Tag Archives: ultimate fate of the universe

Citation(s) Needed: Expiration Dates

This is the second issue of my short-lived run as a science writer for my high school newspaper. I think it’s an improvement over the first one. It flows a bit better, has a little more detail, and I tried to inject a little more humor (or at least, snark). It’s definitely a bit weak compared to what came after, though. It’s a bit all over the place and doesn’t have a unifying theme or original thesis to tie it together and justify its existence. – Baeo Maltinsky

The world is ending! Y’know, eventually. I mean, it’s probably ending, right?  The matter of the ultimate fate of the universe is the domain of cosmology. As a field dominated by confusing jargon, untestable predictions, and hand-wavey black boxes, cosmology hasn’t come to a consensus about just what’s going to happen, but here are a few possible outcomes.

The first idea has its roots in 19th century thermodynamics. According to the second law, entropy in the universe is bound to increase. On net, the universe will become less capable of doing useful work as it approaches complete thermodynamic equilibrium. Star formation will cease, and life will become impossible. Supposedly stable atoms like protium decay over such  long periods. Atoms just don’t last forever. Even black holes will evaporate over time due to Hawking radiation. This has been called the heat death of the universe, and is likely an unavoidable consequence if the universe functions as a closed thermodynamic system (this is another one of those definite maybes). Of course, this will take a VERY long time. Estimates say we have between 10^12 and 10^14 years (between 100 and 10,000 times the current age of the universe).

The second idea is similar to the first, but accounts for the fact that the universe is expanding, and at an ever accelerating rate due to a mysterious force called “dark energy”. What is dark energy? Why, it’s the thing that makes the universe expand (good job, cosmologists)! Given that the universe is constantly expanding in this case, it may never reach total equilibrium. It will, however, become extremely cold. Asymptotically close to absolute zero cold (-273°C/0 Kelvin). As matter and energy become more spread out, the average temperature of space will inevitably fall. You can call this the “big freeze”.

It’s not all doom and gloom though. The Poincare Recurrence Theorem tells us that the universe will return to its initial state after mind-bendingly long periods of time. I’d quote you a figure, but it is literally the largest period of time ever discussed in a published physics article, and would require bizarre notation to even display. If you want a more unconventional take on the end of the universe I’d recommend Asimov’s short story “The Last Question”.