Inflated Expectations: a Cosmological Tale by Burton Howard;
Author:Burton, Howard;
Language: eng
Format: epub
Tags: Physics, Cosmology, Astrophysics, Philosophy
Publisher: Open Agenda Publishing
Published: 2020-10-02T00:00:00+00:00
Questions for Discussion:
What does it mean, exactly, for a field to be âfine-tunedâ and what would a âsolutionâ to the associated âfine-tuning problemâ look like in principle?
To what extent might a âfine-tuning problemâ be âsolvedâ by invoking the anthropic principle?
What do you think Paul means, exactly, when he talks about âseparating this degeneracyâ?
IV. Two Major Issues
The initial value problem and eternal inflation
HB: And while this was going on, your thoughts on inflation as a principleâstandard inflationary cosmologyâare moving in what direction? What other concerns did you have?
PS: Well, shortly after inflation was developed, two big issues arose. Fine-tuning was not one of these first big twoâIâm putting that as a third issueâso although thatâs the one that most people spend their time on, thatâs not one of the real problems, in my view.
The two big problems are:
First, we didnât properly think through how inflation gets started. What we said is, âIf you have some random distribution of matter and energy coming out of The Big Bang, inflation will smooth it out.â But we began with, âIf you have inflationâ¦â
Well, what does the inflation need? It turns out the inflation needs a universe which is rather smooth and flat to begin with, which was the very thing inflation was supposed to be doing for you.
And it needs it to be smooth and flat over a fairly large scaleâlarger than the size of the horizon, the largest distance that you could see at the time. So it has to occur over a scale in which normal, physical processes wouldnât be able to interact. This is what we sometimes call the âinitial conditions problemâ: we donât know how to initiate inflation.
That is, instead of it taking over easily, inflation can only take over if someone has already smoothed out the universe to a significant degree, which solves the problem that we wanted to solve to begin with.
Suppose we say that, coming out of the Big Bang, thatâs very unlikely but itâs not impossible. It could be by chance that it came out that way. It seems like it requires a conspiracy over large scales, so itâs very, very unlikely. But itâs possible. Thatâs true. But, as unlikely as that is, it turns out that the condition you need to start inflation is exponentially more special, more unlikely.
So in order to explain your first unlikeliness, youâve actually had to go to a situation which is exponentially more unlikely.
That was first pointed out by Roger Penrose using a very clever but subtle argument; and then, over the decades, other arguments have been developed.
HB: Wasnât it 10 to the 10100 or something crazy like that?
PS: Yes, I like to describe it as the worst prediction ever. Youâre trying to explain why we are the way we are by following this line of argument, and by using the statistical measure he proposedâwhich turns out to agree with other ways of doing the estimateâyou end up saying, Weâre only likely as one part in 10 to the 10100, as an upper bound.
Download
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.
The Complete Stick Figure Physics Tutorials by Allen Sarah(7109)
Secrets of Antigravity Propulsion: Tesla, UFOs, and Classified Aerospace Technology by Ph.D. Paul A. Laviolette(4883)
Thing Explainer by Randall Munroe(3761)
The River of Consciousness by Oliver Sacks(3388)
The Order of Time by Carlo Rovelli(3061)
How To by Randall Munroe(2901)
I Live in the Future & Here's How It Works by Nick Bilton(2824)
A Brief History of Time by Stephen Hawking(2804)
What If?: Serious Scientific Answers to Absurd Hypothetical Questions by Randall Munroe(2533)
The Great Unknown by Marcus du Sautoy(2521)
Blockchain: Ultimate Step By Step Guide To Understanding Blockchain Technology, Bitcoin Creation, and the future of Money (Novice to Expert) by Keizer Söze(2369)
Midnight in Chernobyl by Adam Higginbotham(2369)
Networks: An Introduction by Newman Mark(2250)
The Meaning of it All by Richard Feynman(2198)
Easy Electronics by Charles Platt(2191)
The Tao of Physics by Fritjof Capra(2152)
Midnight in Chernobyl: The Untold Story of the World's Greatest Nuclear Disaster by Adam Higginbotham(2062)
When by Daniel H Pink(2011)
Introducing Relativity by Bruce Bassett(2004)
