The Five Ages of the Universe: Inside the Physics of Eternity - Hardcover

Greg Laughlin; Fred Adams

Hardcover

ISBN 10: 0684854228 ISBN 13: 9780684854229

Publisher: Free Press, 1999

Synopsis

Two astrophysicists offer a chronicle of the universe's history, describing its beginning with the Big Bang and looking into the incredibly distant future, with vivid portraits of the sun's death, the evaporation of black holes, and other astronomical end-time events

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Reviews

Imagine peering into a crystal ball and watching the laws of nature run their course through all of time and all of space. What exactly would you see? One thing is for sure, the cosmos is destined to expand forever. Regardless of what you may occasionally hear on the street or read in the newspapers, the idea that the universe will one day recollapse has never been supported by reliable data. We've made the observations. We've done the arithmetic. When you add up all the mass contained in the hundred billion galaxies scattered from here to the limits of our most powerful telescopes--the ubiquitous dark matter included--you do not have enough gravity to halt our current state of expansion. Worse yet, recent evidence that compared the observed brightness of distant supernovae with their predicted brightness suggests that the expansion of the universe may actually be accelerating. This one-way cosmos in which we live may not be philosophically satisfying, but to Fred Adams and Greg Laughlin, co-authors of The Five Ages of the Universe, it's a theorist's amusement park. Armed with just the few basic laws of physics and an understanding of the astrophysical behavior of cosmic objects, the authors ride the universe into a formerly unimaginable future. Making the necessary assumption that our knowledge of the laws of physics is accurate and complete, they ask a simple question of their crystal ball: What is the long-term evolutionary fate of all objects in our eternally expanding universe, from its subatomic particles to entire galaxies? Their answer takes the reader so far into the future that the ordinary reckoning of time swiftly loses its utility. So they use a sensible new clock wherein each tick h (the Greek letter eta) is a cosmological "decade" that lasts 10 times longer than the previous tick. In other words, they reckon time by the exponent when years are measured as a power of 10. A logarithmic timescale is entirely appropriate because the pace of events slows down over time: unimaginably brief intervals in the early universe saw as much astrophysical action as stretches of billions of years do today. Having anointed themselves with powers of hindsight and foresight, the authors move from the big bang to the indefinite future, characterizing the universe along the way by five basic time periods. First comes the primordial era (-50 < n < 5), followed by the stellar era (6 < n < 14). Next is the degenerate era (15 < n < 39), in which the authors assure us that the name refers to a dense quantum state of bulk matter rather than a state of moral turpitude. The black hole era (40 < n < 100) follows, and of course they end with the dark era (n > 101). For reference, the current 15-billion-year age of the universe can be written as 1.5 x 1010 years and falls just above n = 10. Yes, we live in the stellar era, where the energy generated within the universe is dominated by starlight. The stellar era also happens to be when all our laws of physics were discovered and tested, so this part of the book will certainly have the longest shelf life. The contents of both the primordial and stellar eras may ring familiar to avid readers of popular literature on astronomy, but the treatment nonetheless represents a compact, if occasionally dry, review of modern astrophysics. Decay and Degeneration At the dawn of the degenerate era, all gas clouds have been used up to make stars. All stars, even the "long-lived," low-mass ones, have exhausted their thermonuclear fuel. All that's left is the trinity of degenerate stellar corpses: white dwarfs, neutron stars and black holes. By the middle of the degenerate era, a single cosmic decade lasts 25 powers of 10 longer than the current age of our universe. Predictions get more and more speculative and more and more fun, because events that were formerly improbable in one decade now become highly likely in another decade. In the stellar era, stars hardly ever journeyed near enough to one another for their gravity to make a substantial difference in their orbital paths, even during head-on collisions of entire galaxies--stars are very small when compared with the distances that separate them. The stars (rather, their corpses) now have close encounters almost continuously and thus undergo "dynamical relaxation," in which low-mass objects are thrust out of the system while high-mass stars descend toward the galaxy center. While some corpses are cast adrift in the cosmos, the rest of them are eaten whole by the supermassive black holes that lurk in the galactic centers. We have entered the black hole era, where nearly all cosmic energy is now traceable to Hawking radiation as the black holes of the universe evaporate away. When all black holes have disappeared, and there are no sources of fresh energy left, we have entered the dark ages: the temperature of the entire universe asymptotically approaches absolute zero. Only then will the cosmos be dead, by any measure of the word. The authors' journey through time continuously engages the imagination as they take the known laws of physics right up to their natural limits. In this intellectual venue, speculation can be justly accused of becoming wishful thinking. Yet sometimes wishes come true. Cosmologists have been describing the early universe ever since physicist George Gamow, in the 1940s, turned the clocks back and predicted the existence of remnant energy from the big bang--the cosmic microwave background radiation. And today, for example, grand unification theories in physics predict that the proton is unstable and will eventually decay in 1030 years--a factor of a quintillion longer than the current age of the universe. Experiments are now being designed to see this happen. Naturally, proton decay factors significantly into the happenings of the degenerate era, as the authors are granted plenty of time to kill every proton in every nucleus of every atom in the entire universe. In The Five Ages of the Universe, Adams, who teaches physics at the University of Michigan, and Laughlin, a postdoctoral fellow at the University of California at Berkeley, deftly invoke all known laws of the universe to spin an entertainingly scary picture of our distant future. During our eternal cosmic expansion, if new laws of physics are revealed, then many (if not most) of their predictions will fail. They admit this obvious shortcoming. But I don't mind, because I enjoyed the journey. When new laws of physics demand it, I will simply ask them to weave an updated scientific tale that takes me back to the future once more.

