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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6answers
4k views
Why is there a scarcity of lithium?
One of the major impediments to the widespread adoption of electric cars is a shortage of lithium for the batteries. I read an article a while back that says that there is simply not enough lithium ...
13
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4answers
347 views
Does the universe have a center?
If the big bang was the birth of everything, and the big bang was an event in the sense that it had a location and a time (time 0), wouldn't that mean that our universe has a center?
Where was the ...
12
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6answers
676 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 ...
11
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4answers
200 views
Given that matter cannot escape a black hole, how did the big bang produce the universe we see today?
Extrapolation of the expansion of the Universe backwards in time using general relativity yields an infinite density and temperature at a finite time in the past.
If the matter contained within our ...
11
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3answers
1k views
How long will the Universe's hydrogen reserves last for?
I recently became really interested in learning about physics and cosmology, but I still know very little. Hopefully someone with more knowledge will be able to shed some light on my questions.
Here ...
10
votes
5answers
107 views
How large is the universe?
We know that the age of the universe (or, at least the time since the Big Bang) is roughly 13.75 billion years. I have heard that the size of the universe is much larger than what we can see, in other ...
9
votes
2answers
515 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 ...
9
votes
3answers
1k views
Where does matter come from?
I admit, it's been a few years since I've studied physics, but the following question came to me when I was listening to a talk by Lawrence Krauss.
Is there any knowledge of from where matter that ...
8
votes
3answers
1k views
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 ...
8
votes
9answers
757 views
Can a universe emerge 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 ...
8
votes
4answers
417 views
Did really everything begin with a state with very low entropy?
As emphasized by Penrose many years ago, cosmology can only make sense if the world
started in a state of exceptionally low entropy. The low entropy starting point is the
ultimate reason that the ...
7
votes
4answers
387 views
Are scientists missing the point with distant cosmic objects, or is it just me?
I was reading this article this morning:
http://www.bbc.co.uk/news/science-environment-13539914
Scientists have discovered a gamma-ray burst whose light has taken 13.14 billion years to reach Earth. ...
7
votes
2answers
132 views
Is it possible to look into the beginning of the Universe?
If we currently can look into some of the furthest stars, actually seeing the past
Isn't it conceivable that given enough distance we should be able to see
Parts of the Big Bang? If the Universe is ...
7
votes
4answers
1k views
Did time exist before the creation of matter in the universe?
Does time stretch all the way back for infinity or was there a point when time appears to start in the universe?
I remember reading long ago somewhere that according to one theory time began shortly ...
6
votes
4answers
413 views
Big Bang snuffed by a black hole?
Wasn't the density of the universe at the moment after the Big Bang so great as to create a black hole? If the answer is that the universe/space-time can expand anyway what does it imply about what ...
6
votes
3answers
166 views
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?
6
votes
1answer
191 views
Was the universe a black hole at the beginning?
Big bang cosmology, as far as I understand it, says that the universe was super hot and super dense and super small. It looks like that all the current matter, seen and unseen, were compressed to ...
6
votes
1answer
453 views
Alternative theories to the big bang?
Hey all, are there any theories out there on the origins (or infinite existence of) the universe beside the big bang that actually adhere to current scientific knowledge and fact?
6
votes
1answer
301 views
LHC Big Bang Temperatures
It's been claimed that the LHC's 14 TeV energy produces temperatures comparable to that which occurred very soon after the Big Bang. The well-known $E=1.5kT$ formula from classical statistical ...
5
votes
4answers
109 views
Why is there still radiation left from the Big Bang now? [duplicate]
Possible Duplicate:
Why can we see the cosmic microwave background (CMB)?
We all have seen evidence of radiation left from the Big Bang, but how is it still detectable? Why didn't it ...
5
votes
2answers
109 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 ...
5
votes
4answers
843 views
Did spacetime start with the Big bang?
Did spacetime start with the Big Bang? I mean, was there any presence of this spacetime we are experiencing now before big bang? And could there be a presence/existence of any other space-time before ...
5
votes
1answer
1k views
How can something finite become infinite?
How can the universe become infinite in spatial extent if it started as a singularity, wouldn't it take infinite time to expand into an infinite universe?
5
votes
1answer
360 views
Do all the forces become one?
Were the forces of nature combined in one unifying force at the time of the Big Bang?
By which symmetry is this unification governed?
Are there any evidence for such unification of forces?
Has ever ...
5
votes
3answers
215 views
Is the cosmic horizon related to the Big Bang event?
The Universe expands according to the Hubble's law: velocity is proportional to distance.
There must be some distance, therefore, at which the velocity reaches the speed of light. This defines the ...
5
votes
3answers
198 views
Creation of matter in the big bang
I appreciate your patience to my neophyte question. I am working on my dissertation in philosophy (which has nothing or little to do with physics) about the "problem of naming." Briefly what I am ...
5
votes
4answers
738 views
How do we know the size of the universe?
Ok, from astronomical observations we can tell that the observable matter is separating - so rewind the clock about 13.7 billion years and it was all at a single point.
However, how do we distinguish ...
5
votes
1answer
586 views
on causality and The Big Bang Theory
With the notion of causality, firmly fixed by GR, we derived the concept of a singular point from where space-time begun. Causality alone gives us the possibility to talk about a known past (i.e. ...
