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Cosmic inflation preceded the Big Bang (bigthink.com)
41 points by the__prestige 11 days ago | hide | past | favorite | 24 comments





You know, a non-trivial amount of the distrust in science comes from science publications that find some fringe theory, even respectable fringe theories like this one, and then publish articles about how they're 100% right and imbued with the full confidence of science.

It's an interesting article, but the tone is terribly wrong.


I am 100% sure those kind of articles contribute nothing to distrust in science. I bet you a $100 the people who are anti science never read article like that.

Dipping toes in flat earth community, when I still believed that its largely a 'for the lulz' community, there are predictable patters of how those are formed and propagated/sustained.

There are few opinion makers that use techno/science babble to create theories that have easy to grasp headline so it easily spreads as a meme in the community.

I strongly believe vast majority of those people are scams, selling books to their followers. But their followers dont read anything but their own post,headlines, materials. All easy reads exposing some secret knowledge kept from the people.

In fact those communities are almost identical to religions, only their dogmas are still shifting, forming, spliting and evolving. But one universal mechanism for all is conformity to the dogma, any outsider get shutdown as an enemy and their ideas gets thrown away.


They said "distrust in science", not "anti-science". Those are two entirely different things.

Speaking as an American, most Americans see "science" in the news media and assume it's 1.) accurate and 2.) actual science, and then it turns out to be fringe, or the media got it entirely wrong and it gets stored in these people's personal caches of "How scientists are always wrong." Eg. the American debate on climate change.


I endorse this reply.

I'm thinking not "flat earth" here, but people who are legitimately exhausted from the scientific media telling them eggs are good for you one month, and then that they're bad for you the month, and repeating that for literally decades.

It is a rational conclusion to devalue science, or at least devalue science journalism, at that point. Science journalism should not be so free in giving people rational reasons to discount them.


I like how singluarity and inflation are the only things that could have possibly occurred prior to the big bang, turning evidence against one option into definitive proof of the other.

> fringe theories like this one

How do you define "fringe theory"? I'm pretty sure inflation has been the mainstream view among cosmologists since the 1980s.


I think the “fringe” comes from the theory that cosmic inflation occurred before the BB

Nothing fringe about it, it's a general feature of inflation models. Exponential expansion essentially quick-freezes the universe, until the field which drives it (the inflaton) decays. At that point, exponential expansion stops (so no more cooling) and the universe fills with a hot soup of decay products. It's called reheating, and plays the role of old-school big bang:

https://en.wikipedia.org/wiki/Inflation_(cosmology)#Reheatin...


For most theories, it is relatively easy to find parts that should be removed because they either are erroneous or there is no evidence for them, but it is always much harder to find something else that is better and that could substitute the wrong parts.

The author correctly notices that it is a mistake to extrapolate the Big Bang theory too far, because from some point there is no more evidence for what happened before.

After this correct observation, then the author proceeds with a hypothesis about a prior "inflation", for which there is also no evidence, like for the more traditional Big Bang variants that are criticized.

I believe that it is necessary to always make a clear distinction between facts that are reasonably certain and facts that are just wild hypotheses, which are interesting to discuss, but for which there exists no information that could either confirm or refute them.

What we know with reasonable certainty is that the composition and evolution of the observable universe can be explained very convincingly if it started from an initial state of very high temperature, equivalent with a kinetic energy per particle of several tens of megaelectronvolt, i.e. higher than the binding energy of atomic nuclei.

At this temperature, the matter consisted of a plasma containing free protons, neutrons, electrons and positrons (plus neutrinos and photons).

There were equal numbers of protons and neutrons (i.e. equal numbers of u and d quarks) and slightly more electrons than positrons, the excess being enough to make the plasma electrically neutral.

At this stage, besides the very high temperature, the average density was also much higher than today. The matter composing the currently observable universe would have been concentrated in a much smaller space than today, but that space would have been huge nonetheless.

There is no evidence whatsoever about what might have happened before this stage.

The popular presentations of the Big Bang theory assume that before this stage there were even higher temperatures and densities.

This hypothesis might seem more satisfying intellectually, i.e. that everything might have started from a point, but it must be clear that there is no reason to believe this, except personal preferences about what to believe when there is no information about something.

