Am I correct in saying that the Big Bang was not an explosion but was rather an expansion, a rapid increase in the volume of the universe?
I believe the correct description is “horrendous space kablooie”.
Well, apparently the current scientific consensus is that first of all there was a rapid increase in the volume of the universe, but that is not the Big Bang as such, it is called inflation. Then the Big Bang happened, in the space created by inflation. (I think space keeps on expanding too, but nearly as fast as it did in the inflation stage.)
I don’t claim to really understand this stuff, but it appears from that as though the Big Bang may have been more explosion-like than you might have thought (depending on your definition of explosion, I guess).
Isn’t an explosion just a rapid expansion, anyway?
Well, inflation, apparently, is just an expansion of space, and is very cold, whereas the Big Bang proper involves matter and energy, and is very hot. The latter seems much more like your typical explosion.
Relative to the previous state, explosion might be okay to say. For getting one’s brain around what happened, saying it was and explosion or 'BANG" just defines it in terms that are too simplistic… and draws a picture for most people that isn’t very accurate.
[quote=“njtt, post:3, topic:527658”]
Well, apparently the current scientific consensus is that first of all there was a rapid increase in the volume of the universe, but that is not the Big Bang as such, it is called inflation. Then the Big Bang happened, in the space created by inflation. (I think space keeps on expanding too, but nearly as fast as it did in the inflation stage.)
Those blog posts use “Big Bang” in a way I’ve never heard anyone else use it. When most physicists and cosmologists refer to the “Big Bang”, they mean the “moment of creation”; in other words, if you “run the film backwards”, the Big Bang is the moment when the Universe becomes infinitely hot and dense. Inflation happened very shortly (about 10[sup]-36[/sup] seconds) after the Big Bang. The Wikipedia article on inflation uses this more common nomenclature.
There was supposed to be a horrendous space kablooie!
No. there wasn’t. the Primordal Pre-Universe creature was supposed to cover his mouth before he sneezed.
His/her mom scolded him/her severely.
Well, it was news to me too, but the posts are very recent and by an actual astrophysicist who is clearly being quite deliberate in the way he is using these terms. And it is not just some random blog that someone thought they would start. Not just anybody can be on Scienceblogs, it is by invitation only, I believe. I would venture to suggest that these posts probably reflect the latest informed consensus on the subject. What Wikipedia says, or what people may have read in some popularizing work or other is far more likely to be either outdated or misleadingly oversimplified (or both)
IMO Big Bang is not a very accurate description since it suggests the event was mainly about sound.
I’ve seen the term “Big Bang” refer to either the single moment at t = 0, or to the entire process of expansion of the Universe, which is still going on today. In neither sense is it really accurate to say that inflation happened, then the Big Bang.
You’re thinking of the Great Green Arkleseizure. That theory has long since been discredited.
I was just reading in a book (5 Ages of the Universe) that in the Universe’s first few minutes it expanded from pretty much nothing to an estimated 20 billion light years diameter.
That’s some bang!
Honestly, it makes sense that “Big Bang” is a poor name for the theory - it was first used by people opposed to the theory who were trying to belittle it. The problem is that the term got stuck regardless of its accuracy.
(And, really, it’s not half bad as catchy names go for complex scientific concepts. Especially compared to, say, chromodynamics and quarks.)