# Big Bang
**URL:** https://boards.straightdope.com/t/big-bang/177512
**Category:** Factual Questions
**Created:** [May 26, 2003, 2:07am UTC](https://boards.straightdope.com/t/big-bang/177512 "2003-05-26T02:07:48Z")
**Posts on this page:** 13
**Page:** 1
### Author:  [@Major\_Kong](https://boards.straightdope.com/u/Major_Kong)
#### Post date: [May 26, 2003, 2:07am UTC](https://boards.straightdope.com/t/big-bang/177512/1 "2003-05-26T02:07:48Z")
Is Big Bang the correct the name? Is this what scientists call this event?
How accepted is this theory?
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### Author:  [@MLS](https://boards.straightdope.com/u/MLS)
#### Post date: [May 26, 2003, 2:21am UTC](https://boards.straightdope.com/t/big-bang/177512/2 "2003-05-26T02:21:33Z")
Yes. Yes. Widely.
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### Author:  [@Marley23](https://boards.straightdope.com/u/Marley23)
#### Post date: [May 26, 2003, 2:48am UTC](https://boards.straightdope.com/t/big-bang/177512/3 "2003-05-26T02:48:27Z")
I don’t think it’s a stretch to say it’s completely accepted - among those with credibility. No serious challenge or competing theory has arisen.
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### Author:  [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)
#### Post date: [May 26, 2003, 3:15am UTC](https://boards.straightdope.com/t/big-bang/177512/4 "2003-05-26T03:15:17Z")
Technically speaking, inflation has replaced the big bang as the accepted understanding of the beginning of the universe.
The difference is that the Big Bang is usually presented as an explosion _in_ space. Inflation takes space itself and expands it a phenomenal amount.
And yes, there are no serious competitors to inflation right now. Although there will always be some hungry young scientist out to make his name by coming up with a wild new idea that will try to explain away any points left that are unclear.
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### Author:  [@AncientHumanoid](https://boards.straightdope.com/u/AncientHumanoid)
#### Post date: [May 26, 2003, 3:30am UTC](https://boards.straightdope.com/t/big-bang/177512/5 "2003-05-26T03:30:17Z")
“Big Bang” was originally coined as a derisve name for this theory by “Steady State” adherents. Fred Hoyle, I believe, was the first to use it. then it just caught on.
I’ll try to find a link…
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### Author:  [@Rabid\_Squirrel](https://boards.straightdope.com/u/Rabid_Squirrel)
#### Post date: [May 26, 2003, 3:30am UTC](https://boards.straightdope.com/t/big-bang/177512/6 "2003-05-26T03:30:53Z")
Yeap, there will always be disagreement and new theories, but isn’t that what science is all about?
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### Author:  [@AncientHumanoid](https://boards.straightdope.com/u/AncientHumanoid)
#### Post date: [May 26, 2003, 3:44am UTC](https://boards.straightdope.com/t/big-bang/177512/7 "2003-05-26T03:44:04Z")
[Big Bang FAQs](http://www.astro.ucla.edu/~wright/cosmology_faq.html)
[Hoyle and “Big Bang”](http://news.bbc.co.uk/1/hi/uk/1503721.stm)
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### Author:  [@bonzer](https://boards.straightdope.com/u/bonzer)
#### Post date: [May 26, 2003, 12:14pm UTC](https://boards.straightdope.com/t/big-bang/177512/8 "2003-05-26T12:14:10Z")
To be more specific, Hoyle first used the term in a BBC radio broadcast in 1949, the text of which was reprinted as _The Nature of the Universe_ the following year.
> [@](#):
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> On scientific grounds this big bang assumption is much the less palatable of the two … On philosophical grounds too I cannot see any good reason for preferring the big bang idea.
This is the passage in question as quoted by Kragh in _Cosmology and Controversy_ (Princeton, 1996; 1999, p192). Kragh goes on to note that, while the radio talks and the book were phenomenally successful, it took a while for the term “Big Bang” to become adopted as the technical term. It’s worth noting that none of Gamow, Alpher and Herman, the ones who’d come up with the model Hoyle was referring to, ever liked the term (p120).
A few years back _Sky and Telescope_ magazine ran a competition to find an alternative. I can’t remember what the better suggestions were, but there was a concensus that none were quite as snappy or memorable as Hoyle’s.
> [@](#):
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> \*Originally posted by Exapno Mapcase \*
> The difference is that the Big Bang is usually presented as an explosion _in_ space. Inflation takes space itself and expands it a phenomenal amount.
Depends on who’s doing the presenting.
When being precise, the professionals tend to distinguish between the “hot Big Bang model” (or similar, Kolb and Turner use “Standard Cosmology” for the same model) and inflationary models as applying at different times in the expansion. The latter complement the former rather than replace it.
The whole set of events is, somewhat more loosely, still referred to as the Big Bang.
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### Author:  [@rsa](https://boards.straightdope.com/u/rsa)
#### Post date: [May 26, 2003, 1:19pm UTC](https://boards.straightdope.com/t/big-bang/177512/9 "2003-05-26T13:19:27Z")
IOWs,
1. Big Bang
2. Inflation
They are not exclusive.
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### Author:  [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)
#### Post date: [May 26, 2003, 4:35pm UTC](https://boards.straightdope.com/t/big-bang/177512/10 "2003-05-26T16:35:01Z")
Scientists are just as loose in their use of English as anyone else. The Big Bang is a term too entrenched – and way too colorful – to be replaced by something as drab as inflation.
Still, if you look at the chart in the link by **NoClueBoy** you’ll see that it is not the belief anymore that the universe began with a giant explosion. Everybody thinks that the universe came into being very quietly and then after a brief but measurable amount of time inflated enormously. There are consequences to the two notions and everything we know today points to inflation and not a giant explosion at the beginning as the better explanation. Even all popular discussions of the beginning will give the inflationary model and not a Big Bang one.