If we extrapolate backwards to higher temperatures, the plasma composition becomes more and more complex, first it also includes pions and muons and then more and more kinds of particles that are normally unstable. After some point, we no longer can predict anything with reasonable accuracy. We must not forget that the current physics cannot predict simple things like the mass ratios between nuclei or the atomic spectra, so expecting a good model for a state of matter for which we do not have any experimental data would be naive.

Maybe before the known initial state there were indeed higher temperature and density states as in the popular Big Bang presentations and the Universe cooled to reach that state, but maybe the earlier temperatures were lower and something increased the temperature, like the author of the article supposes.

We do not know anything that might have heated the Universe, but if the Universe was previously hotter we also do not know anything that could have provided the initial energy and we do not know how matter would behave at those higher temperatures and densities.

So either way we exit the domain of quantitative models that can be fitted to match what we see around us and we enter the domain of speculations, which might be or not be of any use.


A lot of wonder and imagination is also inspired by fringe ideas. I’m not going to be so puritan about things.. leave that for the journals.

Is it possible that there are no singularities, even in black holes? Could there be another type of degeneracy pressure (after electrons and neutrons) that permits matter to compress enough to form an event horizon, but not a true singularity/ringularity? I know this is a poorly-understood area of physics but I'm curious if this particular possibility has been ruled out, and if it would have any relevance to BBT and cosmic inflation if it were found to be true.

Sure. A singularity is your theory crashing with a "not applicable in this regime" error. It means you need a better theory, in this case of how gravity behaves at high energy density. One possible take on it is fuzzballs:

https://en.wikipedia.org/wiki/Fuzzball_(string_theory)


  > A singularity is your theory crashing with a "not applicable in this regime" error.
Sometimes I tell myself that I read HN for the articles. But what I'm really after is elegance like this. Thank you.

Tsk, tsk. Not a single mention of Roger Penrose's Conformal Cyclic Cosmology.

https://en.wikipedia.org/wiki/Conformal_cyclic_cosmology


Which is far cooler, and comes from a far more credible scientist, though as a notion, still requires low credence.

Penrose has far more insight into the mathematics of the beginning and ending of the universe than your average genius-cosmologist. Yet claims for supporting data from CMB analysis (residual cold-spots from black holes in past epochs) should have been confirmed by now. So far as I know, those results haven't been repeated and all occur within error margins.


Does anyone have any books they'd recommend on the topic of the Big Bang?

The Big Bang theory has always seemed dissatisfying to me, like there's some prima facie aspects of it that defy logic, or are "just so" in quality. It's always seemed to me to be the sort of thing that will eventually be superceded by some more complete explanation; that is, the Big Bang is correct but is part of a bigger story.


From Eternity to Here by Sean Carroll is a worthwhile read.

The book isn't particularly about the Big Bang (it's more about the nature of the arrow of time), but it has to deal with the subject in passing.

I can also recommend the video series The Biggest Ideas in the Universe [1]. These are a superb explanation of how modern science has arrived at the conclusions it has. You can jump ahead to the Cosmology video, if you must, but you're missing the full experience of building up an understanding that goes far beyond the usual crayon drawings the press gives us.

[1] https://www.youtube.com/playlist?list=PLrxfgDEc2NxZJcWcrxH3j...


Seconding Carroll's "Biggest Ideas" as hard as I can. Really a fantastic gift to the world. Make sure you don't miss the Q&A videos; there's one for each regular installment, about equal in length and content, and in addition to clarification he'll discuss more speculative ideas and some very interesting tangents for each subject.

No book to recommend, but i've been watching the Closer To Truth channel on YouTube which interviews scientists, astronomers, and cosmologists. Quite fascinating to hear so many views on what is the universe

This article does a remarkably poor job of explaining what cosmic inflation is. I gave up halfway through when I realized it was never going to explain to me how "inflation" is different from "expansion."

Inflation theory has been around since the 70s.

<https://en.wikipedia.org/wiki/Inflation_(cosmology)>


Please no more economic news...

The title would have been related to economic news if we were living in the world of Rick and Morty. I get how it can be misleading though.

- and that's how ladies and gents, you fake knowing economics

P.S. the article is not related to economics


I had written something else entirely and edited it and then forgot to remove the last bit. Apologies for the terribly useless comment.



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