Questions tagged [cosmological-inflation]

Questions regarding the phenomenon in the early universe characterized by an extreme expansion of space.

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5
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4answers
513 views

Distinction between metric expansion and objects just moving apart from each other?

I see explanations likes this: Galaxies and other sources, then, are not strictly expanding away from each other but rather are attached to the fixed grid on the expanding fabric of spacetime. Thus, ...
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1answer
105 views

How distant were the furthest currently-observable cosmic events when their currently-observed radiation was emitted?

(Edited for clarity. Thanks to James K and Connor Garcia.) This question about the most distant, observable cosmic objects made me wonder if we know the distance that was between us and them at the ...
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41 views

How much does the Higgs field contribute to the energy of empty space?

The Higgs field was not spontaneously broken when the universe was young and hot (like I am not...:)). At the very high temperature that existed back then, the Higgs' energy of the Higgs field was non-...
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4answers
764 views

Is the Universe really expanding at an increasing rate?

Here's what I just read from Wikipedia's page on the Hubble Space Telescope: While Hubble helped to refine estimates of the age of the universe, it also cast doubt on theories about its future. ...
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1answer
171 views

Can eternal inflation and gravity explain dark energy?

First of all, I have absolutely no background in astronomy and physics. I just watch a lot of "i-hope-scientific" youtube channels talking about physics and astrophysics and I can kind of follow the ...
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2answers
933 views

What explains the existence of energy/matter if it cannot be created or destroyed?

If the energy/matter that was contained in the singularity before the Big Bang had always existed, and if it’s true that energy/matter cannot be created or destroyed, then what explains its existence?
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1answer
114 views

Understanding better the factors on $C_l$ in Angular power spectrum and Relation with Matter power spectrum

I am looking for an explanation on the angular power spectrum. I found this extract that is interesting but not fully understood for me (I will cite the step that I didn't understand) "what is ...
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0answers
50 views

How do we know or predict which particles were present before Big Bang Nucleosynthesis occurred?

I'm reading Carroll and Ostlie's "An Introduction to Modern Astrophysics". In the BBN section, they describe that the universe contains a mixture of photons, electron-positron pairs, and ...
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2answers
146 views

What powered the Big Bang?

According to the first law of thermodynamics, law of conservation of energy states, The total energy of an isolated system is constant; energy can be transformed from one form to another, but can be ...
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1answer
293 views

Does the holographic principle contradict eternal inflation?

As it is for example explained here, Andrei Linde's chaotic inflation is among the potential winners or survivors of the spring cleaning induced by the potential detection of primoridal gravitational ...
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0answers
76 views

Accuracy of the Inflation theory

In the Inflation theory, it said that the Inflationary epoch has happened $10^{-32} \,\mathrm{s}$ after the Big Bang, and I cannot find anything related to how this number was calculated and how ...
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1answer
99 views

What's the furthest distance that something could travel and eventually come back to Earth?

Imagine u shoot a photon into the sky at a mirror far away in space, and you want the photon to bounce off the mirror and eventually come back to you. Considering the cosmological constant, what's the ...
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2answers
146 views

Why can't we point the centre of the universe from inflation graph we see?

This question is not about whether it makes sense to have a centre of the universe or not instead, it's about the inflation graph we used to see while describing the Big Bang. From the inflation graph ...
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1answer
270 views

What happened before, Big Bang or inflation?

I always thought that the cosmic inflation happened after the big bang (10-36 sec) and lasted for a very tiny fraction of time). Now, I recently came across a couple of articles (links below) claiming ...
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1answer
81 views

Was Guth inflation propelled by what we now call "Dark Energy"?

The more powerful our telescopes become, the more we are able to see earlier and earlier remnants of Guth Inflation. Assuming that it makes sense to associate a location, BB, in space-time where the ...
3
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1answer
1k views

What will the universe be like in a googolplex years time?