5
votes
2answers
258 views
What really is Spacetime?
What is a good definition on Space, Time and the most specific topic "Spacetime"? Because someone told me that spacetime is the foundation of the entire universe?
And also, Is it possible to create ...
5
votes
1answer
31 views
What would the universe look like if it started out without any irregularities?
(Warning! Newbie question coming up!)
Background
As seen on this picture of the cosmic microwave background (take from the Wikipedia entry on the very same topic) there exists irregularities in the ...
5
votes
5answers
1k views
Conservation law of energy and Big Bang?
Did the law of conservation of energy apply to the earliest moments of the Big Bang? If so, what theoretical physics supports this?
I hear that Einstein's theory of relativity disputes the law of ...
5
votes
4answers
1k views
What is our location relative to the Big Bang?
Given what we know about space, time and the movement of galaxies, have we or can we determine what our position is in relation to the projected location of the Big Bang? I've read some introductory ...
5
votes
1answer
159 views
Early time in the Big Bang
I am not a physicist, so I would really appreciate using a simple language for the explanation of my question. From what I understood at the early Big Bang the four fundamental forces were unified to ...
5
votes
5answers
2k views
Why was the universe in a extraordinarily low-entropy state right after the big bang?
Let me start by saying that I have no scientific background whatsoever. I am very interested in science though and I'm currently enjoying Brian Greene's The Fabric of the Cosmos. I'm at chapter 7 and ...
5
votes
1answer
157 views
Looking for review articles on big bang nucleosynthesis
Can someone point to a good review article covering contemporary developments in big bang nucleosynthesis, beyond what's covered in Kolb and Turner's The Early Universe? Thanks.
5
votes
3answers
222 views
Why the red-shift of distant galaxies is considered to be the effect of expanding spacetime?
Why it's not explained just by Doppler redshift caused by faster movement of those galaxies billions of years ago when that light was emitted?
Would the speeds of the galaxies necessary for Doppler ...
5
votes
2answers
118 views
Why does the homogeneity of the universe require inflation?
They say inflation must have occured because the universe is very homogeneous. Otherwise, how could one part of the universe reach the same temperature as another when the distance between the parts ...
5
votes
3answers
446 views
How can a quasar be 29 billion light-years away from Earth if Big Bang happened only 13.8 billion years ago?
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 ...
5
votes
4answers
261 views
Do new universes form on the other side of black holes?
I have four questions about black holes and universe formations.
Do new universes form on the other side of black holes?
Was our own universe formed by this process?
Was our big bang a black hole ...
5
votes
1answer
105 views
Which came first, movement or heat?
According to my measly understanding of the universe, when particles hit one another, some of their kinetic energy is transformed into heat. But when we heat particles (for instance, putting a bucket ...
4
votes
5answers
3k views
How can something happen when time does not exist?
I saw this documentary hosted by Stephen Hawkins: www.youtube.com/watch?v=WQhd05ZVYWg
And if I didn't get it wrong, it says that there was no time before the big bang, time was created there.
So how ...
4
votes
2answers
123 views
Shouldn't LHC have used $p\bar{p}$ collisions, instead of $pp$ collisions, to study baryogenesis?
Baryogenesis is the physical process(es) that produced baryon antibaryon asymmetry in the early universe. That means, the laws that governed the bigbang was baryon-antibaryon symmetric.
On the other ...
4
votes
3answers
127 views
If the universe started again with exactly the same conditions… would it be the same?
Sorry if this is a basic question but I can't find anywhere to ask else to ask it:
If the universe was created again and exactly the same conditions where in place at the beginning, would everything ...
4
votes
4answers
105 views
Could there be more universes?
In the documentary: "Curiosity - Did God Create the Universe (on YouTube)", theoretical physicist and cosmologist Stephen Hawking states that time did not exist before the big bang.
The first ...
4
votes
4answers
457 views
Question regarding the validity of the big bounce
I have several questions regarding the "big bounce" theory. It appears to be popular among LQG researchers. My questions are as as follows.
1) How one reconciles it with the fact that it is now ...
4
votes
2answers
105 views
Was the singularity at Big Bang perfectly uniform and if so, why did the universe lose its uniformity?
Am I right in understanding that current theory states that Big Bang originated from a single point of singularity?
If so, would this mean that this was a uniform point?
If so, as the universe ...
4
votes
3answers
75 views
Does the expansion of the universe soon after the Big Bang affect the amount of time that light takes to reach us?
If faster than light travel is impossible, how is it that light emitted from matter so close together in the time soon after the Big Bang is only now just reaching us? I would assume that there would ...
4
votes
1answer
24 views
Light years and redshift from our point of view. How can we see it?
So I was reading about GN-108036 this morning and for some reason I thought of something which I can't quite wrap my head around and make sense of. It's early morning so maybe coffee hasn't kicked in ...
4
votes
2answers
192 views
How is it possible to come to a conclusion that Universe is a result of the Big Bang while we aren't able to observe the entire Universe?
-I'm not a religious person so this is not a denial. I'm just trying to understand the most fundamental topic about Universe.
-I know the Big Bang cosmological model is not a law but it's a theory.
...
4
votes
0answers
55 views
Why didn't a black hole form right after the Big Bang? [duplicate]
Why didn't a black hole form right after the Big Bang and the universe contract towards a singularity?
