What could be at the end of the universe?

Answer 1

"Could"? "Could" be anything, I guess, since we have no idea of the universe will even HAVE an end.

There are a number of zany ideas, of course, and we don't really have enough evidence to eliminate any of them. The universe might keep expanding forever, with everything getting further and further apart. When all the stars have exploded or burned out, they may all fall into the supermassive black holes that we believe exist at the centers of many (or most?) large galaxies.

If there's a little more mass in the universe than some scientists currently believe there is, the expansion may be slowed down, and everything may be attracted to a single point, in a cosmic "Big Crunch" that may be the end of the Big Bang - and perhaps the genesis for the next "Big Bang".

Or perhaps Sir Fred Hoyle will be proven to be right after all, that the "Big Bang" never happened and that a "steady state" universe will exist forever much as it exists now. Remember that Hoyle, who invented the term "Big Bang", meant it as an insult. The Big Bang theory does answer a lot of questions, but there is other data that calls it into doubt.

Remember, we're still new at this cosmos-understanding stuff. We KNOW very little, and have vast theories made up of a few wisps of facts held together with an enormous spiderweb of guesses and suppositions. Never let your nice theories get in the way of actual facts.