Questions tagged [big-bang-theory]
Questions regarding the currently prevalent cosmological model for the origin of the universe.
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Was universe spawn from nothing? [duplicate]
Was universe spawn from nothing?
Until now, scientists figured out that the Big Bang happened from a tiny particle which was infinitely energy densed and having infinite mass. If that is the case ...
3
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1answer
120 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
88 views
Why is the Cosmic Microwave Background at the same distance no matter the direction we look?
I've read from different sources that:
The CMB is visible at a distance of 13.8 billion light years in all
directions from Earth, leading scientists to determine that this is
the true age of the ...
4
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2answers
541 views
What is meant by “vastness of space, which now filled a volume of a hundred million light years”?
I am reading the book Cosmic biology: How life could evolve on other worlds (citation below) and do not understand the meaning of the following paragraph from page 4 (emphasis mine):
It took 200,000 ...
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1answer
82 views
How can something infinitely big have expanded from an infinitely small?
Please help me reconcile what I see as contradicting theories:
The universe began with the Big Bang and expanded from an infinitesimally small point.
The universe is infinite.
How can something ...
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1answer
138 views
How did matter first come into existence? [closed]
How did matter come to be?
Why is there matter if matter and antimatter cancel each other?
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1answer
4k views
At the Big Bang, when everything was close together, why did it not “collide”, violating Planck length or Pauli Exclusion Principle?
How could so much matter, or "all" in fact, have been concentrated in a smaller universe without being in the actual same place? Why did this not result in undercutting the Planck Length or ...
4
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0answers
81 views
Does the cosmological principle apply to the entire universe?
Some cosmological models assume that the universe is isotropic and homogeneous and that is also flat and infinite. If the universe is infinite now it was infinite immediately after the big bang. If ...
2
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1answer
63 views
Types of Multiverses [closed]
Can anyone recommend me books or other online resources on the concept of the Multiverse, it types, and about higher mathematical dimensions of space-time. I have been interested in such topics for a ...
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1answer
81 views
Is our universe a singularity?
According to the Big Bang theory our universe used to be a lot smaller in size.
It actually used to be so small that in the beginning it used to be a singularity.
And the universe started to expand ...
2
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0answers
46 views
How is the big bang a plausible theory? [duplicate]
In the Big Bang Theory, it is said that it started with a small speck of matter, yet we have an unimaginable mass of expanding universe which is assumed as immeasurable. If the theory of "Matter ...
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23 views
When did relatvistic effects take hold after the big bang? [duplicate]
As far as I understand it the universe did not become a black-hole at the big bang.
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26 views
Is there a place where one can see the beginning of the universe? [duplicate]
If the night sky Is dark because we’re seeing the world as it was a long time ago, when there wasn’t much to see, is there a place on the universe where we can see the universe at the beginning of ...
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1answer
142 views
Why is CMB an evidence of hotter and denser early Universe?
In his book Gravitation and cosmology, Steven Weinberg says that CMB makes it "difficult to doubt that the universe has evolved from a hotter denser early stage".
In my understanding, CMB ...
2
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1answer
109 views
Did Einstein supported Big Bang Theory cosmological model?
Einstein made many predictions, including gravitational waves and the possibility of black holes.
Relativity is taken into consideration for the Big Bang model, so did Einstein agree with it or did ...
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2answers
205 views
Is Olbers' Paradox Nonsense? [closed]
Ok, this is a bold question, I know. But, let me explain: After first hearing about Olbers' paradox, I found that something seemed 'off' about it, so I looked into the subject as much as my skills (...
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0answers
32 views
Must all galaxies in a galaxy cluster have the same expansion rate?
If we observe a distant galaxies cluster where all galaxies travel with the same speed away from us, except for one galaxy whose speed is significantly lower than of the neighboring galaxies. Does ...
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1answer
48 views
What reference frame do age-of-the-universe calculations assume?
I'm thinking, in particular, about general relativity. When we speak, for example, of neutrino decoupling, what do we mean when we say this happened in the first second after the Big Bang? Do we mean ...
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2answers
217 views
Are there only a set number of atoms in the whole universe?
As per the title, are there only a set number of atoms in the universe? Or does the universe make more atoms, and if so, how does it work?
I'm a high school student that just had a question during ...
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1answer
93 views
Understanding The Fluctuations In The CMB Maps
If I'm understanding this correctly the fluctuations in CMB are a result of the "last scatter" of photons when electrons joined together with nuclei that before this formed plasma. CMB is among other ...
8
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1answer
162 views
How do we know so many details about Big Bang, but we do not know if Universe is finite/infinite?
I understand that this question may be too vague, but I am confused about the following:
On one hand we know a lot of "details" about Big Bang, like really precise details, evolution of universe, age ...
0
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2answers
337 views
If space is negative energy and matter is positive energy then does that mean the universe is finite?
I was reading a book by Stephen Hawking, it was written that universe is made up of 2 ingredients,i.e., space and energy and space was the negative energy, so they add up to 0. But since space is ...
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1answer
185 views
What does it mean for space to expand?
In this YT video Michelle Thaller says The Big Bang wasn’t an explosion but an expansion and as such there's no empty center where the explosion would've been.
To explain expansion she uses the ...
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6answers
7k views
Why do galaxies collide?
If the universe is expanding outward, what is the processes for one galaxy to get off track enough to collide with another?
Say, the Andromeda Galaxy and the Milky Way.
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1answer
66 views
Have we measured or found evidence of a detectable origin point of the big bang? [duplicate]
Based on reading the wiki page of the big bang, a simple question with a probably not a simple answer came to mind.
