Even though the universe is only 13.8 billion years old, more or less, the era of star formation is nearly complete. Because our universe expands so rapidly, the effects of gravity continue to lessen and therefore matter will soon cease to clump. Existing stars and galaxies will become more and more isolated. In a hundred billion years, the universe will be a thousand times larger than it is now. After a trillion years, all the stars will have burnt themselves out, except for slow-burning, feeble red dwarfs. In a hundred trillion years the Degenerate Era arrives and the universe will be populated only by white dwarfs and brown dwarfs, along with neutron stars and black holes, all fainter and fainter with time. It will all be dark, except when a rare supernova erupts. After 1034 years, atoms themselves will decay into protons and neutrons. In 1040 years, all of what we think of as matter will have become photons and leptons. Later, black holes themselves will leak photons and disappear. It's the Dark Era: just random electrons and positrons that rarely encounter each other -- an inactive universe that suffers from Heat Death. It's all dark, dead, and cold. This sorry state will continue for all eternity.
it's a gloomy scenario, but I don't believe it. It doesn't make sense. And it doesn't account for Dark Matter and Dark Energy, which no one knows anything about except that they must exist perhaps in the form of neutrinos. Most physicists seem to believe that the visible, palpable universe, which contains the galaxies and the stars and the planets and you and me, is only about 6% of the whole kit and kaboodle.
My own theory, unsupported by observation, evidence, or calculation, is that the universe will continue to expand for billions of years, and then Dark Matter will kick in, gravity will plump up and spring to new life, and the universe will start to contract. A few thousand billion years further on and here comes the Big Crunch, when all matter will contract to a point and then, mirabile dictu, another Big Bang and it's off to the races. Expand. Wait a few thousand trillion years. Contract. More years -- expand. Contract. Expand. Again and again. My universe pulses, for all eternity. Et saecula saeculorum; in aeternum et ultra. No beginning, no end.
The scientific consensus universe is this: start with the Big Bang, end with the eternal Dark Era. It's one-way ticket. My universe is round-trip. Multiple, infinite round-trips. The astronomers have the data and the numbers and theory on their side, but they can't explain how it all happened, or why? Why the Big Bang? What was going on before all the Banging began? They don't have a glimmer of an idea, not a clue; in fact, they punt and claim that it's impossible to know what happened in the first few fractions of seconds. But my universe has no start and no stop. It just is.
Neither their theory nor mine answers the implicit question, which some might call philosophical or theological: "why is there something rather than nothing?" But my idea has the advantage in that it defers that question indefinitely. "What happened at the Big Bang? "Well, what happened is what always happens at Big Bangs."
(Information about the end of the universe is adapted from David J. Eicher, The New Cosmos (Cambridge University Press, 2015), an excellent introduction that is written so lucidly that I understood maybe 60% to 70% of the whole. Well, perhaps a little less. It's not Eicher's fault if I've gotten anything wrong.)
The possibility of an oscillating universe makes me preach to my colleagues not to negotiate in the next 1980 a contract that lowers everyone's pay (my teachers' union actually did that) and not to vote Republican in the next 2016 election. We all need second chances. Check that: we all need another chance to get it right. Who knows if it will be the second?
Jim Holt's book on this subject, "Why Does the World Exist?" discusses how some of the greatest minds on this earth have grappled with this question: Roger Penrose, Adolf Grunbaum, Steven Weinberg, even John Updike, who explored it in "Roger's Version," to name a few.
Of course, even if there is a Big Crunch, it does seem clear that everything will be completely different, and that reality will be comprised of life forms we cannot even imagine in those Crunch-created universes capable of sustaining life. The trillions and trillions of particles that make us who we are are not likely to find each other and be reassembled.
Holt concludes his chapter on Weinberg by quoting Weinberg's conclusion to "The First Three Minutes": "The effort to understand the universe is one of the very few things that lifts human life above the level of farce, and gives it some of the grace of tragedy." Noble words, but I still find myself drawn to one of Woody Allen's takes on death: "I don't mind dying. I just don't want to be there when it happens."
Posted by: Don Z. Block | August 26, 2020 at 04:09 AM