(Nov 28, 2023 02:56 AM)Syne Wrote: (Nov 25, 2023 06:57 PM)C C Wrote: Cosmic inflation preceded the Big Bang
https://bigthink.com/starts-with-a-bang/...g-universe
You've cited this idea several times, but it really seems like someone was biased by their dislike of singularities and completely invert the order of events widely agreed upon:
In physical cosmology, cosmic inflation, cosmological inflation, or just inflation, is a theory of exponential expansion of space in the early universe. The inflationary epoch is believed to have lasted from 10−36 seconds to between 10−33 and 10−32 seconds after the Big Bang.
- https://en.wikipedia.org/wiki/Inflation_(cosmology)
Just claiming inflation preceded the big bang doesn't make it so. [...] So it seems this astrophysicist "science communicator" isn't up to the task.
Siegel isn't the source of that view. Guth himself asserts inflation preceded the conventional expansion of the universe called the "Big Bang" (hot BB and the "era" of BB distinction). But not the other usage of BB that has arisen to keep the term in play, where "Big Bang" refers to the universe's yet earlier stage of origin. Grinin's extended analysis further down is one of the few attempts to sort out the semantic mess that has transpired since cosmological inflation was accepted by the majority. This language politics being beside the point or issue of whether any proposal is actually the case or not.
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Leonid Grinin: As we have seen from the above discussion, the stage of the hot Big Bang succeeded the post-inflationary heating stage. However, there are still a number of scientists who, just as before, consider the Big Bang as the moment of the origin of the Universe followed by inflation. [Guth refers also refers to the secondary meaning, further below.] However, this disagreement can be explained not only by differences in points of view but also by the confusion in terminology. The question is that when speaking about the Big Bang as an event preceding the beginning of inflation, it is often meant not the hot Big Bang (i.e., classical Big Bang), but another one, i.e. the pre-inflation Big Bang.
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Will Kinney interview -
Cosmic Inflation and the Beginning of the Universe
https://www.buffalo.edu/news/releases/2022/03/033.html
"Prior to the Big Bang — yes, before the Big Bang — the universe underwent a breathtaking cosmic expansion, doubling in size at least 80 times in a fraction of a second."
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NASA -
What is the Inflation Theory?
https://wmap.gsfc.nasa.gov/universe/bb_cosmo_infl.html
"The Inflation Theory [...] offers solutions to these problems and several other open questions in cosmology. It proposes a period of extremely rapid (exponential) expansion of the universe
prior to the more gradual Big Bang expansion..."
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Alan Guth on new insights into the Big Bang
https://news.mit.edu/3-q-alan-guth-on-ne...e-big-bang
Alan Guth: "At some point the inflation ends because the repulsive-gravity material becomes metastable. The repulsive-gravity material decays into ordinary particles, producing a very hot soup of particles that form the starting point of the conventional Big Bang. At this point the repulsive gravity turns off, but the region continues to expand in a coasting pattern for billions of years to come. Thus,
inflation is a prequel to the era that cosmologists call the Big Bang, although it of course occurred after the origin of the universe,
which is often also called the Big Bang."
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Conceptual politics in science: The confusion of "Big Bang" usage in contempoary cosmology discourse
Was there a Big Bang? (Leonid Grinin)
https://puncta.journals.villanova.edu/in.../2339/2266
EXCERPT: As we have seen from the above discussion, the stage of the hot Big Bang succeeded the post-inflationary heating stage. However, there are still a number of scientists who, just as before, consider the Big Bang as the moment of the origin of the Universe followed by inflation. However, this disagreement can be explained not only by differences in points of view but also by the confusion in terminology. The question is that when speaking about the Big Bang as an event preceding the beginning of inflation, it is often meant not the hot Big Bang (i.e., classical Big Bang), but another one, i.e. the pre-inflation Big Bang.
Thus, today speaking about the Big Bang, it is necessary to specify which explosion is mentioned. The fact is that there is no common terminology concerning the Big Bang in physics and cosmology, which study the early Universe: there is considerable confusion here.
Sometimes the followers of the Inflation theory mention the Bang that preceded the inflation stage. They might regard this bang as above mentioned quantum fluctuation or another hypothetical event of uncertain origin. Sometimes they talk about such Big Bang as a special phase of early history of the Universe.
Unfortunately they do not clarify whether this Big Bang was the trigger for the quantum fluctuation, or it is just the beginning of the inflationary stage. In any case this Big Bang was definitely cold but not hot. However, some researchers do not identify the pre-inflation cold Big Bang or do not mark it out as a special stage because such a variety in approaches implicitly creates a great confusion in our understanding of the notion of the Big Bang.
