The following is modified from Wikipedia - The Five Ages of the Universe.
The Five Ages of the Universe, a 1999 science book by Fred Adams and Gregory Laughlin, discusses the history, present state, and probable future of the universe, according to the current understanding of the universe. The book divides the timeline of the universe into five eras: the Primordial Era, the Stelliferous Era, the Degenerate Era, the Black Hole Era and the Dark Era. Here, the time scales are referred to in logarithmic scientific notation, meaning that each stage is ten times longer than the previous.
The Primordial Era is considered at the start of the timeline on the page on Cosmogenesis and the Big Bang, the rest of the timeline and the other pages cover the Stelliferous Era.
The physicist Freeman Dyson has speculated that, all other things being equal, the rate of metabolism—and therefore rate of consciousness—of an organism should be in direct proportion to the temperature at which that organism thrives. The authors envision life forms completely different from the biochemical ones of Earth, for example, based on networked black holes. These may be descendants of the grabby aliens, the most powerful beings or civilisations in the physical universe.
Degenerate Era:. The Degenerate Era is defined as "15 < n < 39". This is the era of brown dwarfs, white dwarfs, neutron stars and black holes. White dwarfs will assimilate dark matter and continue with a nominal energy output. As this era continues, the authors hypothesize that protons will begin to decay (violating the conservation of baryon number given by the Standard Model). If proton decay takes place, the sole survivors will be black holes. If so, life becomes nearly impossible as planets decay.
Black Hole Era:. The Black Hole Era is defined as "40 < n < 100". In this era, according to the book, organized matter will remain only in the form of black holes. Black holes themselves slowly "evaporate" away the matter contained in them, by the quantum mechanical process of Hawking radiation. By the end of this era, only extremely low-energy photons, electrons, positrons, and neutrinos will remain.
Dark Era:. The Dark Era is defined as "n > 101". By this era, with only very diffuse matter remaining, activity in the universe will have tailed off dramatically, with very low energy levels and very large time scales. Electrons and positrons drifting through space will encounter one another and occasionally form positronium atoms. These structures are unstable, however, and their constituent particles must eventually annihilate. Other low-level annihilation events will also take place, albeit very slowly. Essentially, the universe will eventually turn into a void.
Page by M Alan Kazlev, 2023