Nobody really seems to elaborate much what what is expected to happen in the heat death of the universe. Is it basically that every galaxy collapses into the supermassive black holes at its center, then those black holes Hawking-radiate away until they’re gone?
Everything that can decay, does decay. Including Black Holes, possibly protons, etc. Basically, everything reaches a minimum energy level.
The end result, after an unimaginably long time, would be nothing left but photons, neutrinos, and gravitons, all redshifting away into the next best thing to nothingness as the Universe continues to expand.
‘. . . [H]ere and there chaos may temporarily recede and quality flare up, as when cathedrals are built and symphonies are performed. But these are temporary and local deceits, for deeper in the world the spring inescapably unwinds. Everything is driven by decay. Everything is driven by motiveless, purposeless decay.’
Peter Atkins in Creation Revisited
It will be duller than a party of depressed sloths.
The single most depressing thing about the entire universe is this. It’s a terminal ‘this too, shall pass’.
I guess my main question is this: do these things necessarily have to go through the step of being consumed by a black hole and re-emitted as Hawking radiation, or are there other possible ways that they reach that end state?
Insufficient Data For A Meaningful Answer
While that’s certainly one way for it to happen (and the only known way to convert other particles to gravitons), most grand unified theories (theories which unify the Strong and Weak Forces, not necessarily including gravity) predict that the proton is unstable even aside from black holes, and would eventually decay into a positron and some mix of photons and neutrinos. The positron, in turn, would eventually find an electron to annihilate with (it wouldn’t have to go far, if the decaying proton were part of a neutral atom), converting those, too, to photons. While nobody knows yet which grand unified theory is correct, I don’t think there’s much doubt that some one of them is, which means that proton decay is pretty likely (it’s just the details, like how long it takes, that remain to be worked out).
Isn’t it quite unlikely that most of the matter/energy in the universe will ever get near a black hole? I thought current theory held that everything will grow farther and farther apart—first galactic clusters, the galaxies, then possibly even material within galaxies—and all of the matter will slowly cool… and eventually, just possibly, all those protons will even fall apart one day (not that there may be much for the products of their decay to run into by that point).
[SPOILER]Let there be light!
Unless dark energy kicks it up a notch at some point in the future, pretty much everything that’s reasonably gravitationally bound will stay that way despite the expansion of the universe. Eventually the galaxies in our local group will coalesce into one large galaxy, meanwhile galaxies outside the group will drift farther away and out of sight. But our local Pangaea-style galaxy will still remain intact.
Here’s an interesting look at some of the very very long term processes that characterize the end of the universe.
How can the energy disappear? Where does it go? How can the universe begin with mind boggling amounts of energy and end with none?
That is an interesting chart. The last entries list an amount of time so unfathomly great, I think it could be reasonably assumed, that if a special chamber could exist for the that whole duration, consisting of an unaging , constantly typing monkey,that amonst the trillion, trillion, trillion, trillions of trillion trillion trillions…etc pages of gibberish he produced, would also be the entire collected works of writing ever written by any person in human history, as well as perfectly translated copies of each in every language that was ever spoken.
The probabilities of the monkeys typing at random scenario are fairly straightforward to compute. I think you will find that even with the large timeframes described you won’t get much more than a small length on non-gibberish text.
This just in: Not so fast on the dark energy, and not on the dark matter a bit as well.
Those pesky artifacts of observation might well be in our way again.
Tris
Conservation of energy is a local property, not a global one. If you draw a box anywhere in the Universe, then the change in the amount of energy inside the box is equal to the energy flow through the walls of the box. But the entire Universe is not a box.
Wolfram Alpha’s already been asked the last question;
Oh, so they finally got around to fixing that. For all the many ways Alpha has of saying “I don’t know”, it took them long enough.
TheMorbidAtheist’s take on it: