I Big Bang Theory: Spacetime or Matter First?

[omie]

My question comes from the following confusing aspect of the big bang theory. Since at different stages during development of the current universe, we know that fundamental particles, atoms and large masses started to form. And if all large masses are embedded in spacetime when during the development of the universe did the spacetime form? . But it seems to me, that all aspects of matter, would require a spacetime. It is not only large masses that depend on the spacetime but even small particles. Meaning if you require to create a universe the foundation of it must consist of something super strong. Or that space time was always there, and all the mass was just compacted into a point. Am i being silly?

 

[PeterDonis]

at different stages during development of the current universe, we know that fundamental particles, atoms and large masses started to form.

Careful. The quantum fields of the Standard Model, which is what "fundamental particles, atoms, and large masses" are all built on, were always there. But before the end of inflation, those fields had no energy in them; they were all in their vacuum state. At the end of inflation, the energy stored in the inflaton field was transferred to the Standard Model fields (this process is called "reheating", which is somewhat of a misnomer since there had been no previous "heating" or "unheating"). But that didn't create those fields; it just transferred energy to them.

it seems to me, that all aspects of matter, would require a spacetime

More precisely, quantum fields such as those in the Standard Model require a background spacetime to exist. At least, that's how quantum field theory is currently formulated. One reason why physicists are searching for a theory of quantum gravity is to try to find a theory in which spacetime and quantum fields are both aspects of something more fundamental. We probably won't be able to answer questions like "how did the universe ultimately originate?" until we have such a theory.