Survey Shows that 51% of Americans Question the 'Big Bang Theory'

[Mr. Morden]

The pollsters asked the question incorrectly; they made the statement, "The universe began 13.8 billion years ago with a big bang."  Well, that's (1) almost certainly not true, and (2) more importantly not what the big bang theory purports to explain.  The big bang theory is an explanation of the expansion of the development and expansion of the universe, not the creation of the universe.  According to the big bang theory, the universe existed as a singularity before the big bang actually happened, and the big bang theory does not address how it came into existence.

Not exactly.  The instant of the Big Bang is the beginning of time.  There is no "before".  As I recently saw someone else describe it, talking about "before the Big Bang" is like talking about something being north of the North Pole.  The concept is incoherent.

In any case, I'm reasonably confident that there was a Big Bang, but to say that it was exactly 13.8 billion years ago simply because of the Planck results last year…..that's still a sketchy proposition.  Heck, if some of the more exotic theories about the inhomogeneity of large scale structure are correct, then the age of the universe could vary by as much as billions of years depending on whether you make the measurement in a supercluster or a void.

[Mr. Morden]

The pollsters asked the question incorrectly; they made the statement, "The universe began 13.8 billion years ago with a big bang."  Well, that's (1) almost certainly not true, and (2) more importantly not what the big bang theory purports to explain.  The big bang theory is an explanation of the expansion of the development and expansion of the universe, not the creation of the universe.  According to the big bang theory, the universe existed as a singularity before the big bang actually happened, and the big bang theory does not address how it came into existence.

Not exactly.  The instant of the Big Bang is the beginning of time.  There is no "before".  As I recently saw someone else describe it, talking about "before the Big Bang" is like talking about something being north of the North Pole.  The concept is incoherent.

In any case, I'm reasonably confident that there was a Big Bang, but to say that it was exactly 13.8 billion years ago simply because of the Planck results last year…..that's still a sketchy proposition.  Heck, if some of the more exotic theories about the inhomogeneity of large scale structure are correct, then the age of the universe could vary by as much as billions of years depending on whether you make the measurement in a supercluster or a void.

There would have been no time relevant to the universe, because at that point, time would be immeasurable pursuant to the Penrose–Hawking singularity theorem; however, there is nothing in current science that precludes the possibility of multiple universes or anything outside of the singularity.  And this begins to cross into a point of physics that I really don't understand, but the point is that the big bang theory does not explain when (or how) the universe began; it can only explain its development.

Fair enough that it doesn't explain "how" the universe began.  But technically, saying that "the universe began with a big bang" isn't saying anything about "how".  It's just saying that the big bang was coincident with the beginning of the universe.

(Though yes, there could be some kind of multiverse scenario, but whether you call those other universes part of our universe or not is a matter of semantics.)

[Mr. Morden]

While scientists are extremely confident about the 13.8 billion figure...

I would dispute that.

EDIT: By which I mean, sure, 13.8 billion has got to be pretty close to being right if the Lambda-CDM model is correct, but Lambda-CDM being correct isn't something I would bet my life on.  There could be some complicating wrinkles.

[Mr. Morden]

While scientists are extremely confident about the 13.8 billion figure...

I would dispute that.

EDIT: By which I mean, sure, 13.8 billion has got to be pretty close to being right if the Lambda-CDM model is correct, but Lambda-CDM being correct isn't something I would bet my life on.  There could be some complicating wrinkles.

There is plenty of debate over the nature of the cold dark matter in the standard Lambda-CDM model. But most competing models that would result in a substantially different age of the universe (t₀) have failed to match all the known observational data, particularly data from gravitational lensing and colliding galaxies. Other extensions of Lambda-CDM typically involve parameters that leave t₀ largely untouched. So I would say that most scientists are extremely confident in the value of t₀ within a reasonable experimental and theoretical error.

I don't know, Muon.  Dark energy still feels something like a late 20th / early 21st century version of "the ether" to me.  I still feel like there's a decent chance that we'll learn something that will change our understanding of GR enough that it won't quite be vanilla Lambda-CDM.  Perhaps Lambda-CDM with some interesting wrinkles that mean that it's not quite 13.8 billion years old.

What do you think of folks like David Wiltshire, who claim that the conventional shortcuts that people take in averaging the spacetime metric in a way that kind of ignores large scale structure is leading them astray ( http://arxiv.org/pdf/0912.4563.pdf )?  Wiltshire goes so far as to say that this can explain away dark energy, which puts him outside the mainstream consensus.  But I think there are others (though still a minority, I think, though I'm no GR specialist) who would support some milder version of this, which would still mean that you could have a universe without a single unique age, because of the differential in time dilation between an observer who's in the middle of a void and an observer who's in the middle of a huge galaxy cluster.