From: Richard Howard <rich@richardehoward.com> Date: 1/10/19, 5:16 PM

A cold, slow universe is an interesting concept.

Everyone should know or remember Freeman Dyson's lecture series / paper, "TIME WITHOUT END: PHYSICS AND BIOLOGY IN AN OPEN UNIVERSE" from 1979. https://www.aleph.se/Trans/Global/Omega/dyson.txt http://scilib-physics.narod.ru/Dyson/dyson.pdf I shall discuss three principal questions within the framework of the open universe with the metric (6). (1) Does the universe freeze into a state of permanent physical quiescence as it expands and cools? (2) Is it possible for life and intelligence to survive indefinitely? (3) Is it possible to maintain communication and transmit information across the constantly expanding distances between galaxies? Skimming just now, I remember bits that made me jump the first time. I'll switch to all quotes: T = 10^65 yr. (36) Even the most rigid materials cannot preserve their shapes or their chemical structures for times long compared with (36). On a time scale of 10^65 yr, every piece of rock behaves like a liquid, flowing into a spherical shape under the influence of gravity. Its atoms and molecules will be ceaselessly diffusing around like the molecules in a drop of water. --- For two nuclei combining to form iron, Z = 26, A = 56, S = 3500, and T = 10^1500 yr. (41) On the time scale (41), ordinary matter is radioactive and is constantly generating nuclear energy. --- The lifetime is then by (30) T = exp(120N^(4/3))T_0. (46) For a typical low-mass star we have N = 10^56, S = 10^77, T = 10^(10^76) yr. (47) In (46) it is completely immaterial whether T_0 [sw: the start time] is a small fraction of a second or a large number of years. We do not know whether every collapse of an iron star into a neutron star will produce a supernova explosion. At the very least, it will produce a huge outburst of energy in the form of neutrinos and a modest burst of energy in the form of x rays and visible light. The universe will still be producing occasional fireworks after times as long as (47). --- TABLE I. Summary of time scales. Closed Universe Total duration 10^11 yr Open Universe Low-mass stars cool off 10^14 yr Planets detached from stars 10^15 yr Stars detached from galaxies 10^19 yr Decay of orbits by gravitational radiation 10^20 yr Decay of black holes by Hawking process 10^64 yr Matter liquid at zero temperature 10^65 yr All matter decays to iron 10^1500 yr Collapse of ordinary matter to black hole [alternative (ii)] 10^(10^26) yr Collapse of stars to neutron stars or black holes [alternative (iv)] 10^(10^76) yr --Steve