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.

learn more… | top users | synonyms

3
votes
0answers
87 views

Does second law of thermodynamics imply the big bang?

Given that the second law of thermodynamics states that entropy always increases and the universe is currently not in a state of maximal entropy does that not imply that it must have started at a ...
2
votes
1answer
52 views

C&CP-Symmetry Violation in Baryogenesis

In cosmology, during the big bang; how does C-Symmetry violation allow for a greater number of baryons to be produced than anti-baryons in Baryogenesis, similarly how does CP-Symmetry tie into this?
9
votes
11answers
3k views

understanding time: Is time simply the rate change?

Is time simply the rate of change? If this is the case and time was created during the big bang would it be the case that the closer you get to the start of the big bang the "slower" things change ...
5
votes
2answers
281 views

Quantum entanglement and the big bang

Prior to the Big Bang all matter was compressed into a point of high density. Why isn't all matter already entangled?
4
votes
5answers
6k views

Does entropy increase or decrease as our Universe is expanding?

Scientists say that entropy of our universe is increasing as it is expanding and our universe is cooling down gradually from the time of its birth. If something is getting cooler and cooler, then how ...
-1
votes
1answer
50 views

Superstrings in the 10th Dimension [closed]

Physicists say that the superstrings vibrating in the 10th dimension are what create the subatomic particles that make up our universe and all other possible universes as well. If that is true, then ...
0
votes
2answers
220 views

I understand the Big Bang Theory (BBT), but how was the matter in the BBT created?

I understand the Big Bang Theory to consist of all of the matter being pulled into one great gravitational pull. such a great force that it expelled the matter out causing the idea of Red-Shift and ...
14
votes
2answers
2k views

When did the first carbon nucleus in the Universe come into existence?

I am a chemist with a passion for astrophysics and particle physics, and one of the most marvellous things I have learned in my life is the process of stellar nucleosynthesis. It saddens me how my ...
5
votes
2answers
453 views

Probability of spontaneous Boltzmann brain formation

I was reading through Scott Aaronson's notes (pdf), but I can't make sense of his discussion about Boltzmann brains on p61. Specifically the fact that it says: But the problem is worse. Since in ...
1
vote
2answers
114 views

If temperature is dependent on mass, how did the early universe have a temperature?

I am near the end of the book The First Three Minutes by Steven Weinberg. I am reading it in order to get a better picture of the early universe in the Big Bang model. But one thing I am having ...
0
votes
1answer
800 views

Stephen Hawking's theory of multiple universes [closed]

Is it correct to think that there are multiple universes? Does my thinking of having more than one big bang?
0
votes
1answer
381 views

Can space be created or destroyed [duplicate]

Wikipedia says It appears that space was created in the Big Bang, 13.8 billion years ago This seems a little off to me: can we say something has been created if there was no before it had ...
11
votes
3answers
4k views

Why can we see the cosmic microwave background (CMB)?

I understand that we can never see much farther than the farthest galaxies we have observed. This is because, before the first galaxies formed, the universe was opaque--it was a soup of subatomic ...
5
votes
1answer
625 views

Additional merits to Wetterich's “Universe without expansion” compared to standard cosmological redshift interpretation?

A recent news item in Nature promotes Wetterich's preprint "A Universe without expansion". All sounds very exciting but hard to judge for non-experts. As I understand from the Nature's article, the ...
0
votes
1answer
268 views

Origin of Universe [duplicate]

The universe is believed to have originated from absolutely nothing, and we know it is still expanding. Physics says "something can arise from nothing". I understand how mass and energy are related ...
5
votes
1answer
622 views

Doesn't dating the universe violate the concept of spacetime's inseparability?

It would seem that measuring an age of the universe from the big bang requires separating spacetime into a 3D coordinate system and a time track. I fail to understand why it is appropriate to take ...
25
votes
1answer
3k views

Why haven't we seen the big bang?

