experiment as a book plot... life on earth outcompetes and merges with aspects of the nanoassembers so everything on earth remains alive, but ... warped, while entire rest of the solar system is turned into giant solar battery chargers for "the enemy". Damn good thing Trump formed the Space Marines last week because they're gonna have their hands full figuring this one out.