Eternity is a daunting concept, but modern cosmologists are not afraid to face it. Cosmology usually concentrates on the beginnings of the universe, but what might happen at the other end of time is just as intriguingand by far the greater portion of the story. Adams and Laughlin, two leading astrophysicists (at the University of Michigan and the University of California, Berkeley, respectively) divide the life span of the universe into five acts, beginning with the Primordial Era, the time of the Big Bang and its immediate aftermath, when hydrogen and helium were first formed in an explosive birth. The Stelliferous Era is our present period, when stars fill the universe with visible light. The authors expect this to last another 100 trillion years. The universe doesnt end with the fading of the visible stars, but enters a time dominated by lesser lights: brown dwarfs, white dwarfs, and other stellar remnants. This is the Degenerate Era, when the primary source of cosmic energy is proton decay, slow and feeble: a typical degenerate star might achieve the brightness of half a dozen ordinary light bulbs. An occasional stellar collision may light up the sky with a supernova. After all protons decay, the universe will enter its fourth act: the Black Hole Era. Black holes' enormous gravity protects them from losing mass and energy by ordinary processes, but they slowly dissipate through Hawking radiation and will become extinct after ten-to-the-hundredth-power years. This leaves only the most tenuous forms of matter and energy to fill out the Dark Era: electrons, neutrinos, and low-energy photons that interact only sporadically. The authors fill in this broad outline in fascinating detail, considering such questions as the long-term prospects for life and the possibility of recollapse to a singularity (a ``Big Crunch'') rather than a slow dying out of the fire. A thought-provoking treatment of the grandest of subjects, highly recommended to anyone interested in the world beyond tomorrow. -- Copyright ©1999, Kirkus Associates, LP. All rights reserved.

Piling one layer of speculation upon another yet retaining a disciplined, scientific approach, astrophysicists Adams (University of Michigan) and Laughlin (UC-Berkeley) take readers on a cosmic adventure to a time in the unimaginably distant future. They view time not in linear years but in logarithmic cosmological decades. We live early in the 10th cosmological decade, approximately 10 billion (10 to the 10th power) years since the Big Bang. For the first six cosmological decades, the Primordial Era, the authors explain, an intensely hot universe expanded and cooled. Elementary particles formed, followed by atoms and molecules. The stage was set for the present Stelliferous Era of galaxies, stars and planets that will continue through the 14th cosmological decade. Our universe will then be 10,000 times its present age, and even its slowest-burning stars will have used up their nuclear fuel. Stellar remnants will dominate the next 25 cosmological decades, the Degenerate Era. Following that will be the Black Hole Era, more than 60 cosmological decades long. The final chapter will be the Dark Era, a steadily diminishing, infinitely long decline toward universal equilibrium. The authors speculate on the survival of intelligent life through the entire history. They also discuss the evolution of universes in Darwinian terms. Many readers will reach their saturation point for conjecture well before those final sections, but others, especially science fiction buffs, will savor every lengthening, darkening, diminishing epoch leading to the authors' concluding vision: the birth of new universes more than 100 cosmological decades after ours burst into existence. (June)
Copyright 1999 Reed Business Information, Inc.

In order to tell the story of the universe from its origin to its ultimate demise, the authors (both well-known astrophysicists) have divided all of time into five eras. The first, the Primordial Era, begins with the big bang and the eventual synthesis of hydrogen that makes stars. The Stelliferious Era (meaning filled with stars) began just a few billion years ago, and we are currently in the middle of this era of bright stars and galaxies. The third era sees the diminution of the bright stars and the ascendance of white and brown dwarfs, neutron stars, and black holes. Black holes in fact become the only objects in the next era, naturally titled the Black Hole Era. Eventually, even the black holes evaporate, and the final Dark Era arrives, a time in which there are no stellar objects of any kind. Good illustrations help explain complex concepts, and the glossary is useful. This unusual history of the universe is accessible to the educated general reader and recommended for academic and large public libraries.James Olson, Northeastern Illinois Univ. Lib., Chicago
Copyright 1999 Reed Business Information, Inc.

The question in cosmology is whether the universe will stop expanding. Physicists Adams and Laughlin are not banking on it. The appearance of a universe forever expanding is literally not bright, but since eternity provides the time, theory allows strangely interesting occurrences until an unimaginably distant Dark Era is reached. Of the other eras by which the authors arrange this fantastic, fascinating book, we live in the Stelliferous Era, dominated by stars in galaxies. The past was the Primordial Era, whose central event was the big bang; future auguries point toward a Degenerate Era, in which burnt-out remnants of stars sputter to their ends through proton decay, leaving the black holes to soldier on into their eponymous era, about ten billion quadrillion years from now. The omens for this ultimate Grim Reaper story lie in cosmologists' technical papers. Digesting that material and tossing in their own doomsday scenarios, for example, the Earth's ejection from the solar system by an intruding star, the authors effectively impress on interested nonscientists the implications of the universe's colossal time dimension. A stellar piece of science popularization. Gilbert Taylor

Edition details

• Publisher: Free Press
• Publication date: 1999
• Language: English
• ISBN 10: 0684854228
• ISBN 13: 9780684854229
• Binding: Hardcover
• Edition number: 1
• Number of pages: 288