Ultimate Fate of Open, Flat and Very Large Closed Universes

Adapted from table 10.2 in Barrow & Tipler's "The Anthropic Cosmological Principle" (ISBN 0-19-282147-4)

Event Timescale (years)
Sun leaves Main Sequence 5 * 10^9
Large clusters evaporate galaxies 10^11
Stars cease to form; all massive stars have become either neutron stars or black holes 10^12
Longest lived stars use all their fuel and become white dwarfs 10^14
Dead planets detached from dead stars by stellar collisions 10^15
White dwarfs cool to black dwarfs at 5° Kelvin (Proton decay will keep dwarfs at this temperature for 10^30 years) 10^17
Dead stars (black dwarfs and neutron stars) evaporate from galaxies (approx 90-99% will evaporate; 1-10% will collect in galactic centres to form gigantic black holes) 10^19
Neutron stars cool to 100° K 10^19
Orbits of remaining planets decay by gravitational radiation 10^20
Dead stars evaporate from galactic clusters (black dwarfs are at 5° K and neutron stars at 100° K due to proton decay; background radiation has cooled to 10^-13° K) 10^23
At this stage matter consists of about 90% dead stars, 9% black holes, and 1% atomic hydrogen and helium
Protons decay (according to SU(5) GUT) 10^31
Dead stars evaporate by proton decay (GUT) 10^32
All carbon-based life-forms become extinct 10^34
At this stage most matter in the Universe is in the form of e+, e-, /v, v and gamma
Ordinary matter liquifies due to quantum tunneling 10^65
Solar mass black holes evaporate by Hawking process 10^66
In flat and closed universes, most e+ and e- form positronium; in open universes, most e+ and e- remain free 10^73
Galactic-mass black holes (10^11 solar masses) evaporate by Hawking process 10^99
In flat and closed universes, positronium decays via cascade, releasing 10^22 photons 10^117
Supercluster-mass black holes (10^17 solar masses) evaporate by Hawking process 10^117
Protons decay by Hawking process 10^122
If ordinary matter survives decay via GUTs or Hawking process, it decays to iron 10^1500
All iron collapses into black holes 10^(10^26)

(After this things begin to look a little bleak).