I found How Will the Universe End? fascinating and hilarious and oddly comforting:
It was time to tally up the eschatological results. The cosmos has three possible fates: Big Crunch (eventual collapse), Big Chill (expansion forever at a steady rate), or Big Crackup (expansion forever at an accelerating rate). Humanity, too, has three possible fates: eternal flourishing, endless stagnation, or ultimate extinction. And judging from all the distinguished cosmologists who weighed in with opinions, every combination from Column A and Column B was theoretically open. We could flourish eternally in virtual reality at the Big Crunch or as expanding black clouds in the Big Chill. We could escape the Big Crunch/Chill/Crackup by wormholing our way into a fresh universe. We could face ultimate extinction by being incinerated by the Big Crunch or by being isolated and choked off by the Big Crackup. We could be doomed to endless stagnationâ€”thinking the same patterns of thoughts over and over again, or perhaps sleeping forever because of a faulty alarm clockâ€”in the Big Chill. One distinguished physicist I spoke to, Andrei Linde of Stanford University, even said that we could not rule out the possibility of their being something after the Big Crunch. For all of the fascinating theories and scenarios they spin out, practitioners of cosmic eschatology are in a position very much like that of Hollywood studio heads: Nobody knows anything.
Still, little Alvy Singer is in good company in being soul-sick over the fate of the cosmos, however vaguely it is descried. At the end of the 19th century, figures like Swinburne and Henry Adams expressed similar anguish at what then seemed to be the certain heat-death of the universe from entropy. In 1903 Bertrand Russell described his “unyielding despair” at the thought that “all the labors of the ages, all the devotion, all the inspiration, all the noonday brightness of human genius, are destined to extinction in the vast death of the solar system, and that the whole temple of Man’s achievement must inevitably be buried beneath the debris of a universe in ruins.” Yet a few decades later, he declared such effusions of cosmic angst to be “nonsense,” perhaps an effect of “bad digestion.”
Why should we want the universe to last forever, anyway? Lookâ€”either the universe has a purpose or it doesn’t. If it doesn’t, then it is absurd. If it does have a purpose, then there are two possibilities: Either this purpose is eventually achieved, or it is never achieved. If it is never achieved, then the universe is futile. But if it is eventually achieved, then any further existence of the universe is pointless. So, no matter how you slice it, an eternal universe is either a) absurd, b) futile, or c) eventually pointless.