Inflation Definition and 399 Threads

I just read the thread on inflation is very unlikely. Then I read the paper by Abhay Ashtekar, David Sloan Loop quantum cosmology and slow roll inflation Although, I did not comprehend all of the implications what seemed to be implied was Given enough mass at some critical density...

How is it possible that the universe expanded faster than the speed of light during inflation when this is the "cosmic speed limit"?

Do you agree with physicist Sean Carroll that inflation is very unlikely? http://blogs.discovermagazine.com/cosmicvariance/2010/07/08/how-finely-tuned-is-the-universe/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+CosmicVarianceBlog+%28Cosmic+Variance%29

Was reading that shortly after the BB, the universe blow up by a factor of 10 to the 50 in 10-33 seconds. What does 10 to the 50 mean in terms of distance & size? All i know is its a large number.

Do the current models of inflation contain an implicit understanding that gravity is some how turned off during the inflationary expansion? Does the scientific community believe that gravity is a temperature dependent phenomina?

Can't we simply assume that the initial condition for the universe is perfectly spherically symmetric, and the problem is solved? In other words, can't we make the CMB homogeneous just by imposing homogeneous initial conditions? The fluctuations can be explained by quantum effects. Of course...

Please forgive my ignorance but: I am trying very hard to understand how expanding space works. The problems I have are: 1. If expanding space has enough "connection" (friction?) to pull galaxies apart then it should also have a resistance to planets in orbit, rockets continuing on their...

It seems many forms of inflation, such as eternal inflation and chaotic inflation imply a multiverse, but do they all?

Noob alert. Totally naive question. Reading V.J. Stenger's "God: The Failed Hypothesis". He says that the observable size of the universe, 10^26 meters, is only 10^61 times bigger than the Planck distance, and he says inflation caused the universe to expand by a factor of 10(10^100) from...

According to SR theory, relative motion leads to -length contraction -mass inflation -time dilation. In GR theory, gravity leads to time dilation. Does it also lead to -length contraction? -mass inflation?

cosmology strings vs loops How well does string cosmology account for inflation, CMB, gravitational waves, evolution classically using FRW metric? does string cosmology offer either qualitative or quantitative predictions? This paper addresses these in the loop framework...

In essence, is it the case that there is no advancement in understanding that we still must assume that like in the classical big bang theory that conditions were 'just so' at the 'start'? I don't have a problem with inflation but essentially the same problem remains. Conditions are assumed...

I have a question that bothers me. well, i have a lot of question that bother me. But for now, i will share only one. When inflation began after the big bang, the amount of space that was created exceeded the speed of light. How was that possible?

I was wondering, if inflation caused space to expand so rapidly, what happened to slow it down to the current rate?

What is the "real" rate of inflation? What is the "real" rate of inflation? The U.S. Federal Government used one formula to calculate before the Clinton administration and now uses a different formula. The two give answers that often differ by a factor of two. Which, if either, is the right...

hi everyone, i am not a physicist, so please forgive me and help me to clarify some basic concepts. in the context of the inflation of the universe, as i understand it, it was the energy density of the void that expanded space-time, so that the energy density remaining (almost) constant coupled...

does the inflation theory say that there could be infanet other bubble iniverses or that our bubble universe is expanding as the galexys move outwards?

The Big Bang model describes a smoothly expanding universe from a point where the current laws of physics break down. However if the universe is infinite, it would be infinite down to this point and presumably before it. This would imply instantaneous inflation from 0 to infinity. The universe...

What is inflation (in big bang theory not economics)?

Why do we need an inflation to solve the horizon problem? http://en.wikipedia.org/wiki/Horizon_problem If O(t) is omnuim ((c) Frederik) - wavefunction of the whole Universe then initial conditions like O(t=0) = const solve the problem?

Is it possible to find out how much the universe grew by during the period of inflation after the big bang?

Mtd2 spotted this paper by Steven Weinberg that just went on arxiv. http://arxiv.org/abs/0911.3165 Asymptotically Safe Inflation Steven Weinberg 13 pages (Submitted on 16 Nov 2009) "Inflation is studied in the context of asymptotically safe theories of gravitation. It is found to be possible...

Not so long ago, any article, book or treatise regarding the history of the universe seemed to take the "inflation" theory as more or less established fact, whilst also admitting that the finer details were not quite figured out. Is this spectacular theory still regarded as being part of our...

Could someone recommend some papers or books on Inflation? I know nothing about it, so I need some accessible ones. Thx.

Hi all, I know that inflation solves shortcomings of Standard big bang cosmology, but doesn't intoducing inflation puts us in another puzzle , what is the mechanism which is responsible for inflation? I mean what is the more puzzling our universe with inflation or without it?

My question goes like this: Did the inflation following the Bing Bang caused matter to emerge as it is in our universe? In other words, was it the inflation itself that gave matter - electrons, neutrons and protons - its properties (physical size, quantums, velocity, mass), or perhaps the two...

You can get a calculator and start counting the errors and false assumptions contained below if you want.. but I got to ask.. If the furthest we can see is 14 billion light-years away (because it's been 14 billion years since the big bang and that's all the time light has had to travel such a...