Big Bang and Inflation are technically exclusive. But they’re close enough so that the term Big Bang won’t be going away any time soon.
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### Author:  [@bonzer](https://boards.straightdope.com/u/bonzer)
#### Post date: [May 28, 2003, 12:01am UTC](https://boards.straightdope.com/t/big-bang/177512/11 "2003-05-28T00:01:13Z")
> [@](#):
>
> \*Originally posted by Exapno Mapcase \*
> Big Bang and Inflation are technically exclusive.
Nope. At least not without using an unnecessarily narrow definition of inflation. What you’re saying applies to certain varieties of inflation, but that’s about it.
As [an example](http://nedwww.ipac.caltech.edu/level5/Liddle/Liddle4.htm) from a distinguished theorist of inflation:
> [@](#):
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> Inflation does not replace the hot big bang theory; it is a bolt-on accessory attached at early times to improve the performance of the theory.
or [from here](http://www.astro.ucla.edu/~wright/glossary.html):
> [@](#):
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> **inflationary scenario** : a modification of the Big Bang model in which a large cosmological constant exists temporarily early in the history of the Big Bang, leading to a rapid accelerating expansion of the Universe, which is then followed by the normal Big Bang model with a decelerating expansion.
As I’ve already noted, physicists and cosmologists are quite careful in referring to the “hot Big Bang model”. This applies to the behaviour of the universe after, at most, 10[sup]-2[/sup] seconds after the “beginning”. It involves a universe that is previously expanding, at extremely high temperature and in thermal equilbrium. This is completely accepted.
The big open question is how did the universe reach such a state at 10[sup]-2[/sup] seconds? Or rather, that plus a few more technical questions. In the 1980s Alan Guth proposed that these questions could be answered by _inflation_, a period early in the Big Bang where the universe behaved as a de Sitter model and expanded exponentially. That such a period occured is broadly accepted; why it happened less so. As a result, when physicists refer to the “hot Big Bang model” they mean whatever happened after 10[sup]-2[/sup] seconds. Inflation is the period somewhat before this and inflationary models describe this earlier time. The two types of models are thus entirely complementary. You have inflation and then you have a Big Bang.
In Guth’s version, inflation was however merely an interlude in the Big Bang. A very hot universe was cooling, to the point where it passed through a phase transition, which caused it to inflate. Historically, the idea passed through various versions. Then Andre Linde hit on the notion of _chaotic inflation_. The crucial technical twist was that this didn’t require a large temperature.
As I recall from the arguments at the time, Linde’s initial idea was framed very much in terms of, at least, a Bang. A spacetime would somehow pop into existance via a quantum fluctuation with a radius of about about a Planck length and then inflate to the sort of universe we see. A sort of Gentle Bang becoming a Big one via inflation.
Then people hit on _eternal inflation_. This is usually coupled with the chaotic variety, though can be tied to other models. The idea is that if inflation needn’t be associated with extreme conditions, perhaps it’s happening in “everyday” universes. Like ours. It’s only at this point that people, notably Linde, try to cut inflation free from a Big Bang. Perhaps a normal universe can give rise to other universes that look new. As an example of this attitude, [here’s his _Scientific American_](http://physics.stanford.edu/linde/1032226.pdf) article on the subject. Or [a more recent review of his](http://moriond.in2p3.fr/J00/ProcMJ2000/linde/paper.pdf). In such a view there isn’t “a” Big Bang.
Aside from philosophical prejudices, there are technical objections - primarily the fact that it doesn’t appear to avoid an initial (and hence hot) singularity.
“Chaotic inflation” is undoubtedly the most popular variety on the table. But nobody pretends it’s the unquestionable version. Nor is “eternal inflation” the obvious choice for a version of it.
As for more colloquial usages, [here’s Steven Weinberg on chaotic inflation](http://home.earthlink.net/~kslinker/designer_universe.htm):
> [@](#):
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> According to the “chaotic inflation” theories of André Linde and others, the expanding cloud of billions of galaxies that we call the big bang may be just one fragment of a much larger universe in which big bangs go off all the time, each one with different values for the fundamental constants.
He may be writing for the _NYRB_ rather than _Phys.Rev.Lett._, but it’s a good example of how someone can still refer to big bangs in the context of chaotic inflation, even though Linde thinks the concepts are completely different.
> [@](#):
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> Even all popular discussions of the beginning will give the inflationary model and not a Big Bang one.
Perhaps. And so long as they just restrict such discussions to “the beginning” before 10[sup]-2[/sup] s they might even be right.
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### Author:  [@Ring](https://boards.straightdope.com/u/Ring)
#### Post date: [May 28, 2003, 3:55am UTC](https://boards.straightdope.com/t/big-bang/177512/12 "2003-05-28T03:55:45Z")
> [@](#):
>
> \*Originally posted by Exapno Mapcase \*
> \*\*
> The difference is that the Big Bang is usually presented as an explosion _in_ space. Inflation takes space itself and expands it a phenomenal amount.
> \*\*
The big bang is certainly not and never has been an explosion _in_ space.
With or without inflation the big bang always has been considered as _creating_ both space and time. Prior to the BB the only thing in existence was absolutely nothing.
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### Author:  [@Swagman](https://boards.straightdope.com/u/Swagman)
#### Post date: [May 28, 2003, 5:10am UTC](https://boards.straightdope.com/t/big-bang/177512/13 "2003-05-28T05:10:41Z")
For an alternative view and one that makes a great deal more sense than the Big bang Theory take a look at [http://www.holoscience.com/eu/synopsis/4.bigbang.html](http://www.holoscience.com/eu/synopsis/4.bigbang.html)