I may be off the mark with what you believe, but just in case:
It's a common misconception that the big bang originated at a specific point. The big bang seems to have happened everywhere simultaneously, so it wouldn't be true to say that gravity is pulling everything back toward a point of origin.
Here's an excellent video on misconceptions about the universe: https://www.youtube.com/watch?v=XBr4GkRnY04
(Ironically, the video was created because the creator was a scientist, yet they fell into the trap of believing something incorrect to the point of being publicly mistaken about it. The universe is extremely counterintuitive!)
And infinite universe brings strange phenomenons, like our doppelgangers far away, that are exactly like us.
As a non-physicist, wording it like that made a lot that I didn't understand suddenly click.
Until the big bang happened there wasn't any "where" for anything to happen in
I have come at the question a bit like you have, starting with Faraday and Maxwell for the electromagnetic theory, adding Lorentz and Einstein for the time and space dilation effects of general relativity. And when you start looking at light as an expanding wavefront alternating between a magnetic form and a electrostatic form and thinking about how the frequency of that oscillation relates to the other fundamental constants in the universe like the speed of light and the planck constant, you might start to wonder, as I have, whether a wavefront at the speed of light would mass appear as a side effect because it was distorting space time so hard it was dragging it around?
Its a lot of fun to think about.
- Macroscopic phenomena are in turn governed by microscopic phenomena, where the strong and weak forces dominate, so I would say our dimension is equally governed by those. At high energies we know the electromagnetic and weak forces combine into the "electroweak" force, and it is commonly hypothesized that at even higher energies (such as those seen only during the very beginning of the Big Bang), all of the forces are unified. If you already knew that or were talking about something else, my apologies.
- There is the concept of the Big Crunch, where gravity would pull the universe back to a single point, perhaps in an infinite cycle. To the best of our current knowledge though, the expansion of the universe is actually accelerating, and gravity will not overtake it.
For example, a really small object can have a length smaller than the Planck length, but we wouldn't truly know how long it was because the Planck length acts as a fundamental limit on the precision/granularity of our measuring instruments.
Would that be, to all intents and purposes, undetectable by us then? If so then that might be a possible explanation of "dark matter", assuming all these things were individually smaller than the Planck length.
In so far as our means for measuring particles doesn't change; namely, smashing things together at extremely high energies.
If you suppose that there are methods for measuring sub-Planck length areas then one must assume that they involve either: energies lower than those believed to be needed (which doesn't necessarily come to a solution, but pushes the problem to even higher energies and shorter lengths) OR that there is a default force that keeps space-time stable unless high energies are approached.
Note that both notions are mere speculation, the first on logic and the second on intuition about phase changes in states of matter.
Just as the big bang didn't happen in a single place, a Big Crunch wouldn't be a contraction back to a single point. Rather, the scale factor [1] that characterises cosmic expansion would simply(!) decline back to zero.
To a first order approximation (e.g. in the FLRW perfect fluid model), a Big Crunch would resemble a time-reversal of the standard big bang cosmology.
In our universe, time reversal results in galaxies appearing at a comoving observer's horizon, and everything inside the horizon becoming denser and hotter.
Ultimately the density and heat is expected to result in beyond-the-Standard Model physics in the matter sector, and (hopefully) new physics in the gravitational sector.
We don't really know what those physics will be. Everyone hopes for something that prevents a gravitational singularity from forming, but so far what we have in terms of possible stabilizers are conjectural at best.
The time-reversals of Big Crunch and the usual-forward-time big bang cosmology with structure formation relate to the BH information loss problem. For a non-eternal BH when we time-reverse from i+ we have a gas of Hawking radiation that collapses into a time-reversed BH which eventually emits matter with much less (Boltzmann) entropy -- ions, molecules, dust, stars and even the things orbiting them. (A time-reversed stellar BH likewise will eventually spit out a white dwarf or neutron star with their respective complex layerings). How does a time-reversed BH "know" how to spit out whole stellar-mass objects when only time-reversed Hawking radiation fell into it? Most quantum gravity programmes hope that strong gravity[1] produces an environment where this sort of (time-reversed) structure formation is likely.
Flipping the arrow(s)-of-time is extremely useful for reasoning in a setting in which strong gravity is important, and extra-underlines the question of why we have the arrow(s)-of-time we do in the first place. "Boundary conditions did it" is pretty unsatisfying.
- --
[1] i.e., where the radius of curvature is on the order of the Planck length; this mostly comes from the non-renormalizability of perturbatively quantized gravity (where we quantize perturbations of a background metric) and from work in finding the effective field theory limit of semiclassical gravity; generally it's very close to a gravitational singularity and -- depending on the censorship conjecture -- always invisible to outside observers.
That the default or base state of existence may not be nothing, not "not even nothing", but rather Everything. ...
Instead of viewing the origin of all reality/creation as things being added to a canvas of blackness/emptiness/voidness, rather consider that "Existence" may be a subtractive process: akin to holes being poked into a canvas of white, or bubbles in a boiling liquid.
(I mean even before the Big Bang, or the classic "Who Created God"/Prime Mover/First Cause question – humans are given to assuming that the start of anything must be Zero or Nothingness, that the end of everything is Oblivion, and that may not be the case.)
Our existence is a "filter", our perceptions being a very limited subset of everything that's around us, of select wavelengths and frequencies and etc. This entire universe could just be a transient bubble inside a flood of Everythingness. [0]
[0] https://en.wikipedia.org/wiki/False_vacuum#Existential_threa...
Axiomatic Set Theory is taught starting with the empty set as an axiom and along with a small number of additional axioms, and from that you can build the integers and rationals and real numbers as well as an impressive hierarchy of different infinities. And one thing that's proved is there is no largest infinity, no set that contains all sets. There isn't an Everything set that's consistent with the Peano axioms.
However, you could build the entire system starting with the Everything set and similarly modify all the axioms to be analagously subtractive rather than additive, deriving in some sense every inverse theorem, including that there is no empty set, no Nothing.
When you do this you immediately at working with insane objects and intuition fails miserably in a way that building the other way doesn't.
This certainly fits with the idea that the universe is an attempted "ordering" bubble in a liquid of everything
As for your second question, you might want to start with something like Feynman’s book QED.
Is this even a meaningful question? My understanding of "where" is that it's referring to a location within space.
- Is there a “quantum” of space? Where/how is location stored?
- If electromagnetic repulsion is what makes matter “take space”, and if virtually all macroscopic phenomena are governed by electromagnetism and gravity, then could this reality be said to be “gravelectromagnetic”, and might there be other “dimensions” governed by other forces, like “cones” extending in differing “directions” from the subatomic scale? [0]
- Could gravity be the result of space trying to deflate/return to the pre-Big Bang singularity, kind of like pulling magnets apart? i.e. is gravity the “opposite” of, or a reaction to, “space?”
[0]: http://i.imgur.com/6meZmc2.png