I hope someone can help me understand some inflation principles. In Alan Guth's popular book: The Inflationary Universe, he presents a schematic of a false vacuum universe decaying into pocket universes. The false vacuum expands exponentially as the pocket universes are continuously...

Homework Statement During 1988 Nicaragua's inflation rate averaged 1.3% perd day. This means that on average, prices went up by 1.3 percent from one day to the next. By what percentage did Nicaraguan prices increase in June of 1988? What was Nicaragua's annual inflation rate during 1988...

Can someone please clarify if the energy scales of Inflation & GUTs are identical, or model-dependent ? One typically sees ~10^15 Gev to 2x10^16 Gev in the literature, which is a small variance, but its not clear if there are `standard values'. I am also curious if one can have inflation...

What exactly is cosmological inflation? Just a hypothesis that the rate of expansion is increasing? What is negative-pressure vacuum energy density? If the universe is expanding faster than the speed of light, how do any photons reach us from anywhere other than our sun? Thanks in advance!

When using the Friedmann equation (flat space, no cosmological constant): H = sqrt (8 pi G / 3 ) * rho, if we use rho in mass/volume, H is in (time)^-1 like it should. Now for some inflation models, we use: H = sqrt (8 pi G / 3 ) * V(Phi). It seems that V(Phi) should also be able to be...

Hypothetically, was there ever a time during inflation of the universe when the density of the universe would have been equal to that of water, and we could have swam through it? If so, how big would the universe have been at that moment?

I was reading about inflation on Wikipedia (warning: I don't really understand physics and cosmology) and I noticed that it said that inflation and dark energy were kind of broadly similar but that their energy scales were off by a factor of about 10^27. This weirded me out a little because I...

I keep reading that the energy scale of inflation is possibly 1024eV, while the energy scale of dark energy is around 10-3eV. What exactly are these scales referring to? Is it the energy required to accelerate the universe at the corresponding rates of acceleration? What...

Hi, I haven't found special topic about cosmology on this site so I hope this cathegory fits the best. The questions are: 1) Is cosmos(universe) finite or infinite? According to some articles I have read about inflation it seems that inflation theory works only with finite number of particles...

Hi, I'm totally lost on how inflation solves the horizon and flatness problem. Flatness Problem Explanation I have d/dt(1/Ha)<0 and therefore |\Omega-1| is driven towards zero rather than away from it. My Confusion Doesn't inflation increase the volume of the universe...

Is it true that we should borrow money during high inflation periods and lend during deflation periods?

Is chaotic inflation eternal into the past forever, as well as into the future forever. In the theory was there a beginning to it, or has it always been?

In ordinary GR geometry, the Higgs field cannot play the rôle of the inflaton, so to imagine inflation one has to introduce some exotic field that is not part of the Standard Model. Something completely made up must be introduced to make it work. Not so in the context of non-commutative...

I am designing an exhaust powered vehicle car jack air bag. I have calculated the mass flow rate and velocity of the exhaust gases leaving the vehicles exhaust pipe. I need to calculate the amount of time it will take to inflate an air bag of a particular size. What equations do I need to be...

I am designing an exhaust powered vehicle car jack air bag. I have calculated the mass flow rate and velocity of the exhaust gases leaving the vehicles exhaust pipe. I need to calculate the amount of time it will take to inflate an air bag of a particular size. What equations do I need to be...

The FTL expansion of the early universe is explained by the "stretching" of spacetime itself so that a meter stick would be uniformly "stretched". Two questions: 1. Is the stretching of the meter stick only in the direction of the expansion? Is it sensible to talk about the direction of...

I wonder if quantum gravity effects can explain Inflation after the Big Bang? For example, in Loop Quantum Gravity, there are area and volume operators and eigenvalues, etc. Would there be jumps from one volume state to another with time? Thanks.

Homework Statement If nominal GDP grows with 7 % and the inflation is 2% What is the growth in real GDP The Attempt at a Solution is it 1.07/1.02 or ln(1.07) - ln(1.02) ?

Homework Statement A balloon is being inflated to its full extent by heating the air inside it. In the final stages of this process, the volume of the balloon changes from 4.00 x 106 L to 4.50 x 106 L by the addition of 1.3 x 108 J of energy as heat. Assuming that the balloon expands...

arXiv:0810.3022 [pdf, other] Title: Cosmological Inflation: Theory and Observations Authors: Daniel Baumann (Harvard), Hiranya V. Peiris (Cambridge) Comments: 18 pages, 12 figures. Invited review to appear in Advanced Science Letters Special Issue on Quantum Gravity, Cosmology and Black...

Hello all, I'm new and this is my first Science forum I've ever joined. I got interested in Physics about 3 years ago after reading a book called What Remains to be Discovered. It opened my eyes to a lot of things, especially Quantum Physics. But, the most difficult thing to wrap my head...

I know very little about the economics of countries, so i came here to ask, how is Zimbabwe surviving with its massive inflation and falling exports, i have seen reports of factories closing for lack of electricity and the lack of essential imported parts, also reports that the inflation rate...

I am presently reading a paper on Inflation. It uses the term Hubble length. Can someone provide the Hubble length in cm.