The Andromeda galaxy is 2,538,000 light years away, so if we view Andromeda from a telescope, we see Andromeda how it was 2,538,000 years ago. Now the diameter of the visible universe is 92 billion ...
0
votes
0answers
35 views

Best evidence for Big Bang? [duplicate]

Why is the existence of cosmic microwave background regarded as the best evidence of Big Bang (or Big Bang model?)?
1
vote
2answers
240 views

The Big Bang theory hypothesis

Is there a simple way to state the hypotheses of the Big Bang theory? I have the impression that the Big Bang singularity is merely a consequence of Freedman equations. Could somebody clarify what ...
2
votes
3answers
2k views

Why is the singularity of the Big Bang not considered to be the center of the Universe? [duplicate]

If the universe is expanding, then at some time in the past, it must have started from a single point but why this point is not the center of the Universe. Just like the singularity of black holes is ...
0
votes
1answer
65 views

General questions related to inflation of the universe

(i) We know that the universe is expanding. As it expands, something has to "fill in", even if it is vacuum. Isn't energy required for this? For creating new "dark matter"? But we can't get energy ...
1
vote
4answers
193 views

Has cosmic microwave background kept a constant frequency?

Has the frequency of CMBR changed at all since the beginning of the universe? Has it always had a microwave frequency or has the frequency increased/decreased over time or is the change due to factors ...
6
votes
3answers
368 views

What was the density of the universe when it was only the size of our solar system?

What was the density of the universe when it was only the size of our solar system? Did it approach neutron star density? Is it physically correct to even ask such a question?
0
votes
0answers
57 views

Is the Big Bang notion compatible with the flat space? (A problem with the **moment** of Big Bang, not with the place of it) [duplicate]

A passage from a paper: "If one imagines running the clock backward in time, any given region of the universe shrinks and all galaxies in it get closer and closer until they smash together in ...
-1
votes
2answers
129 views

If energy can't be created and can't destroyed [duplicate]

Then wouldn't be logical that all the energy in the big-bang-created-universe will equal to the energy that was released by the Big Bang? The sum is zero? Edit The cited dup is asking "Did the law ...
0
votes
2answers
54 views

Hubble Constant at understandable distances

If I had two tennis balls, one meter apart, at what velocity are they moving away from each other due to Hubble flow? (Assume they are in a zero G environment, and nothing impedes their movement.)
0
votes
1answer
102 views

Where is the universe expanding from? [duplicate]

It seems to be quite a common question to ask "what is the universe expanding into?" However I want to ask "where is the universe expanding from?" Is there a "centre of expansion" of our universe ...
2
votes
2answers
631 views

Can the Universe create itself?--Is Gott's Use of CTC in Planck time or less valid?

My question is the title of a 1991 paper by Richard Gott and Li-Xin Li: http://arxiv.org/abs/astro-ph/9712344 and is also a subject of his popular book, "Time Travel in Einstein's Universe" Ultimately ...
-1
votes
1answer
73 views

What proof do we have that space is expanding? [duplicate]

how can we really say that space is expanding when we cannot see the distant galaxies forming nor are the planets nearby newly formed, nor is anything expanding in size nor are we going far away? (...
0
votes
1answer
63 views

Is there a real and relevant relationship between Big Bang and dark matter?

Since the postulate of dark matter is based on the unexpected rotational velocity around the centre of a spiral galaxy, then it can be presumed that the Big Bang Theory is not relevant to the search ...
3
votes
3answers
445 views

Has anyone ever tried to formulate physics based on computer science or information processing?

Some physicists and university researchers say it's possible to test the theory that our entire universe exists inside a computer simulation, like in the 1999 film "The Matrix." In 2003, University of ...
1
vote
1answer
153 views

Age of the universe [closed]

Does the fact that the edge of our observable Universe contains information from the beginning of the Universe give us an ability to determine its age? The edge of our observable universe surely has ...
2
votes
2answers
216 views

Where did energy come from?

