"In the beginning, just after the big bang event, the universe was too hot and energetic to contain any stellar bodies. All the matter content of the universe was in the form of individual particles. This time before the dawn of stars is sometimes called the Primordial Era, and is described in the previous chapters. This era begins at an age of about 10^ -43 s – the smallest slice of time that can be defined because of quantum gravity – and ends when the first structures condense out of the expanding universe. No structure can be formed until the radiation has decoupled from the matter, and this transition takes place when the cosmic age is about 300,000 years. The first stars are formed somewhat later, perhaps when the universe is one million years old, or shortly thereafter.
After the stars have burned out, the remnants they leave behind will be the primary stellar bodies in the universe. These entities include brown dwarfs, white dwarfs, neutron stars, and black holes. Since the first three types of remnants are supported by quantum mechanical degeneracy pressure, this future epoch is often called the Degenerate Era. During this future time period, the universe remains active: white dwarfs capture Dark Matter particles, brown dwarfs collide to make new stars, white dwarfs collide to ignite supernovae, galactic disks evaporate, and the Dark Matter halos eventually annihilate. This era draws to a close when the universe becomes old enough for protons to decay, at a future epoch more than 10^33 years from now. All of the degenerate stellar remnants lose their mass through proton decay and eventually fade into nothingness.
Black holes are the only stellar objects that survive the dilapidation enforced by proton decay, and they inherit the universe during the subsequent Black Hole Era. In the darkness of this future epoch, the radiation produced by black holes through the Hawking mechanism powers the universe. As the black holes shine, they also lose mass, and must eventually evaporate. The largest black holes live the longest. But after 10^100 years, all of them will have made their explosive exits, and the universe changes its character once again.
After the black holes are gone, no stellar objects of any kind are left to light up the skies. Only the leftover waste products from the previous eras remain, and the universe slides into its Dark Era. The cosmic inventory is now extremely sparse, containing electrons, positrons, neutrinos, Dark Matter particles, and photons of stupendously long wavelengths. In the Primordial Era, the universe contained no stars – only particles – because it was too hot and too young. In the Dark Era in our distant future, the universe again has no stars – and only particles – because it is too cold and too old. These endpoints frame the story of our universe: Instead of evolving from ashes to ashes, or dust to dust, the cosmic timeline runs from particles to particles."
Adams, F. C. (2012). Future History of the Universe. In F. Adams, T. Buchert, & L. Mersini-Houghton (Eds.). Cosmic Update: Dark Puzzles. Arrow of Time. Future History. (Multiversal Journeys). Springer.
After the stars have burned out, the remnants they leave behind will be the primary stellar bodies in the universe. These entities include brown dwarfs, white dwarfs, neutron stars, and black holes. Since the first three types of remnants are supported by quantum mechanical degeneracy pressure, this future epoch is often called the Degenerate Era. During this future time period, the universe remains active: white dwarfs capture Dark Matter particles, brown dwarfs collide to make new stars, white dwarfs collide to ignite supernovae, galactic disks evaporate, and the Dark Matter halos eventually annihilate. This era draws to a close when the universe becomes old enough for protons to decay, at a future epoch more than 10^33 years from now. All of the degenerate stellar remnants lose their mass through proton decay and eventually fade into nothingness.
Black holes are the only stellar objects that survive the dilapidation enforced by proton decay, and they inherit the universe during the subsequent Black Hole Era. In the darkness of this future epoch, the radiation produced by black holes through the Hawking mechanism powers the universe. As the black holes shine, they also lose mass, and must eventually evaporate. The largest black holes live the longest. But after 10^100 years, all of them will have made their explosive exits, and the universe changes its character once again.
After the black holes are gone, no stellar objects of any kind are left to light up the skies. Only the leftover waste products from the previous eras remain, and the universe slides into its Dark Era. The cosmic inventory is now extremely sparse, containing electrons, positrons, neutrinos, Dark Matter particles, and photons of stupendously long wavelengths. In the Primordial Era, the universe contained no stars – only particles – because it was too hot and too young. In the Dark Era in our distant future, the universe again has no stars – and only particles – because it is too cold and too old. These endpoints frame the story of our universe: Instead of evolving from ashes to ashes, or dust to dust, the cosmic timeline runs from particles to particles."
Adams, F. C. (2012). Future History of the Universe. In F. Adams, T. Buchert, & L. Mersini-Houghton (Eds.). Cosmic Update: Dark Puzzles. Arrow of Time. Future History. (Multiversal Journeys). Springer.