Not just me and you, but our planet..gone. Our solar system and galaxy, The Milky Way...gone.
Then, the universe itself keeps on expanding at an ever-increasing rate while the components of which it's made break down into more and more basic components. Interactions and reactions happen less and less frequently, and then hardly at all and then never.
And the universe, then, will also be gone.
Did I say gone?
Or did it ever exist?
I have already accepted my fate, so who cares what happens after I depart?
Not that you departed per se, but what happens WAAAY after that. I'm CURIOUS.
I suppose that depends on one's definition of the universe. Is it one component in a multiverse? Is it universal laws? Is it the matter and energy that composes it? Is it the boundaries of what we in our limited capacity as an observer can perceive? Is it the universe at any given moment in time?
The question supposes that the universe is the matter and energy that compose it. Hypothetically, as the entropy of the system approaches infinity, all matter and energy will still exist in some form, just strewn out at unconscionable distances moving apart from each other at relativistic speeds, that is if the laws of conservation of energy still exist at that point. I think a better question is: does anything exist if it doesn't interact with anything else?
Universe, as a default, is often used to refer to the known universe (The part we can see/observe), but, in reality, refers to everything.
So, Known Universe, is what we are discussing with the Big Bang for example.
I think things exist, even if in isolation.
I also think, that as spacetime is a thing, and not truly 'empty", there is probably no point at which you are NOT in spacetime.
So, in the riddle about the tree falling in the woods, if the word "noise" is used, the answer is "no", as noise is the perceived sound....but if the word "sound" is used in the riddle, the tree DID make a sound, even if no one was there to hear it.
The sound was a propagating wave.
Ripples in spacetime are a result of something disturbing it...the way a pebble makes ripples in a pond when dropped in, etc.
So, when things are cold and spread way out, and condensation can occur, we get a new bang, and its off to the races again.
There's a really good thought experiment based on the work of Victor Stenger, it goes something like this...
Imagine a cube of nothing - a total absence of anything - 200 miles x 200 miles x 200 miles. Place yourself in the middle of this cube. What do you see? Nothing. Now, wait in the centre of this cube for 20 years and what do you see? Nothing, right. After 20 years of nothing let's travel, 50 miles in any direction and see what we can see. The answer is, not surprisingly, nothing. So what? Well this demonstrates that 'nothing' has translational symmetry (or invarience if you prefer) in both space and time. Good.
Let's go to the next piece of this thought experiment, let's say we carry out an experiment of dropping a hammer 1 meter and recording how long it takes to hit the ground. We then wait 20 years and repeat the experiment exactly the same way, we will find that the results are the same. Next time we relocate the experiment to New York and yet again we find the results are the same. This means that the 'laws' of Physics have translational symmetry in space and time too.
This not only works in Newtonian Physics it also works in Quantum Physics (for example, field gauge symetry gives us the conservation of electric charge).
Now the really interesting bit... this means that there needs to be no change in the laws of physics to get from a Universe full of nothing to the Universe we inhabit today.
We could all be just patterns in a void or to use a paragraph from Douglas Adams;
'Arthur looked. Much to his surprise, there was a velvet paisley-covered Chesterfield sofa in the field in front of them. He boggled intelligently at it. Shrewd questions sprang into his mind.
"Why," he said, "is there a sofa in that field?"
"I told you!" shouted Ford, leaping to his feet. "Eddies in the space-time continuum!"
"And this is his sofa, is it?" asked Arthur, struggling to his feet and, he hoped, though not very optimistically, to his senses.'
How can there be a floor in a cube full of nothing? What is it made of? Plus, if you are in such a cube, it isn't really empty, is it? A case of the investigator tainting the experiment?
Indeed, that may account for The Big Bang. However, I've come to appreciate that the "space" in which branes exist is not the same sort of "space" we live in day-to-day. For example, while we can only know in a direct way the three physical dimensions, other things/stuff/beings may exist in our three-dimensional space that don't interact with our space by existing in another dimension and that no bumping or colliding seems to ever take place.
We have a similar problem with a lot of what we know or speculate about in terms of physics "at the edge" in that we can't apply our everyday categories of experience to such things as The Big Bang. For example, our current speed of light may not have happened until billions of years after The Big Bang event. Likewise with string theory. "What are strings made of?" Well, obviously it's not something out of everyday experience. They, like all subatomic particles, are not "made" of anything you'll find on the periodic table of elements. We can say they are "pure energy," but WTF does THAT mean in any way we can possibly understand?