Re: big bang problems
- From: Gareth McCaughan <Gareth.McCaughan@xxxxxxxxx>
- Date: Thu, 30 Apr 2009 01:59:29 +0100
Marc Rasell wrote:
I was listening to a lecture yesterday by Dr DeGroot who is an
astronomer and has served in several observatories.
(For the benefit of anyone who -- apparently unlike Marc --
finds the principal value of such descriptions to be their
use in identifying the person in question, rather than of
shedding a vague aura of scienciness and authority: this
is probably Mart de Groot, who does indeed appear to be a
competent astronomer with a respectable career behind him.)
He looked at the strenths and weaknesses of the theory, and
essentially in order for such a big bang to work there are very finely
tuned things that need to take place.
1. the creation of positive and negative particles must not be equal
or they would cancel each other out. But even if there was an
imbalance it is under a very limited scope, too much or too little and
it doesn't work.
I do not believe that he said "positive and negative particles".
I'm guessing that he was referring to the relative quantities
of matter and antimatter.
2. the size of the explosion must be just right, too little and the
universe collapses and too much and it is too dispersed.
I gravely doubt that he referred to "the size of the explosion"
either, but I'm guessing that this is a reference to the density
of matter in the universe -- it seems to be very close to the
value at which the expansion of the universe *only just* continues
indefinitely, and we'd expect that deviations from that value
grow exponentially over time, so it seems like it must have
been very very very very close to the critical value at very
early times.
The theory of "inflation" is generally considered to provide
a good solution to the puzzle, by the way.
He quoted some figures, I think one was 1 in 10 to power 40 and the
other was 1 in 10 power of 60 which gives some idea of how finely
tuned it would be to have a universe.
10^-60 would be a rough estimate of how close the density of
matter and energy in the very early universe must have been
to the critical value, if the theory of inflation is wrong.
(I see no reason to think it is.)
Presumably the 10^-40 has something to do with the balance
of matter and antimatter. I am not convinced that there's
any real fine-tuning there, though; since matter and antimatter
annihilate one another on contact, any asymmetry (large or
small) between the two is liable to turn into a near-absence
of one.
Then there are other finely tuned factors so that the elements needed
for life could be formed.
So when you put it all together, it suggests there must be intelligent
design involved.
Suggesting something and providing actual evidence for it
are not the same.
--
Gareth McCaughan
sig under construc
.
- Follow-Ups:
- Re: big bang problems
- From: marcandmia
- Re: big bang problems
- References:
- big bang problems
- From: marcandmia
- big bang problems
- Prev by Date: Re: big bang problems
- Next by Date: Re: calls for sunday legislation
- Previous by thread: Re: big bang problems
- Next by thread: Re: big bang problems
- Index(es):
Relevant Pages
|
