[Marxism] The Big Bang Theory
pgallagher4 at gmail.com
Fri Jun 27 19:20:23 MDT 2008
Why do you think what you quote puts the Big Bang in doubt, or that alternatives
to the Big Bang are being presented?
The Big Bang - the idea of an expanding universe - is well supported by many
kinds of evidence. This gives rise to many open questions, such as why
seems flat, homogenous, and isotropic, and why there are large scale
structures in the
universe. Guth proposed early cosmic inflation resulting from negative-pressure
vacuum energy to account for these features or apparent features of
What's in dispute here is this early rapid expansion of the universe -
cosmic inflation -
and that is where rival models employing string theory and branes
enter. Expansion itself -
the Big Bang - is not in dispute.
On Fri, Jun 27, 2008 at 6:12 PM, Les Schaffer <schaffer at optonline.net> wrote:
> the evidence isnt there to distinguish between the two theories, i
> heartily agree. my point was there is more than one *theory* that can
> account for large scale observational features. things have changed
> since Big Bang was the only thing one could talk about.
> but if you take your argument one step further, we need not accept the
> Big Bang as proven, because a key ingredient -- inflation -- is an
> unproven hypothesis. i am ok with that too. yes, talking about vacuum
> energy is a lot more solid at this point than talking about branes. but
> i don't see your razor as that sharp.
> and later you write:
>> Disagree all you want, but no other testable theory accounts for the
>> expansion of the universe and the background radiation.
> Look thru Guth and see if you can find such a "testable" claim. for
> others, here is how Guth (the first author on inflation) concludes his
> summary of inflation to date (2007):
> We should keep in mind, however, that observations in the past few
> years have
> vastly improved our knowledge of the early universe, and that these
> new observations
> have been generally consistent with the simplest inflationary
> models. It is the success
> of these predictions that justifies spending time on the more
> speculative aspects of
> inflationary cosmology.
> i was going to ask if chegitz could prove the inflaton exists. but on
> checking this thought first, i came across a paper entitled "Inflation
> without Inflaton(s)". here is their opening paragraph
> Despite the simplicity and promising phenomenology of scalar driven,
> slow-roll inflation,
> much remains to make the idea theoretically viable. In particular,
> vexing issues such as the required
> flatness of the inflationary potential and the very existence of a
> fundamental scalar (which must
> be both extremely light and weakly interacting) remain elusive (see
> however [1, 2, 3]). In recent
> years, a substantial effort has been invested in understanding how
> to embed such models in a quantum
> theory of gravity [6, 7], and there has also been the suggestion of
> removing the need for slowroll
> completely  (see  for earlier work). However, in this paper we
> will take a different and yet
> complimentary approach to inflation model building based on
> fundamental scalars.
> the point is, things are a wee bit more open than chegitz lets on, So i
> find chegitz's take a little too bombastic. but i side with him over
> Yossi's view.
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