So it is my understanding that before the big bang there was a very small point that held all of the matter in the universe. My question is what form did energy of the universe take on when it was in ...
4
votes
1answer
158 views

When they say the universe was the size of a baseball about a billion billion billion billionth of a second

after the big bang. Does that means the observable universe was the size of a baseball, or does it mean the entire universe? I'm guessing it means the observable universe - as we really don't ...
2
votes
2answers
384 views

Where is all the Dark Matter? Theoretical Question

In my Physics Class we had to look into possible areas where Dark Matter could be "hiding." Such as Black Holes and so on. Dark matter really can be "seen" through its gravitational effects, and we ...
0
votes
1answer
136 views

Discrepancy problem in lithium?

Why is there a discrepancy between the amount of lithium-7 predicted to be produced in Big Bang nucleosynthesis and the amount observed in very old stars?
0
votes
1answer
307 views

Doesn't the Big Bang negate the law of conservation of matter? [duplicate]

I was watching Hawking (2004 film) and in the movie, Hawking has a sudden insight that all the matter and energy observed in the known universe may, in fact, have sprung out from nothing (singularity) ...
1
vote
4answers
276 views

Does big bang have really any justification while we are living within a huge chaos?

All the physicists already know that the n-body problem reveals chaos, so that the planets around the sun should undergo deterministic chaos with a Lyapunov exponent of the order of, say, $\frac{+1}{3....
0
votes
2answers
63 views

Is there a friction or retarding force in creating spacetime?

As matter and energy expand with the big bang, they create spacetime (or so I've been told). Is there any evidence that this creation of spacetime has a retarding force on the expansion? If not, ...
0
votes
1answer
63 views

What does inflationary theory explain which quantum entanglement cannot?

Introduction This is an honest question... I don't study inflationary theory extensively (This is an understatement) but I am lost as to why it was developed in the first place. Here is why: ...
1
vote
0answers
91 views

What happens if the big bang occurs once again?

according to string theory every universe is a large brane and big bang is a event which takes place when two branes collide with each other. if our universe brane collides with another brane there ...
0
votes
1answer
91 views

Is the center of the universe in another dimension?

If we live in a four dimensional world and when we try to find the center of the universe (where the big bang occured) we found that there is no apparent center, could that means that the big bang ...
26
votes
11answers
3k views

How can it be that the beginning universe had a high temperature and a low entropy at the same time?

The Big Bang theory assumes that our universe started from a very/infinitely dense and extremely/infinitely hot state. But on the other side, it is often claimed that our universe must have been ...
1
vote
0answers
76 views

Why did the universe have a low entropy at the big bang?

Sean Carroll, in his book "From Eternity to Here", asks the following question. Why did the universe have a low entropy at the big bang? in John Cramer version of the Wheeler - Feynman absorber ...
1
vote
0answers
40 views

Can quantum fluctuation happen outside space-time? [duplicate]

So far I know, quantum fluctuations happen inside the vacuum which resides in the space-time. So, can it happen outside space-time? Because, one proposition suggest, big-bang was result of some kind ...
9
votes
3answers
2k views

Is there a center of the Universe if the Universe is finite?

Ok, let me make myself clear. I saw all the other questions related to the question, but none of them actually asks the question the way I would put it and therefore no one answers it the way I want ...
0
votes
0answers
175 views

What evidence is there of a universe older than 13.8 billion years

I've read an analogy that finding iron-rich galaxies just 900 years after the Big Bang is like finding an old man in a crib in a nursery. We just recently found a supermassive black hole 12 billion ...
3
votes
1answer
184 views

Could Hyper-Massive Black Holes be due to Dark Matter in the Early Universe?

An interesting discussion started here: Is there a limit as to how fast a black hole can grow? I am curious if Thompson Scattering and Eddington Luminosity have the same effect on Dark Matter (or ...
0
votes
0answers
46 views

Infinite universe, big bang = no singularity? [duplicate]

If we traced an infinite universe back in time towards t=0(ish) would a singularity still be formed? Would the singularity be infinite in size? (To me it seems it would have to be) This reminds me ...
0
votes
1answer
69 views

Is the size of the universe directly related to its temperature? [duplicate]

The universe was at its hottest when it was at its smallest. As the universe expands, it gets cooler. Is the expansion of the universe the direct cause the cooling? I suppose it would be more clear ...