It will be cold and dark in 10^(10^100) years. What else can be said of the state of things in the far distant future? Will everything have fallen into supermassive black holes and then radiated ...
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3answers
7k views

Does time slow down because the universe is expanding at an accelerating rate?

If the universe is expanding at an accelerating rate, such that the galaxies' moving away from each other is accelerated, then time should also slow down. And when universe will accelerate to the ...
3
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1answer
234 views

Time dilation due to the expansion of the universe

This is not a homework question. I want some help in being able to clearly perceive the expansion of the universe and the consequences thereof. We know that the universe is expanding in an ...
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0answers
46 views

Probability of collision of another bubble universe with our universe

This is rephrased from a previous question and expanding on it. Considering the model of an "inflating" universe which extends infinitely in past (and possibly future) time, constantly creating new ...
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1answer
60 views

Problem with denoising the BICEP2 data?

This question pertains to this article which talks about why the BICEP2 measurements of B-mode polarization in Cosmic microwave background radiation turned out to be noise from galactic stardust. They ...
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1answer
123 views

What do cosmologists mean when they talk about "the running of the spectral index"?

All I know is that the spectral index is related to the CMB, and that it has to be slightly less than 1 to favor inflation.
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2answers
787 views

Are there ways to estimate size of the "whole universe"?

Words escape me, but by "whole universe" (I think) I mean everything that's spatially connected to the observable universe in a conventional sense. If there is a better term for it, please let me know!...
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0answers
93 views

The nature of cosmological inflation — unfolding dimensions?

While the paradigm of cosmological inflation is well established, the nature of the inflation is not known and is tackled by introduction of a hypothetical "inflaton" field. I was wondering if there ...
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2answers
120 views

What is the difference between the way light travels in a gravitational field and the way it travels through an expanding universe?

A photon is travelling through space. As it travels, the space through which it travels is expanding Does this describe A - a photon travelling from a distant galaxy to earth B - a photon travelling ...
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1answer
183 views

Time-frame regarding cosmic expansion and the bound state of the Virgo Cluster

Due to accelerating cosmic inflation, other galaxies and galaxy clusters will eventually race toward the Hubble horizon apparently away from us, placing them effectively out of our sphere of influence....
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4answers
312 views

What is our universe expanding into?

From inflation theory and other theories explaining the birth of the universe, the universe is expanding and recently it's been discovered that the expansion has been accelerating. My question is ...
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1answer
106 views

Fundamental axioms in LCDM

What are the axioms (if any) behind the LCDM model of cosmology? NB: axioms, not postulates (e.g., inflation)
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1answer
59 views

Where can I find source data for the graph of metric expansion over time, as shown in this ESA web page?

This web page from ESA/Hubble, shows the size of the universe over time. (I know that "size of the universe" is a gross simplification and open to multiple definitions and ambiguity, but this kind of ...
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2answers
208 views

BIg Bang Happened everywhere

According to the Friedmann equations big bang happened everywhere, but if we account for inflation theory, big bang did not happened everywhere. How ? Anyone please explain. Please see the video for ...
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1answer
170 views

How does inflation justify the nonexistence of magnetic monopoles?

It is said that inflation justifies that magnetic monopoles don't exist. Can anyone explain how inflation theory explains the non existence of magnetic monopoles?
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2answers
125 views

Does Flat Universe mean even distribution?

I've read through all the other related answers to "flatness" questions but I need a bit more clarification. I understand that a triangle in a 2D universe would not equal 180 degrees in both a closed ...
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4answers
381 views

What is the acceleration for the expansion of the Universe?

I've found that the speed of expansion is about $70\frac{km}{s\cdot 10^{6}pc}$. But what is the acceleration of expansion in terms of $\frac{km}{s^{2}\cdot 10^{6}pc}$ ? I want to know how fast this ...
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1answer
152 views

Could the expansion of universe be a side effect of gravity?

