The Five Ages of the Universe

Infobox Book |
name = The Five Ages of the Universe: Inside the Physics of Eternity


image_caption = Cover
author = Fred Adams and Gregory Laughlin
country =
language = English
genre = popular science
publisher = Free Press Publishers
release_date = 1999
media_type =
pages = 251
isbn = ISBN 978-0684865768

"The Five Ages Of The Universe" is a popular science book written by Professor Fred Adams and Gregory Laughlin [cite web |url=http://www.ucolick.org/~laugh/homepage.html |title=Gregory Laughlin] first published in 1999. [cite news |url=http://www.nytimes.com/books/first/a/adams-universe.html |title=Book review |publisher=New York Times]

Book contents

The book "The Five Ages of the Universe" discusses the history, present state, and probable future of the universe, according to cosmologists' current understanding. 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.

In addition to explaining current cosmological theory, the authors speculate on what kinds of life might exist in future eras of the universe. The speculation is based on a scaling hypothesis, due to Freeman Dyson, the idea being 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.

The Five Ages

The time scales treated in the book are sufficiently vast that the authors find it convenient to use scientific notation. They refer to the "n^th cosmological decade," meaning 10ⁿ years after the big bang. In what follows, n refers to the cosmological decade.

Primordial Era -50 < n < 5

In this era, the Big Bang, the subsequent inflation, and Big Bang nucleosynthesis are thought to have taken place. Toward the end of this age, the recombination of electrons with nuclei made the universe transparent for the first time. The authors discuss the horizon and flatness problems.

Stelliferous Era 6 < n < 14

This is the current era, in which matter is arranged in the form of stars, galaxies, and galaxy clusters, and most energy is produced in stars. Massive stars use up their fuel very rapidly, in as little as a few million years. Eventually, the only stars will be miserly red dwarf stars. By the end of this era, bright stars as we know them will be gone, their nuclear fuel exhausted, and only white dwarfs, brown dwarfs, and black holes will remain. In this section, Olbers paradox is discussed.

Degenerate Era 15 < n < 39

This is the era of brown dwarfs, white dwarfs, 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.

Black Hole Era 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 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.

References

External links

* [http://www.physics.lsa.umich.edu/department/directory/bio.asp?ID=1 Web page of Fred Adams]
* [http://archive.ala.org/booklist/v95/adult/ap2/16adams.html Booklist Magazine summary]