Questions tagged [cosmological-inflation]
Questions regarding the phenomenon in the early universe characterized by an extreme expansion of space.
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If the energy density during inflation were lower, how would the CMB look in comparison to the observed CMB today?
I am assuming that a big bang followed by inflation is still theoretically possible with a different starting density. Would the CMB look the same but just colder?
user50918
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Are vacuum fluctuations that produce dark matter correlated to fluctuations that produce baryonic matter?
When cosmic inflation began vacuum energy fluctuations created matter . But were the fluctuations that created dark matter dependent on the fluctuations that created matter ? Is the ratio of dark ...
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Why is it assumed that the universe started out with a size equal to the Planck length?
What if the Planck length is the distance between particles when the universe was very small .
For a spherical ball of 10^ 78 protons that would give the universe a radius of 10^26 X 10^-35 = 10^-9 ...
user50623
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Why do cosmologists assume that inflation began shortly after the Big Bang, rather than at the exact start?
Somehow, I have never come across an explanation of why cosmologists claim that the alleged inflation of the very early universe occurred not at the Big Bang, but very shortly afterwards (~10^-36 to ...
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Why is the latest Webb discovery of early-age universe considered so important?
The past week, news were flooding of an unexpected discovery of James Webb Space Telescope. In many articles it is mentioned that cosmologists cannot explain the formation of galaxies of this ...
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Have astronomers taken into account the fact that red-shifted light from far-away stars is also very old when studying the expansion of the universe?
I am aware that Hubble discovered that the further away a galaxy is the greater its redshift. What I don't understand is how astronomers can be sure that distant objects are still moving at greater ...
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Does cosmic inflation spawn from empty space, or vice versa?
In the eternal inflation model supported by Sean Carroll and others, the basic premise is that inflation is continuous in places across an infinite cosmos, and that bubble universes (like our own) are ...
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How can the universe be flat?
In each video I see on Alan Guth or anyone explaining cosmic inflation and how it solved the flatness problem, it is said that "the repulsive effect of gravity thus change how omega evolves and ...
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How did cosmic inflation even occur?
I wanted to ask this question that which inflation model shall i believe?
Following below will be MY UNDERSTANDING (MAY NOT BE CORRECT) OF IT:
I read "A Brief History of Time" and in chapter ...
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Why is cosmological redshift treated as a different phenomenon to doppler redshift? [duplicate]
I understand that the expansion of the universe causes unbound structures to move apart from each other. This means that unbound structures have negative relative momentum due to universal expansion.
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Cosmic inflation was faster than light. Why would a false vacuum decay bubble only expand at the speed of light?
I have been reading about cosmic inflation: the initial step in the formation of our universe when space/time inflated to fill whatever preceded it. I understand that this inflation happened faster ...
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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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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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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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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 ...
user16492
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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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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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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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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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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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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 ...
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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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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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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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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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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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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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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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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?
user23327
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Fundamental axioms in LCDM
What are the axioms (if any) behind the LCDM model of cosmology?
NB: axioms, not postulates (e.g., inflation)
user19333
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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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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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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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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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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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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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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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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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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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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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Is cosmic inflation still a hypothesis?
Is Cosmological inflation still considered as hypothesis?
Is CMBR evidence not enough?
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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 ...
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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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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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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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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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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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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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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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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 ...
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