According to the current cosmological theories, it's the model that explains the early life of the universe, starting from a rapid expansion of hot and dense matter.

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Will the background radiation get “dimmer”? If so when will it be “turned off” [duplicate]

This video http://youtu.be/_mZQ-5-KYHw talks about the background radiation which we can observe today. It's from the beginning of the universe and has traveled so long that the expansion of the ...
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132 views

Why did the big bang need to produce equal amounts of matter and antimatter? [duplicate]

I've tried to find an answer for this but couldn't find one. Whats the problem with matter being created with little or no antimatter
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55 views

TEO: raise of a System [closed]

I think this question is settled somewhere betweeen physics and philosophy and we surely can not find a answer that fits 100%, but lets talk about it. While thinking about how the universe and its ...
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163 views

How can the Big Bang singularity exist in spacetime if it has zero volume? [closed]

How can the Big Bang singularity exist if it has zero volume? I tried googling to find the answer - no help. Can someone give a general idea how can the big bang singularity exist even if it has zero ...
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Why is the graph of CMB/black-body radiation asymptotic?

Speaking of this graph of blackbody radiation, I see that the graph goes to 0 asymptotically: As we go to higher and higher frequencies, the energy of a single photon becomes increasingly high. ...
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202 views

Infinite Universe and the big bang

OK, I was thinking of the big bang and how it relates to an infinite universe. If the universe is infinite is mass and there was a big bang, then at the big bang there was an infinite amount of ...
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If the universe is expanding, what is it expanding into?

If the universe is expanding, what is it expanding into? When the big bang happened where did it occur? When the big bang happened how did it occur? Where did the energy come from? Energy can not ...
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How can a quasar be 29 billion light-years away from Earth if Big Bang happened only 13.8 billion years ago? [duplicate]

I was reading through the Wikipedia article on Quasars and came across the fact that the most distant Quasar is 29 Billion Light years. This is what the article exactly says The highest redshift ...
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How do we know that space expanded with speed faster that a speed of light during big-bang inflation?

How do we know that space expanded faster than a speed of light in inflation? I have read this Phys.SE question, and it says that limit for faster than a speed of light is for matter and waves only. I ...
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Is it possible all matter in the universe emerges from nothing?

If the Universe is flat and the total energy of the universe can be zero (we don't know if it is, but many theorists support the idea, i.e. at BB initial conditions: t = 0, V = 0, E = 0) then is it ...
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Is energy since the big-bang still here in the present?

Based on the concept that energy can never be destroyed and is only transferred. Does it mean that energy since the formation of literally everything still here today?
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Searching for Big Bang Neutrinos

How is it possible to discover neutrinos from the big bang? Were the neutrinos emitted just before the big bang? Or at the same moment? If they moved outward in all directions, basically unhindered ...
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What has been proved about the big bang, and what has not?

Ok so the universe is in constant expansion, that has been proven, right? And that means that it was smaller in the past.. But what's the smallest size we can be sure the universe has ever had? I ...
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1answer
119 views

Can someone explain effects of time dilation on expansion of universe [duplicate]

I'm not a physics guy, but this is something I have always wondered about. If a clock flown by an object of high mass runs slower, what is the effect of this in regards to the density of the universe. ...
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57 views

How did the gravity of the particles/objects behave at the edge of the expanding universe moments after big bang?

During a very short time after the big bang, the universe must have had an edge of space-time which is very close to all the matter in the universe. The particles which are close to or on the edge ...
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Why doesn't the light from galaxies appear stretched? [duplicate]

Maybe it's my ignorance of astrophysics/cosmology, but I have been wondering this: Why do galaxies not appear stretched when we observe them? Assuming a galaxy that we observe is 100,000 light years ...
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1answer
164 views

Is there an absolute center of mass exist in the universe? [duplicate]

By the "absolute center of mass" I mean the center of all the matter that exists in a given moment. My friend asserted that today and it intrigued us very much but since we only have a CS degree and ...
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extreme heat to extreme cold (define the endstate)

Contemporary cosmology frequently has space temperatures just after the 'big bang' in the regions of millions of degrees and with inflation and expansion of the universe this is now down to a couple ...
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CPT theorem and annihilation of matter and antimatter after the big bang

Is the hypothesis that antimatter is moving backwards in time compatible with the hypothesis of annihilation of matter and antimatter after the big bang? It is said that the big bang should have ...
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2answers
255 views

Is there a consensus on the fate of our universe?

We all know that our universe is inflating from what is known as the Big Bang. However, will our universe continue to inflate at the current rate? Or after reaching a maximum size, will it collapse in ...
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1answer
113 views

The universe appears to have a lower bound in the time dimension, why not an upper bound?

The Big Bang looks like a lower bound to the "size" of the universe in the time dimension. Could it also have an upper bound, some furthest point in time from the Big Bang?
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When they say that the universe cooled after the big bang, where did the heat go?

Layman here, Stumbling through some physics stack posts and started reading the Wikipedia for the chronology of the big bang. In it, it states The very earliest universe was so hot, or energetic, ...
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Where does the light of the Big Bang come from?

I'm wondering whether the residual light of the Big Bang comes from one particular direction and what possibilities do we have to detect its position?
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What trajectory has the Cosmic Microwave Background radiation taken to get to earth?

I have a few related questions: Where is the CMB coming (emitted/reflected/remitted) from? When CMB hits the earth, is that the first thing those photons hit since they were emitted 400 thousand ...
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1answer
114 views

Infinite number of universes? Black holes are guilty? [closed]

I was thinking, if the space is infinite, what if there are infinite number of spaces, inside our universe? I mean, everyone knows that black holes exist, but nobody knows what happens when you get ...
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189 views

Seeing beyond the CMBR with neutrinos?

