Inflation Definition and 399 Threads

I write this in the hope that somebody reading this can explain to me, a laymen, in non-mathematical, plain English terms, why my thinking is wrong regarding the calculation of the age of the observable Universe and the formation of the elements in the Periodic Table given the (short) age of...

-In the first few fractions of a second after the big bang, was the universe finite and closed during early inflation, before it smoothed out and became flat and infinite? I am wondering because I would like to know if the theory implies that the universe initially inflated with a finite...

] arXiv:1310.2072 [pdf, ps, other] Intermediate inflation from rainbow gravity John D. Barrow, Joao Magueijo Subjects: Cosmology and Extragalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc) It is possible to dualize theories based on deformed dispersion...

I've heard people say that a 4.0 GPA can look a bit suspicious to admissions committees for grad school. I'm wondering how true this actually is... I assume it depends greatly on whether the 4.0 is coming from a well known university. Let's say that the 4.0 is just coming from a large state...

I was looking at the wikipedia article about cosmic inflation (you know, the first 10-32 seconds). It says that an inflation hypothesis is a neat way to explain a number of otherwise puzzling observations, but it doesn't say much about what would make inflation occur and it doesn't mention...

I was thinking that "eternal inflation" model deals nicely with the problem of the beginning of the universe. If I understand this model correctly, Multiverse is a boiling bulk of some sort of very dense vacuum, creating inflationary "bubbles" (baby Universes), finite from the outside but...

Assuming that the early inflation of the universe is driven by the potential energy of some inflaton field(s), the "normal" matter is created only after this rapid inflation has stopped by conversion of the latent energy of the corresponding phase transition to particles. Does this mean that...

according inflation, the universe should to be uniform in all directions at large scale, but observations from the Planck spacecraft found fluctuations in the cosmic microwave background that undermines the model. http://www.kavlifoundation.org/science-spotlights/kicc-planck-universe

Blackforest asked about an interesting paper recently posted by G.F.R. Ellis, that MTd2 spotted and added to our bibliography. I hope we can have some discussion of the Ellis paper. Unimodular gravity is a variant of the usual GR which is restricted to metrics which do not feel "vacuum...

There's a belief floating around that it takes "jumping through a lot of hoops" for a theoretical model to predict inflation AND give an adequate amount AND then stop . The conventional wisdom is it requires fine-tuning for inflation to turn on, go for at least 60 efolds, and then turn off, i.e...

It is often said that although the expansion of the universe may create the illusion of objects in very far regions of the universe to recede from each other at superluminal speed, that does not violate c because locally they never move faster than c. This I can understand. How would things...

Hello, In the early stages of Cosmic Inflation, immediately after the Big Bang, all matter was basically energy in a plasma form. It continued to expand for 380,000 years before cooling enough to form the first atoms. I have two questions: 1. Did this matter continue to exist in a...

I've been haqving a tough time tracking down which particular inflationary models form the basis of \LambdaCDM. the model I have discounted already is false vacuum A.Guth. some articles seem to suggest concepts from slow roll inflation. Others deal specifically with the inflaton field in...

Was it inflation that started off the universe to exist, or was it the Big Bang? The reason I ask is because from I've read is that the universe wasn't an explosion, but rather a rapid expansion. Was there a small explosion we call the big bang, then the cosmological inflation? Or was there...

Hi, I've been reading about inflation, and I'm not totally convinced about how it is proposed to result in a flat universe. If I understand it correctly, inflation expanded the universe so rapidly that the actual size of the universe now is 23 orders of magnitude larger than the observable...

Slides and audio for this talk by Brajesh Gupt were posted online today. LQC bounce creates conditions for inflation. It's important to extend the quantum bounce model to anistropic cases, such as Bianchi I. Anisotropy can affect what one expects from the ensuing inflationary episode. Here...

Was it gravity? Does the expansion of the universe have anything to do with the original inflation? One more. What actually is the "fabric" of space that is expanding? You always hear the balloon analogy, so what makes up the rubber of the balloon in real life? Thanks in advance for my...

I figure that we need a thread specifically for this topic, while we try to sort out just how minimal physics could be, in the wake of the Moriond conference on the Higgs and the data release from the Planck collaboration. Fedor Bezrukov has written many papers on Higgs inflation, and curiously...

I have had an idea kicking around in my head for some time now. It all started last summer when I was kayaking down a river and I had stopped in an eddy to relax for a moment. The rate of flow of the water was strong enough to make sizable vortices along the eddy fence around the boulder that...

Hi I know that gravitninos are produced in the Early Universe in reheating (after inflation), is this because the end of inflation/reheating period where the inflaton is oscillating about the minima of the potential is analogous to symmetry breaking?

Can anyone explain to me why after chaotic inflation with V=\frac{1}{2}m^2 \phi^2 that the inflaton behaves as; \phi=\frac{m_p}{m \sqrt{3\pi}t} \sin(mt). because this doesn't satify the slow roll conditions or the eqn of motion for the inflaton. I have read that it asymptotically approaches...

Hello all . I have two questions : 1 - Before inflation elementary particles such as matter and photons could not be created and destroyed or could be created and destroyed but could not be permanent ? I mean can we say matter existed before inflation but it was created and destroyed in...

Having read the 'The bigger bang' book two times over, I am struck by the fact that the author seems to ask and answer the question of quasar energy emission without stating he is doing so or explaining why it would be wrong to assume he is doing so. In the beginning of the book, Lindsey...

