Reading about Big Bang, I'm wondering about this: doesn't the fact that the Big Bang happened imply that there was some kind of state-change: from Big Bang is not happening to Big Bang is happening, and any kind of state-change requires the existence of time. Doesn't this imply that time existed before the Big Bang?
Our Universe wasn’t empty, even before the Big Bang
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Re: Our Universe wasn’t empty, even before the Big Bang
#22Earlier quoted context omitted.
Yeah, it's hard to understand what that means because the furthest point back in time that we know of could be looked at as the beginning of the big bang, even if there was a delay of some kind before the most significant expansion.
I really don’t think it’s hard and basically everyone knows what is meant by this. Physicists just like to be pedantic about the technicalities of what “before” means.
Ex-physicist, which kind of muddies the water, but I'm not trying to be pedantic when I say "I don't know what this means".
Re: Our Universe wasn’t empty, even before the Big Bang
#23Anything thing that talks about "Before the Big Bang" isn't science. It may be philosophy or mathematical speculation, but it is not science.
"Anything that talks about 'the world is round' isn't science. It may be astrology or mathematical speculation but it is not science."
One can do experiments to empirically test the earth is round.
There are no experiments one can do to empirically test things asserted before the Big Bang.
Re: Our Universe wasn’t empty, even before the Big Bang
#24Earlier quoted context omitted.
I really don’t think it’s hard and basically everyone knows what is meant by this. Physicists just like to be pedantic about the technicalities of what “before” means.
Ex-physicist, which kind of muddies the water, but I'm not trying to be pedantic when I say "I don't know what this means".
Totally off-topic, but what made you leave the physics field? If you don't mind me asking.
Re: Our Universe wasn’t empty, even before the Big Bang
#25The title is terrible and doesn’t refer to the actually interesting key point in the article! The idea trying to be expressed is actually that the expansion of the universe is releasing energy, making the concept of “empty” space impossible as even the emptiest areas are still emitting energy.
Well, we knew that to be true already because of quantum foam, and the Higgs field having a nonzero rest energy.
Re: Our Universe wasn’t empty, even before the Big Bang
#26If the universe is cyclical, like has been proposed as a possible theory, then "before the Big Bang" is a perfectly reasonable phrase. Sir Roger Penrose has helped bring attention to the idea, and more recently suggested it may be incorect. It's been around for a while (proposed in the 70's maybe, I think?).
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I'm disappointed by the ease at which people seem to dismiss the phrase as unreasonable. Is it being overly critical without actually knowing enough detail in the field?
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Normally I see very thoughtful responses, so I wonder if there's some collective exhaustion going on. Maybe give a think to some down-time or self-care today? I recommend a light ale or blonde lager with lunch. :)
Re: Our Universe wasn’t empty, even before the Big Bang
#27Earlier quoted context omitted.
Yeah, it's hard to understand what that means because the furthest point back in time that we know of could be looked at as the beginning of the big bang, even if there was a delay of some kind before the most significant expansion.
I really don’t think it’s hard and basically everyone knows what is meant by this. Physicists just like to be pedantic about the technicalities of what “before” means.
If we're talking about a singularity, it's not pedantic. If you reverse time and go back to the Big Bang, it's not possible to define what happens after you hit the singularity, at least according to current theories.
As another commenter pointed out, the article is referring to the "hot Big Bang era", not the Big Bang singularity, so that's what is causing the confusion. It is possible to talk about what happened during and after cosmic inflation.
Re: Our Universe wasn’t empty, even before the Big Bang
#28There's a lot of confusion in this thread about "before the big bang". I was also confused and did some googling and found this explanation from a professor of theoretical physics. It seems that it's actually pretty normal to refer to the big bang as happening after the initial inflationary epoch, but others refer to it as the moment before this. >Do not allow yourself to be confused: The Hot Big Bang almost certainl…
Wouldn’t this be the result of some theoretical physicists moving the goalposts?
It sounds like they feel the commonly accepted understanding of the Big Bang is overbroad. Fine. Find new words to describe the subsets of the event. Redefining the word is just causing confusion.
Re: Our Universe wasn’t empty, even before the Big Bang
#29Earlier quoted context omitted.
"Anything that talks about 'the world is round' isn't science. It may be astrology or mathematical speculation but it is not science."
One can do experiments to empirically test the earth is round. There are no experiments one can do to empirically test things asserted before the Big Bang.
While I agree with the sentiment here, Penrose has come up with a model that does make testable hypotheses about what happened before the big bang with his Conformal Cyclic Cosmology. Now, I think that as a matter of fact, the predictions he made have turned out to not be true, but at least he came up with a way to test them. If I recall correctly, the predictions had to do with patterns in the CMB that would have been left over from black holes in a universe before the big bang, and those patterns ended up not being there. It wasn't the right answer, but that's science.
Re: Our Universe wasn’t empty, even before the Big Bang
#30Earlier quoted context omitted.
"Anything that talks about 'the world is round' isn't science. It may be astrology or mathematical speculation but it is not science."
One can do experiments to empirically test the earth is round. There are no experiments one can do to empirically test things asserted before the Big Bang.
"Dont hypothesize over anything that cannot be immediatly tested otherwise it isnt science" -rcouf1z4gsc