To my knowledge, we also have zero evidence that they didn't exist. Nor have we ever observed matter/energy appearing out of thin air vaccuum, so it seems unlikely to me.
Can time really exist if there was no frame of reference to measure it? We can only detect it by motion or entropy. It's the only way of "time". So if there was some point where there was nothing that moved, then time wouldn't exist.
For that matter, there's no way of measuring if time is even consistent. If it were constantly speeding way up, or slowing way down, we'd have no way of knowing.
Time is just a figment of our imagination so we can keep track of movement. Just like magenta isn't a real color.
Well, yes and no. Time is a concept derived from a change in state. There is no “real” time. If the universe before the Big Bang existed in a static state, then the concept of time itself becomes meaningless. So in that case, it would be “before time” in a sense
My layman's understanding is that virtual particles can and do emerge from vacuum, but in ways that usually cancel out before affecting anything. Occasionally it does affect normal stuff - see the Casimir effect acting on surfaces very close together.
I personally suspect this is an explanation for dark matter and a possible origin of the universe.
If there's tiny bits of stuff and anti-stuff blinking in and out of existence, anywhere there's a big fat nothing, both halves should still exhibit gravity before blipping back out. It wouldn't show up as normal matter because it spends most of its time not existing. The vacuum really is empty... on average. It just hums with enough short-lived quantum shenanigans to have nonzero mass.
And if this follows a steep curve for distribution, then it's like blackbody radiation. A hot rock will overwhelmingly emit photon wavelengths near the peak, for any given temperature, but in theory any temperature can emit any wavelength. It just happens with vanishing rarity as you get up into the spicy photons. If vacuum will occasionally fart out a particle and antiparticle, then very occasionally it should fart out two particles and antiparticles, together. And with vanishing rarity it can theoretically fart out an arbitrary quantity of mass, alongside a negation that is presumably equal. But if that's off by a little bit - if it's allowed to be off by a little bit - then an equally arbitrary quantity of mass will remain. Even if the masses have to match exactly, they could recombine in ways that produce angular momentum and never properly rejoin. And if vacuum produces gravity, well, anything that's left will accelerate away in all directions.
On cosmic timescales it's possible that matter just kinda happens. We'd be left with the question of why the fuck that's how anything works, and where all this quantum vacuum bullshit came from. But creationist cranks would have to retreat back to the first sentence. In the beginning, there was nothing. And it was slightly heavy.
Yeah, I suspect that the universe may expand and contract, so likely all the matter in the big bang came from it all being compressed from the previous cycle.
I also think all total matter gets distributed the same way each cycle, so I guess I think all matter that exists now is the same matter that has existed always.
I also think each cycle, everything happens the same way deterministically, even though it would be exciting to see if maybe events happen differently each cycle.
My crackpot theory is that there's a universe inside each black hole and we're currently inside a black hole. All of the matter that a black hole ingests feeds into a big bang on a separate timeline.
The big bang was a singularity where our understanding of time and space breaks down. Well a black hole is the same thing.