New to cosmology and somewhat confused. I get all the ideas indvidually, that inflation is the exponential growth in the beginning of the universe, than that gravity and matter cancel each other out to make the zero energy universe, and that a flat universe is the only one that is zero energy...

I saw this question (in a far removed forum), and I thought it was interesting. Do we have any theoretical reason (or observations) that would suggest that inflation change the fine structure constant.

I really think this paper http://arxiv.org/abs/1212.1087 which Chronos mentioned in another thread deserves its own thread. Has anyone had a chance to look at it? what do you think? This has been a lot of noise about this issue raised by people like Roger Penrose and Sean Caroll . They have...

The commonly accepted age of the universe is 13.7 billion years. I assume that assumes an inflationary epoch. Since inflation is in debate, what’s the age without it? And since expansion is accelerating, I assume expansion was slower 10 (or 20) billion years ago. Could it be infinitely old? (IE...

In brane cosmology how can there be no such thing as inflation. I was watching a lecture with Neil Turok and he said he made a bet with Hawking that says that the new Planck satellite will give us information that could prove against inflation. So, my question being, instead of inflation in the...

Does anybody know what is the status of supersymmetric inflation model after latest results of LHC concerning SUSY? Have some models been excluded? or do you know some review papers talk about that issue?

Before i begin, i will note that i truly don't have any idea of what I'm about to ask, but the questions elude me so ask i must. Firstly, Dark matter: finding it on earth. I've just finished watching a documentary on mapping our universe and within the program was shown a theory of trying to...

Hi Guys I've just made a sheet illustrating the horizon problem and how it is solved by inflation. I thought it might be handy for anyone interested in it, or having trouble with it. I'd also appreciate it if some of you could check it over and see if there's anything I have gotten wrong...

how much more power had big bang in inflation theory than in standard expansion theory? (if standard expansion big bang = 1 ) i assume it was over-c because of that power standard expansion would be 18000000 km/min and inflation... ? and after how much time did speed of light...

I understand what inflation is, but what are the reasons behind why scientists are near definitive that it indeed happened? Please go as in depth, complex, or over the top as you need/want.

How can inflation explain the particle horizon's problem?

I understand that (from what we can tell) the universe is expanding at an accelerating rate. I'm just curious if it's possible that the universe is expanding in some areas, and receding in others. despite this going against the cosmological principle, is it possible that beyond our bubble of...

This is from Krauss' A Universe from Nothing How could Guth know what density fluctuations arise after inflation? More context to better help a potential answerer:

This is from Krauss' A Universe from Nothing: It seems like he's saying that before inflation kicked in around 10^-36 or 10^-34 I forget which that the universe, I'm guessing from 10^-43 - 10^-36 was in some sort of false vacuum state, analogous to the way matter changes phase from gas to...

Why does inflation mean that the universe was much smaller at 380000 years after the big bang than we would predict from the Big Bang model alone? What would we expect the two sizes to be?

anybody knows how to calculate the period which a commodity which faces inflation takes to double it's price, without knowing anything except the rate of inflation? You must give a very shortcut method. Thanks.

"Infinite" inflation Hello all, I have a series of questions relating to the Big Bang and Inflation! First, a disclaimer: I am a science/astronomy/cosmology enthusiast, but I have no advanced education in the subjects. My knowledge is gleaned from as many books as I can read and shows I can...

Quick question from a newbie, was the inflation of the universe faster than the speed of light ? Having heard about the proposed speed of inflation (on TV) it seemed to be faster than the speed of light, surely never possible, so how fast was this inflation of the universe ? "in a...

Was cosmic inflation partly driven by the quantum degeneracy pressure of the quarks and electrons? Just after the Big Bang they would all be sitting on top of each other - just what fermions don't like to do!

What is the highest expansion rate during inflation?

I posted these on Reddit but some questions weren't answered so I was wondering if people here could help: First Part I was informed that the universe did actually exponentially gain energy during inflation and perhaps other periods of its development. So how does this affect the entropy and...

Hi, I currently have to learn about the topic of eternal inflation, at a basic level for now, I am already familiar with the topic of inflation. I don't know what are the good references to this subject. I will try to start in Weinberg's book of cosmology (the one published in 2008), but is...

does inflation affect time? my question arises from @ ~7:30min. if space itself can be used as a reference point for speed, is it an omnipresent observer? is it therefore not excepted from SR if space is moving relative to space? I have searched the forums already, I am trying not to...

Before Higgs symmetry breaking of SU(2)xU(1) electroweak unified force or even before that, when strong and electroweak were unified as GUT theories propose, the vacuum was different from today's universe. What effects had these different vacua on the evolution of the universe? thanks

In GR gravity is seen as a property of space-time , curvature. Now we know that sometime after the plank's time we had the universe dominated by radiation ( recombination) as such the rate of inflation was in the range of ~ 10^30 m/s , which as you can see is considerably larger than the VOL (...

Cai Easson avoid "eternal inflation", use Higgs to seed structure Cai and Easson's paper takes off from the seminal paper of Shaposhnikov and Wetterich that is discussed here at BTSM https://www.physicsforums.com/showthread.php?t=560031 Shapo-Wetter predicted 126 GeV Higgs in 2009 on the...

I can understand how can inflation give rise to the isotropy of the CMB, but that it can give rise also to the irregularities in the CMB...!? Please, can anyone explain me this? thanks.