Space and time are related, and expanding rapidly since the Big Bang (though there was a time in the early universe when the expansion rate was faster).
Observing the edge is effectively looking back in time, to see the conditions of the universe closer to the time of the Big Bang.
New telescopes keep expanding that edge, and new particle colliders (such as those at CERN or Fermilab) keep "bashing 2 rocks together to make fire" - recreating the conditions of the Big Bang to see what comes off.
What I'm not sure about is whether the speed of light (assumed to be constant) is correlated with the size of the observable universe. Perhaps a physicist could shed some light on that question. Relativity means that galaxies that are moving at the speed of light away from one another (one travelling at c, another travelling at -c) have a relative velocity of higher than the speed of light (|c| + |-c| = 2c).
There's also the theory of the One Electron Universe, which I quite like (though that reveals my bias as an electronic systems engineer). Perhaps what we see is the One photon universe.
https://en.wikipedia.org/wiki/One-electron_universe
The terms are:
v is the relative velocity between inertial reference frames,
c is the speed of light in vacuum,
β is the ratio of v to c,
t is coordinate time,
τ is the proper time for an observer (measuring time intervals in the observer's own frame).
If we could compare the time as we know it (based on the SI unit of seconds using an atomic clock) against the time at the singularity at the centre of the universe, we could figure out whether we're in a black hole, whether we're at the event horizon, or whether we're outside.
But we would have to assume space is a vacuum, which isn't entirely true.
Finding a way to reverse the expansion of the universe would imply time travel being possible. It hasn't happened yet, but perhaps that's just a technological limitation. And if you ask my Mac, then Time Machine is very much possible - that's just the name of the backup system.
The question starts to become very philosophical if there is a backup system for this universe. Everything being saved, for eternity, in infinite time. It would require very advanced computational power and storage, but it would probably work in binary (but that's just the kind of thing a computer engineer would say).
Maybe, though, the observable universe is rotating clockwise around a centre that is in the unobservable universe, and time is just a measure of how many rotations have been made since the Big Bang.
https://cds.cern.ch/images/CERN-HOMEWEB-PHO-2022-023-1
Observing the edge is effectively looking back in time, to see the conditions of the universe closer to the time of the Big Bang.
New telescopes keep expanding that edge, and new particle colliders (such as those at CERN or Fermilab) keep "bashing 2 rocks together to make fire" - recreating the conditions of the Big Bang to see what comes off.
What I'm not sure about is whether the speed of light (assumed to be constant) is correlated with the size of the observable universe. Perhaps a physicist could shed some light on that question. Relativity means that galaxies that are moving at the speed of light away from one another (one travelling at c, another travelling at -c) have a relative velocity of higher than the speed of light (|c| + |-c| = 2c).
There's also the theory of the One Electron Universe, which I quite like (though that reveals my bias as an electronic systems engineer). Perhaps what we see is the One photon universe. https://en.wikipedia.org/wiki/One-electron_universe
Hopefully this rambling makes sense to someone!