5 ms·

I have often thought about what it would be like in the far, far future. After the age of baryons comes to an end, we would also see an end to structure: you c

I have often thought about what it would be like in the far, far future. After the age of baryons comes to an end, we would also see an end to structure: you cannot build anything out of leptons larger than a positron and electron orbiting one another, delicately, at a distance. No chains, no three-way bonds or glorious carbon four-way bonds, just a froth of electrons, positrons, and variously-flavred neutrinos and anti-neutrinos. If the Big Rip were to happen, one might imagine civilizations forming around the event horizons of black holes ("dead stars still burn") fizzing out Hawking radiation, getting ever closer to avoid the Big Rip, a controlled fall designed to balance against the stretching of space while harvesting what you could get from Hawking radiation. I've seen projections, sketches, really, of computation that involved states only changing as energy became free, and so these civilizations would be almost frozen in amber to outsiders but ticking along from their vantage point, up until the black holes' "temperature" drops too far below the ambient themal bath. The decay gets faster and faster as the curvature of the event horizon increases, so that civilization's end would have an incredible speedup right before the black hole itself evaporated.

qubex 6y ago
The last bit you mention reminded me a lot of The Physics of Immortality (Frank J. Tipler, 1994) which I first read in when I was thirteen or fourteen years old. This was before it had been proven that the cosmological constant existed and was positive, so he was musing about how a quantum computer instantiated in the final moments of a Big Crunch would have asymptotically infinite processing power and could simulate everybody who ever lived (and everybody who didn’t actually live, but could have, too).
eternauta3k 6y ago
An electron-positron bound system decays in under a nanosecond: https://en.wikipedia.org/wiki/Positronium https://en.wikipedia.org/wiki/Positronium
- at_a_remove 6y ago
  "Delicately."
raattgift 6y ago
> If the Big Rip were to happen That's a really big If. Since we're well into the realm of fields-on-General Relativity in this paragraph, you'd have to add one or more additional fields to provide a "fifth force" (thus, in these sorts of approaches quintessence) to overcome the other known fundamental interactions among the other fields of the Standard Model, of which there are more than three. The fourth, gravitation, is poorly modelled as a force when we are dealing with clearly relativistic gravitation, as is the case with [a] a black hole or [b] the appearance of lots of empty space around all sources of gravitation. Nobody has yet made a consistent interacting model of quintessence, where the interactions reflect those of the Standard Model or gravitation, so nobody can really do anything but handwave about what extra interactions from "fifth force" fields would do with respect to e.g. the Higgs mechanism. Additionally, I say fields because when one gets into the weeds of formalizing a quintessence field theory one ends up with self-interactions -- additional interactions in the new parts added to the Standard Model. Quintessence theories are interesting to probe the structure of theories (mostly quantum field theories in curved spacetime), but are really not interesting for studying the physically observed cosmos with our present level of understanding of the Hubble parameter, or the mechanisms that generate the "true" metric. Without these extra interactions, there is good reason to believe that there won't be a big rip: at smaller scales, stars, planets, people, pocket computers, molecules, atoms, are in no danger of being locally disturbed by the metric expansion of inter-galaxy-cluster space. > around the event horizons of black holes ("dead stars still burn") fizzing out Hawking radiation Hawking radiation appears surprisingly far from the event horizon, rather than near it[1] and for a black hole whose near-horizon exterior is gentle enough an environment to support any sort of structure (space-stations, say, and especially ones that can support life as we know it) the Hawking radiation is virtually always going to be colder than the cosmic microwave background measured in local coordinates by a near-horizon observer. If you want to be fanciful, you are much better off erecting a very large scaffold around a very large black hole, and then "mine" it with a bucket. [2] - -- [1] Unruh [2007], http://inspirehep.net/record/775859?ln=en http://inspirehep.net/record/775859?ln=en from which the DOI link will take you to the cc-by-nc-sa pdf. [2] Brown [2012], PRL preprint https://arxiv.org/abs/1207.3342 https://arxiv.org/abs/1207.3342 has a quick overview and decent bibliography notably Gibbons in [11].
- 6y ago

qubex 6y ago

The last bit you mention reminded me a lot of The Physics of Immortality (Frank J. Tipler, 1994) which I first read in when I was thirteen or fourteen years old. This was before it had been proven that the cosmological constant existed and was positive, so he was musing about how a quantum computer instantiated in the final moments of a Big Crunch would have asymptotically infinite processing power and could simulate everybody who ever lived (and everybody who didn’t actually live, but could have, too).

eternauta3k 6y ago

An electron-positron bound system decays in under a nanosecond: https://en.wikipedia.org/wiki/Positronium https://en.wikipedia.org/wiki/Positronium

at_a_remove 6y ago
"Delicately."

raattgift 6y ago

> If the Big Rip were to happen That's a really big If. Since we're well into the realm of fields-on-General Relativity in this paragraph, you'd have to add one or more additional fields to provide a "fifth force" (thus, in these sorts of approaches quintessence) to overcome the other known fundamental interactions among the other fields of the Standard Model, of which there are more than three. The fourth, gravitation, is poorly modelled as a force when we are dealing with clearly relativistic gravitation, as is the case with [a] a black hole or [b] the appearance of lots of empty space around all sources of gravitation. Nobody has yet made a consistent interacting model of quintessence, where the interactions reflect those of the Standard Model or gravitation, so nobody can really do anything but handwave about what extra interactions from "fifth force" fields would do with respect to e.g. the Higgs mechanism. Additionally, I say fields because when one gets into the weeds of formalizing a quintessence field theory one ends up with self-interactions -- additional interactions in the new parts added to the Standard Model. Quintessence theories are interesting to probe the structure of theories (mostly quantum field theories in curved spacetime), but are really not interesting for studying the physically observed cosmos with our present level of understanding of the Hubble parameter, or the mechanisms that generate the "true" metric. Without these extra interactions, there is good reason to believe that there won't be a big rip: at smaller scales, stars, planets, people, pocket computers, molecules, atoms, are in no danger of being locally disturbed by the metric expansion of inter-galaxy-cluster space. > around the event horizons of black holes ("dead stars still burn") fizzing out Hawking radiation Hawking radiation appears surprisingly far from the event horizon, rather than near it[1] and for a black hole whose near-horizon exterior is gentle enough an environment to support any sort of structure (space-stations, say, and especially ones that can support life as we know it) the Hawking radiation is virtually always going to be colder than the cosmic microwave background measured in local coordinates by a near-horizon observer. If you want to be fanciful, you are much better off erecting a very large scaffold around a very large black hole, and then "mine" it with a bucket. [2] - -- [1] Unruh [2007], http://inspirehep.net/record/775859?ln=en http://inspirehep.net/record/775859?ln=en from which the DOI link will take you to the cc-by-nc-sa pdf. [2] Brown [2012], PRL preprint https://arxiv.org/abs/1207.3342 https://arxiv.org/abs/1207.3342 has a quick overview and decent bibliography notably Gibbons in [11].

6y ago