56 votes

Is the Big Bang a theory or a model?

Back in the good old days, we used words like theory, model, hypothesis, law and so on, and their meanings arose from how the words were used, and dictionaries organised these senses - just like other ...
James K's user avatar
  • 119k
27 votes

Could the Methuselah star be evidence that there was a universe before this one?

First, if the Big Bang did originate with the collapse of a cyclic universe, the collapse reached densities and temperatures sufficient to not only ionize matter from the previous cycle, but to ...
Christopher James Huff's user avatar
23 votes

Is the Big Bang a theory or a model?

My understanding is that the "big bang" (which I am taking to be a synonym for $\Lambda$CDM cosmology) is a model. It sets out a (relatively) simple framework, starting from a set of ...
ProfRob's user avatar
  • 149k
15 votes

Why do cosmologists assume that inflation began shortly after the Big Bang, rather than at the exact start?

The universe cannot have begun in an inflationary phase. Note that it is not necessarily the case that there was a phase that preceded inflation. However, if there was no phase preceding inflation, ...
Sten's user avatar
  • 4,511
7 votes

Is dark matter made from the particles that had charge but no mass in the early part of the Big Bang

Charged, massless particles would be a form of "hot" dark matter. i.e. A form of energy density that was relativistic at the epoch of structure formation and of course, still relativistic ...
ProfRob's user avatar
  • 149k
6 votes

Was the Big Bang an event within a preexisting Universe, or did it mark the beginning of the entire Universe, beyond just the observable Universe?

Could it be that the Universe is truly infinite It looks like it is infinite in space in all directions, and infinite in time in one direction. Going back in time one reaches a singularity. It is ...
James K's user avatar
  • 119k
6 votes

Is the expansion of the universe proof of the big bang?

Whether the big bang is a theory or a model, it cannot be "proved". Scientific models and theories can only be falsified. I think what you mean is - are there other pieces of evidence that ...
ProfRob's user avatar
  • 149k
5 votes
Accepted

why couldn't atoms form in the early big bang?

In an atom, the electrons are held around the nucleus by electromagnetic forces. The electrons have a negative charge, and the nucleus has a positive charge, and these attract. But if you give the ...
James K's user avatar
  • 119k
5 votes

Big bang cosmology

According to conventional Astrophysics: The main evidence supporting the Big Bang theory comes from multiple observations and scientific principles: Cosmic Microwave Background (CMB): The detection of ...
Brendan Darrer's user avatar
4 votes

Is dark matter made from the particles that had charge but no mass in the early part of the Big Bang

No, because if "dark matter" had no mass, it wouldn't be dark matter anymore. Keep in mind dark matter needs to exert gravitational force, and massless particles do not exert gravitational ...
Allure's user avatar
  • 4,245
3 votes

Was the Big Bang an event within a preexisting Universe, or did it mark the beginning of the entire Universe, beyond just the observable Universe?

You're asking about something that's beyond the realm of well-understood physics, so a lot of it is speculation. However, people work on the idea, so it's not impossible. The key words you want to ...
Allure's user avatar
  • 4,245
3 votes

If the energy density during inflation were lower, how would the CMB look in comparison to the observed CMB today?

We don't know the energy density during inflation. This should immediately tell you that it doesn't (directly) impact any of the observables that we are able to measure. Even though the inflation ...
Sten's user avatar
  • 4,511
3 votes
Accepted

Big Bang vs movements within a supercluster

The peculiar velocity of a galaxy does not override the Hubble flow. Rather, it is relative to the Hubble flow. Hubble (and others after him) looked at the redshifts of individual galaxies and ...
Mark Foskey's user avatar
  • 3,896
3 votes

Are we really 13.8 billion light years from the big bang

The universe isn't space. It's spacetime. We are 13.8 billion years away from the big bang in the time direction. We aren't 13.8 billion light years away from it in any spatial direction, nor any ...
benrg's user avatar
  • 3,822
2 votes
Accepted

Big bang cosmology

The main evidence of the Big Bang is the cosmic microwave background (CMB). You can find details here: https://en.wikipedia.org/wiki/Cosmic_microwave_background. The CMB is the remnant of the Big Bang....
Universe_explorer080's user avatar
1 vote

Could vacuum expansion arising from the Big Bang be a consequence of entanglement?

Firstly, AdS/CFT has an entirely different notion of what "emergence" is. Emergence in this case is that a bulk subregion arises because of a type III$_{1}$ von Neumann algebra on the ...
VaibhavK's user avatar
  • 125
1 vote
Accepted

Could macroscopic primordial black holes have created metals shortly after the big bang?

I am a new user so if you find any error in my answer kindly correct it. Perhaps, but indirectly Heavier elements are made in nuclear furnaces, where processes such as nucleosynthesis/neutron capture ...
Arjun's user avatar
  • 1,256
1 vote

Could inhomogeneities or topological defects break the fundamental symmetries of the Universe?

The answer to your question is affirmative. In principle, the Poincare invariance may be violated at cosmic scales. A possibility for this may be coming from theories more fundamental than Relativity ...
Michael_1812's user avatar
  • 1,231

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