The statement on the wikipedia page was.
Since Georges Lemaître first noted in ...
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0answers
66 views
Is it possible for 'pre-big bang' empty space to have the property of being able to spawn matter and/or energy into existence? [closed]
.. and if so, wouldn't this also mean that during this event, time would be created as a collateral, as a canvas for this property to manifest?
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0answers
69 views
Expansion of space - how do we end up with an unobservable region?
I've just been answering a question on this issue,in physics SE,and realised that my answer conceals a point I don't myself understand.
I understand that
The expansion of metric isn't affected by ...
4
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1answer
140 views
How much helium has been created since the Big Bang?
When I try to find figures for the amount of helium today and just after the Big Bang, I get similar figures. I was expecting that all of the stars since then would have created more helium. Is the ...
3
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0answers
43 views
How did the Big Bang occured if before that there was no time? [duplicate]
I am thinking, that if the Big Bang created time, it implies that before the Big Bang there was no time (correct me if I am wrong).
My question is that, if there was no time before the Big Bang, how ...
4
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1answer
117 views
How can you verify the theories presented on TV shows like “How the Universe Works” is current and/or valid? [closed]
There are many TV shows such as "How the Universe Works" that explain theories about the origin of the universe such as the Big-Bang Theory.
What resources can I access to verify the scientific ...
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2answers
163 views
How does science knows what is the early universe?
I've read about Hubble seeing the brightest quasar in the early universe. Question is, how does science knows what is early and what is late?
Please correct me if I'm wondering, but after the big ...
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1answer
147 views
Why more matter still left after collision with anti-matter?
Question implies all, why is that? Why we exist even after equally creation of matter and anti-matter, any possible exception?
2
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0answers
79 views
Is there a theory about a collision between a shrinking universe and a new expanding universe?
I recently read a post on a discussion board about the creation of our current universe that stated, and I quote:
[T]he shrinkage activity of the old universe and the new Big Bang expansion ...
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2answers
312 views
How could time only have started with the Big Bang?
I understand that before the Big Bang time (as well as dimensions) didn't exist. But how could this be? If there was no time then nothing could change, and so time itself couldn't come into existence.
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1answer
147 views
Is it possible that the Universe is expanding due to additional Big Bang events?
Is it theoretically possible that the Universe is expanding due to additional Big Bang events that have occurred at the same location that the original Big Bang occurred at?
Perhaps there has been an ...
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1answer
160 views
How thick is the cosmic microwave background, including the part we cannot see within the observable universe?
What I want to know is how thick the observable universe is from the point of the cosmic microwave background and beyond.
It appears the thickness of the cosmic microwave background itself (the part ...
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3answers
113 views
If the Higgs field only formed after the Big Bang, how was hydrogen formed?
These two statements seem to conflict, but since we're here they can't:
Electrically charged particles cannot be massless.
Hydrogen was created at the moment of the Big Bang.
However, the Higgs ...
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3answers
661 views
How did space start?
How did this 'black fabric' that we call space start? How was it made? How was the initial singularity formed? How did the first atom come into existence?
If it all started from a tiny particle that ...
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1answer
2k views
What created the big bang's singularity?
I have heard theories for the big bang like: of another universe existing before the Big Bang, or an unstable white hole that blew up, or our universe detaching from our mother universe, or our ...
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1answer
96 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
114 views
Just after the Big Bang, was the space, in its entirety, filled with Hot gas?
After the Big bang occurred, was the space filled with hot gas totally?
If there's any problem in my question please inform me. Thanks!
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1answer
75 views
calculation of characteristic expansion time of the universe
Hubble's constant is estimated at 15km/s at a distance of million light years, without considering effects of mutual gravity, relativity, etc.
I am trying to calculate the characteristic expansion ...
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1answer
62 views
Location of Big Bang [duplicate]
Can I point to somewhere in the sky where the Big Bang happened? A pathway so to speak on where we (and our progenitor elements) came from?
0
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1answer
97 views
Singularity at the time of origins
According to the big Bang Theory, the universe have started from a point and it describes how the universe expanded from a very high-density and high-temperature state.The initial singularity was a ...
5
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1answer
136 views
Why Helium could be produced in first minutes of big bang but not heavier elements
At what extent could be sure that no heavier elements than helium could be produced, if we know that matter in universe today is about 25% composed on helium, why could be so sure that the kind of ...
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2answers
194 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 ...
2
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1answer
112 views
Is it fruitful to search for a correlation between rates of in-falling matter in black holes and the expansion rate of our universe? [duplicate]
To my understanding, white holes are hypothetical objects that are time-reversed black holes; black holes gravitationally "suck in" matter whereas white holes "spit" matter back out. As such, I think ...
2
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1answer
892 views
How could the universe be a few light years across just 1 second after the big bang?
I was skimming through Neil deGrasse Tyson's book Astrophysics for People in a Hurry when I noticed he says something curious on page 26:
"By now, one second of time has passed [since the big bang]. ...
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1answer
774 views
Was the whole Universe close to Big Bang very small, or just very dense?
I am sorry this question is probably silly for professional astronomers, of which I am not one.
I often hear at lectures that immediately after the Big Bang, the universe was small, say, the size of ...
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0answers
50 views
How the observed deuterium abundance constrains big bang nucleosynthesis?
I know deuterium can be used as a good tracer to constrain the big bang nucleosynthesis. But can anyone tell me the in details how this is actually done?
