Questions tagged [big-bang-theory]

Questions regarding the currently prevalent cosmological model for the origin of the universe.

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12
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2answers
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 ...
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0answers
57 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 ...
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1answer
56 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
73 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 ...
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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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0answers
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
111 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 is just a ...
2
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1answer
107 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
198 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
42 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
213 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 ...
7
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1answer
88 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
159 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
290 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
177 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
61 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
66 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
139 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
42 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
115 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
141 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?
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0answers
77 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 ...
2
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2answers
305 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
145 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
156 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
107 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
592 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
1k 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
92 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
113 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!
3
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1answer
70 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
61 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
94 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 ...
3
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2answers
191 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
811 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]. ...
9
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1answer
753 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?
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1answer
127 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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1answer
509 views

What is beyond the observable universe? [closed]

What is beyond the edge of the observable universe? Scientists say that the Big Bang is the cause of all creation in the known universe, but it would seem the bang must have happened in the center of ...
3
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3answers
693 views

How can the universe be expanding faster than speed of light? [duplicate]

So the story goes like this: A long time ago, 13.799±0.021 billion years to be exact, something happened. It was a big bang, loud explosion and universe came to existence. It grew and grew, and now ...
0
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1answer
275 views

Why do we we even exist? [closed]

It came to my mind one day that why does this universe even exist and why do we even exist and like we are enclosed in the so called atmosphere and a floating rock in space called the Earth, so is ...
3
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2answers
186 views

Is there a way to know how the magnetic field was at the very beginning of our universe?

I recently read that Gamma-ray bursts are catastrophic events, related to the explosion of massive stars 50 times the size of our sun. If you ranked all the explosions in the universe based on ...
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1answer
170 views

Was Milky Way formed after Sagittarius A Explosion?

Is it possible that most galaxies (and our galaxy) were formed from leftovers of supernova explosions? In order to have a black hole 4,000,000 x solar mass the initial mass of the star should have ...