Good grief, how could I think that time exists in non-existence when non-existence is an impossible concept. Existence is eternal, and science can not prove objectively that non-existence is possible
A) Science is not in the business of “proving” things.
Scientists formulate the explanatory & predictive models (eg new hypothesis or, expand or modify existing theory), then TEST the models through OBSERVATIONS (eg EXPERIMENTS, EVIDENCE & DATA).
The words “proving” and “proof” are mathematical logic constructs, like what you see in formulas and equations, with constants, variables, numbers, etc.
The term “proof” is linked to any equation, whereas “proving” and “disproving” are about finding the solutions in mathematical methods, eg solving equations, expanding or simplifying equations, etc.
The mathematical “proofs” are merely statements, not evidence. I will repeat that proofs are statements that are used in parts of the explanations or parts of the predictions in a model. The explanation/prediction which would include the equations or formula, are not true or false until they have been rigorously “tested” (“tests” as in experiments or evidence or both).
The mathematical explanations such as the equations, that you would find in the models of hypothesis or theory, are the “THEORETICAL” side in a model of hypothesis or theory. I will say more about “theoretical” later.
Scientists and mathematicians agreed that proofs and proving are maths, not evidence.
People who lack the education in natural/physical sciences or maths, often used evidence and proof synonymously, especially non-scientist & non-mathematician journalists/reporters, police, judges, lawyers, religious people with no background in either science or maths.
If you want to discuss or argue about sciences, you should know that proof and proving are not evidence.
B) Sciences cannot prove or disprove the universe being eternal or not, but neither can you or anyone.
The more honest & accurate answers would be “we don’t know”.
And btw, about Stephen Hawking:
So do you agree or disagree with Stephan Hawking that time never started at the BB, it already existed, but was just bent. Originally he had the same view as you iirc, however he must have eventually realized the error of 'no time' before the BB. Still, there is a big hole in his theory.
Stephen Hawking Claims To Know What Happened Before The Big Bang.
Hawking is a theoretical physicist, who spent more time with equations...hence a large parts of work are theoretical, meaning maths-intensive concept. He doesn’t do experiments or finding evidence, which means a lot of his views are not science UNTIL THEY HAVE RIGOROUSLY TESTED WITH EVIDENCE.
So a lot of his concepts are untested, therefore they are not scientifically true, and therefore not “science”. Possibly theoretical true, but not scientifically true.
Real science deal with tests and evidence (which is a requirement of Scientific Method), so it concern with what are probable or improbable, where as theoretical science relied on maths and equations, so what they assume are either possible or impossible.
So until theoretical physicists can one day test his theoretical model, such models are not yet science.
You should know that General Relativity, Quantum mechanics, particle physics, the Big Bang theory, all started off theoretically, but parts of them were tested, but some of them remain purely theoretical.
For instance, Peter Higgs’ Higgs field & boson started out only as theoretical concept, but in 2012 or 2013, it was finally tested and verified in one of LHC experiments at CERN.
Likewise, Einstein’s GR on gravitational lensing was theoretically sound, but only experiments tested this concept to be true. However, something like his concept on “wormhole” in General Relativity remained purely theoretical & hypothetical, because it is untested.
A lot of things Hawking say are only theoretically possible, using maths that are beyond my grasp, but if they untested then his concepts are not (yet) science.
Multiverse is one of those purely theoretical models, as are String Theory, quantum gravity, etc. However, the last one, quantum gravity, given time, may be more scientifically plausible than Multiverse.