As I understand it, you can't see beyond the Cosmic Microwave Background Radiation because the plasma of the early universe was opaque to electromagnetic radiation. What if you had a "neutrino ...
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Where does the number “380,000 years for electrons to be trapped in orbits around nuclei” come from?

How does this number get calculated? About 380,000 years after the Big Bang the temperature of the universe fell to the point where nuclei could combine with electrons to create neutral atoms. ...
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The universe could have created itself? [duplicate]

So in this Youtube video http://youtu.be/ZjaaSUHG7Xo The guy says, around 6:15, that the total energy of the universe is zero because of gravitational potential (or something like that i dont ...
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1answer
76 views

Hot Big Bang vs. Big Bang

This should hopefully be a quick one. Is there any difference between the Big Bang Theory and the Hot Big Bang Theory? Around Cambridge I hear everyone using "Hot Big Bang Theory", for example ther ...
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1answer
87 views

A well-defined quantum probability in the beginning of the universe?

In mathematics or statistics, a well defined probability requires a large sample space. However, in the beginning of the universe, when the first quantum collapse happened, the sample space contains ...
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2answers
124 views

Could the universe have evolved WITHOUT the non-determinism of quantum mechanics? [closed]

(I'm going to make a few conjectures here - please answer the question in light of them as if they were true, even though of course they may be overly simplistic or wrong) Assuming that: the ...
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1answer
230 views

What is the difference between a low vs. high entropy plasma just after and before a singularity occurs?

Although it appears that the universe is not closed (since it is accelerating) I have been reading different websites on how the universe would look like if it was closed and the big crunch did occur. ...
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38 views

Cosmic Expansion - Why aren't we ripped off yet? [duplicate]

According to Hubble's law, the universe expands exponentially ever since the big bang. If the space-time expands, what effects does it have upon us, (1.Earth, 2.solar system and 3. Milky Way). ...
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77 views

How has the age of the Universe been derived from the observations made by the Planck mission?

The parameters of $\rm\Lambda CDM$ model have been determined to an amazing high precision from the measurements made by the Planck mission. In particular, the Hubble "constant" (the value of Hubble ...
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530 views

If the universe didn't expand faster than light, would our nights brighter like day?

There's a common QnA which has amused and inspired many kids: There are billions of Stars in the sky. If we combine lights received from all stars, wouldn't it beat Sun? Why is night dark really? ...
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2answers
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Big Bang Question

In the early Universe it it's believed that matter and anti-matter annihilated one another till there was but a remaining 1% left. In a matter/anti-matter collision, is there not an explosion of ...
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2answers
202 views

When was the cosmic background radiation in the visible spectrum?

From what I understand about the Cosmic Microwave Background Radiation is that it was from the big bang, and since space has streched and become bigger since then the wavelength of the CMBR has ...
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1answer
87 views

Understanding the cause of the big bang

Ok, as I understand the expansion of the initial singularity was caused by quantum fluctuations like the ones predicted by the Heisenberg Uncertainty Principle. But how can these fluctuations occur ...
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1answer
140 views

Black holes attracting each other [closed]

I was watching the tv series called, through the wormhole, and they mentioned a theory about multiple universes that are separated by a very small distance, like parallel membranes. They mentioned ...
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3answers
2k views

What is happening as our Universe is expanding? Is entropy increasing or decreasing?

Scientists say that entropy of our universe is increasing as it is expanding and our universe is cooling down gradually from the time of it's birth.If something is getting cooler and cooler then how ...
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3answers
123 views

Did “big bang” radiate light?

According to present day physics nothing existed before the "big bang", even space and time. But often in documentaries, the "big bang" is shown as a ball of light that exploded at some point. If this ...
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1answer
128 views

What Happens In Billions Of Years Time To The Universe? [closed]

I'm trying to imagine in my head what happens to the universe in ten billion years, twenty billion years, etc. I imagine that all mass in the universe turns to black holes, as when mass reaches the ...
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3answers
182 views

Is Space conserved [closed]

Can space be created or destroyed? Is space conserved? I am not asking for matter,energy and time. Its just a question about conservation of space PS: I am asking for what was there before big bang. ...
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2answers
100 views

Where did the universe get its initial momentum?

If, according to Newton's third law, forces come in pairs then what about the big bang? where did the universe get that initial push/momentum?
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374 views

Abundances of the light element of the Big Bang Nucleosynthesis

This question is related to the Big Bang Nucleosynthesis of light elements, more concretely I do not understand some features of the graph Why do the $^3$He and D abundances go down with ...
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1answer
83 views

Connection between the Big Bang and Black Holes [closed]

So... this is my first question here after a little while of lurking; so be gentle. I've been thinking lately about trying to wrap my head around the concept of spacetime and how it can be affected ...
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2answers
177 views

Time dilation at the Big Bang

At the time the Big Bang happened the matter had enormous density. According the GR (I may be wrong here) such density dilates time. If so, could it be that the time periods just after Big Bang which ...
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2answers
331 views

Did the singularity really existed in the begining of the universe?

I read in Hawking's brief history of time the following: The final result was a joint paper by Penrose and myself in 1970, which at last proved that there must have been a big bang ...
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144 views

If we say the universe is expanding, shouldn't it be expanding relative to something?

I don't understand, if everything in this world is relative to something else, then cannot we essentially say that nothing exists independently? We say that the universe is considered to be the ...
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The Helium mass fraction from the Big Bang Nucleosynthesis

In Perkin's book Particle Astrophysics (page 144): I do not understand how one comes to the following expression (the second equality with $r$) for the Helium mass fraction due to the Big Bang ...