Could the expansion of universe be a side effect of gravity? I mean maybe gravity "attracts things" at a "small" distances and repells them at "larger" distances? Do we have any theory/hypothesis/...
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1answer
81 views

Does wavelength affect redshift caused by the metric expansion of space?

Does wavelength play a role in cosmological redshift? Do we see certain wavelengths affected less by expansion or notice any delay in arrival of certain wavelengths? How accurate are any observations?...
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106 views

What is the difference between Steinhardt's and Neil Turok's cyclic cosmology and Guth's inflationary model and Hartle, Hawking no boundry cosmology?

I have been reading some cosmology and need to ask the experts at this point some specific points. I must admit I am a little confused. There are a few models of the universe and may be necessary at ...
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1answer
4k views

What are the significant assumption of the Inflation Theory? [closed]

Can it still be considered theory ?, because I can't find it's major or significant assumptions.
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2answers
374 views

Expansion again: where does the energy come from?

Is it sensible to ask for the overall increase in potential energy when looking at the baryonic mass in the universe moving away from each other, that is, moving against the direction of the force ...
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0answers
205 views

Is cosmic inflation still a hypothesis?

Is Cosmological inflation still considered as hypothesis? Is CMBR evidence not enough?
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2answers
230 views

A black "superhole" possibility?

When matter crosses the event horizon, it is easy to imagine that matter is torn apart into their individual components by tidal wave effects. Atoms would be ripped apart eventually. At one time, the ...
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2answers
184 views

Could Dark Energy be a "Cosmic Gravity Background"

Could dark energy (the accelerating expansion of the universe) be the result of gravity from the dense past universe "pulling" outward from all directions? The universe theoretically started out ...
3
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1answer
159 views

Are there expanding-universe cosmological models that do not include inflation?

I'm happy that the universe is expanding, because we have good scientific evidence in the form of galactic redshift. The Wikipedia Hubble's law article gives what I think is a fair explanation of that....
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1answer
101 views

Could the accelerating expansion of universe inidicate we are surrounded by "denser" space? [closed]

I'm quite novice about all this, only have read some vulgarization books and sites, but I wonder: could all the observable universe be falling outwards on some non-observable, more compact kind of ...
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2answers
360 views

Is the Big Bang inflation caused by Dark Energy

The rate of expansion of the universe after the Big Bang is described as Inflation. It is stated as being initially very fast then slowed. But the expansion is still continuing. Some say expansion is ...
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1answer
348 views

Is the M81 group bound to the Local group?

Andromeda and the Milky Way are set to collide in 4bn years. Will the Local Group collide with M81, and what about further away groups? if so, when?
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1answer
130 views

What are the concrete technical arguments supporting the idea that the wave function of the universe can be written as partition function?

In this talk, the not yet settled down idea that the wave function of the universe could potentially be written as the partition function of a scale invariant statistical field theory is mentioned: $...
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2answers
417 views

How could universe inflate itself out of the very dense and curved early spacetime? Could it happen in a black hole too?

Wasn't spacetime as much curved as a black hole directly after Big Bang, because mass was so densly packed? Wasn't everything like an event horizon and how could things expand across it? Could ...
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1answer
2k views

Does the universe expand at the same rate everywhere in the universe?

Specifically, I am wondering if some areas of the universe expand faster than other areas and whether the faster expanding areas diffuse the expansion through the slower expanding areas or does the ...
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1answer
144 views

Standard Big Bang model and space curvature

Why it is said that in standard Big Bang model space curvature grows with time when the Universe expands? My intuition is that it should be the opposite. I saw this in a book talking about the ...
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1answer
192 views

Why is the CMB not simply travelling parallel to us? [closed]

When we look to the distant farthest reaches of the universe we see light that was emitted at the big bang 14 billion years ago. But the universe was tiny back then so that light, which is only ...
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2answers
136 views

Was time different before the great inflation?

In time different during the first second after Big Bang than it is now? Inflation had a dramatic effect on space, and spacetime is one thing. Was the properties of time affected too? Curved spacetime ...