The History and Fate of the Universe
Degenerate Era
t = 16 : colliding brown dwarfs
t = 19 : most brown dwarfs, planets
ejected
t = 30 : remaining dwarfs fall into
central black hole
t = 37 : free protons decay, neutron
stars decay
t = 39 : protons in dwarfs and
planets decay
Black Hole Era
t = 42 : dark matter particles decay
into photons
t = 66 : stellar black holes
evaporate
t = 84 : galactic black holes
evaporate
t = 98 : cluster black holes
evaporate
t = 141 : last positronium decays
(see “The Five Ages of the
Universe” by Adams and Laughlin)
Define time by “cosmic decade”: time=10 t years
(t is
decade)