Were there two Big Bangs or was only one or none at all? And after what stage it occurred? The confusion is growing because the Big Bang theory also implies the inflationary stage. But the sequence of stages differs from that of the Inflation theory.
According to the Big Bang theory, the Big Bang was the first to occur and led to great inflation.
And the Inflation theory suggests that the hot Big Bang resulted from the inflation.
As we will see below, such a shift of the processes’ order makes the Big Bang unnecessary stage in the sequence of events that occurred in the Universe. One should also note that not all researchers distinguish the stage of post- inflationary heating. As a result this situation seems paradoxical. On the one hand, practically, there are no scientists who would definitely reject the Big Bang.
On the other hand, a number of researchers who use this concept as something conventional, but indefinite, increases.it appears that implicitly or even explicitly they understand that the theory can easily avoid using the Big Bang notion. However, because the direct negation of the Big Bang may cause difficulties, probably they think that the best way to avoid problems is the indistinct mentioning of this moment.
Thus, one should mention that the Big Bang seems to become a kind of metaphor, an indicator of fidelity to the mainstream, playing a role similar to that of the incomprehensible god in deism philosophy. We recall that the situation is greatly complicated.
Among many followers of the Inflation theory there is an implicit assumption that there could be two trigger events which can be described as ‘bangs’, one of which preceded the inflation, and the other – followed it.
But the description and characteristics of the preinflation Big Bang are even more obscure than those of the hot Big Bang. It also does not have any common term; there are references to the Planck era of the Big Bang, the early Big Bang stage, the real Big Bang, etc.
One should mention that due to this terminological and theoretical confusion it is extremely difficult to understand whether one or two explosions are meant, as well as to describe the real sequence of stages.
If there were two Big Bangs then the origin of the Universe would schematically look like this: the preinflationary Big Bang – inflation (expansion of the Universe) – post-inflationary heating of the Universe – the hot Big Bang. But such a reconstruction is not presented anywhere because perhaps as was mentioned above it is easier to avoid difficulties. Most commonly mentioning of the Big Bang among physicists simply looks like a tribute to a tradition they dare not to violate, and therefore such mentions are rather ritual than filled with specific content.
In general, it appears that the early history of the Universe may well do without using the concept of the Big Bang, using the scheme: fluctuation (whatever it may have been caused by) – inflation – post-inflationary heating.
Thus, among a large number of astrophysicists the very idea of the Big Bang has been losing not only its substantiality and uniqueness, but the need in general. However, at the same time among others and especially among those who popularizes the early history of the Universe one can observe dominating desire to see something extremely real and apocalyptic in the Big Bang.
Perhaps, it would be too strong to call the Big Bang ‘a misleading, ugly and trivializing name’. (as Timothy Ferris did; see Wood 2018: 2).
Nevertheless in the light of modern points of view it is very necessary to regard the Big Bang not as a real huge explosion but rather as a metaphor that still exists due to tradition. The matter is that ‘the Big Bang, just as we imagined it traditionally, most likely did not occur at all’ (Mukhanov and Orlova 2006). At the same time, most initial conditions that determine the most important characteristics of the modern Universe are also referred to the inflationary stage, rather than the hot Big Bang.
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What Came First: Inflation Or The Big Bang?
https://www.forbes.com/sites/startswitha...1862314153
Ethan Siegel: We do not know where the inflationary state came from, however. It might arise from a pre-existing state that does have a singularity, it might have existed in its inflationary form forever, or the Universe itself might even be cyclical in nature.
There are a lot of people who mean "the initial singularity" when they say "the Big Bang," and to those people, I say it's long past due for you to get with the times. The hot Big Bang cannot be extrapolated back to a singularity, but only to the end of an inflationary state that preceded it. We cannot state with any confidence,
because there are no signatures of it even in principle, what preceded the very end-stages of inflation. Was there a singularity? Maybe, but even if so, it doesn't have anything to do with the Big Bang.
Inflation came first, and its end heralded the arrival of the Big Bang. There are still those who disagree, but they're now nearly a full 40 years out of date. When they assert that "the Big Bang was the beginning," you'll know why cosmic inflation actually came first. As far as what came before the final fraction-of-a-second of inflation? Your hypothesis is just as good as anyone's.
Nov 28, 2023 02:56 AM
(This post was last modified: Nov 28, 2023 03:19 AM by Syne.)
