The universe refers to the cosmos; all of space-time and that which exists as part of it. Alternatively, it can refer to the observable universe, which only contains the part we can see. Questions tagged with this should ask about physics at scales the size of the universe or specific properties of ...

learn more… | top users | synonyms

0
votes
3answers
133 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 ...
1
vote
1answer
16 views

Single fundamental force at Planck epoch?

It is hypothese that after big bang when universe is a Planck time old, the 4 known fundamental forces used to be equal in strength or perhaps there existed single fundamental force before splitting ...
1
vote
4answers
1k 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 ...
-2
votes
1answer
63 views

Does universe calculate? [closed]

This is probably totally naive (philosophical?) question. I am not mathematician nor physicist so maybe it is quite dumb question too. IF universe does calculate, how does it cope with numbers like ...
0
votes
0answers
31 views

Is there an area of the universe observable from earth that is newer than the rest [closed]

If the big bang theory and expansion theory is correct, if we look from earth to the sky will we observe in a specific area newer galaxies than the galaxies we see in the rest of the observable sky? ...
0
votes
1answer
42 views

Are we really sure that the whole universe is expanding?

Haven't we thought about the possibility of only a region of the universe is expanding? What about space is expanding in this region and space is compressed in another region, that satisfies the ...
3
votes
1answer
61 views

The actual space curvature

What is the curvature of our physical space, according to the latest experimental data? I've found it somewhat difficult to find a definitive answer to the question, because the spacetime curvature ...
0
votes
1answer
52 views

How many electrons are there in the universe?

Someone on io9 estimated there were about 10^80 electrons in the universe, but I want to ask the Stack Exchange physics community.
0
votes
3answers
136 views

Can universe or anything be simulated with absolute accuracy? [duplicate]

In a simulation everything is known which makes any apparent random event a pre-calculated event. Taking that into account is it possible to simulate the universe with absolute accuracy in a way that ...
1
vote
1answer
87 views

How can the Schwarzschild radius of the universe be 13.7 billion light years?

So i was reading about Schwarzschild radius on Wiki and I found a interesting thing written there link. It says that the S. radius of the universe is as big as the size of the universe? How is this ...
0
votes
0answers
22 views

Why is the total energy of current universe conserved? [duplicate]

I began to think about this problem a long time ago and also asked some classmates as well, but none of them can give me a creative solution. I actually developed an original theory that our ...
-1
votes
0answers
20 views

Is there any possibility that space fabric was always there, only matter and time got created through the big bang?

We can't say there was nothing before big bang, we need to difine nothingness. What if the force in the big bang created time in order of accelerating material. Accelerating material which caused due ...
3
votes
1answer
53 views

Where else is there fire?

Apart from on Earth, where else does fire occur in the universe? I'd hazard a guess that it is quite rare for oxidation to occur naturally, could someone elaborate on this?
0
votes
0answers
21 views

Calculate Total Energy Of Universe [duplicate]

Physicist using $mc^2$ to calculate positive energy and $-MmG/R$ to calculate negative energy to calculate total nergy of the universe but I heard that one of them is relativly invariant and other ...
0
votes
2answers
71 views

Allowable spacetime deformations [closed]

What deformations are possible with spacetime? By 'deformation' I am referring to the kind of change in spacetime caused by the presence of a mass which deforms spacetime sufficiently to deflect ...
2
votes
2answers
72 views

How does a particular galaxy's apparent recessional velocity CHANGE as the universe expands?

By this I mean will the light from distant galaxies continue to show red shift (i.e. if you look at light from a particular galaxy now and in 10000 years time, the spectra will have been shifted ...
0
votes
1answer
57 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 ...
0
votes
0answers
41 views

Total Mass in Universe [duplicate]

Currently (2015), what is the total mass of the universe? How can we say with mathematical certainty that 69% is dark energy; 25% is dark matter; 5% is atomic matter; and 1% is neutrino, photon, and ...
0
votes
2answers
51 views

What would happen after the big crunch?

What is the aftermath of the big crunch?
0
votes
0answers
19 views

Higher dimension world possibility [duplicate]

Could it be possible that all of the unexplained phenomena (like uncertainty) in our 4D world might be originated from a higher dimension universe? If so, then of course we'll never observe the ...
2
votes
2answers
144 views

Is the universe 5 dimensional space-time or 4?

we've been told that in General Relativity (GR), matter tells space how to curve and space tells matter how to move. But my question is, if 3 dimensional space was curved by matter then it should be ...
0
votes
1answer
26 views

Will all the mass collapse in one place?

Will the stars, planets and everything in the universe collapse due to the gravity? Or does the constant expansion of the universe break that idea ? What will happen with the energy?
1
vote
0answers
60 views

Looking for more information about these two hypotheses

Big Lurch - This was one I read about in a special issue of Scientific American from 2014. It was explained as The Big Lurch is a theoretical scientific model suggested as one of the ...
-2
votes
1answer
49 views

Are all galaxies we see really our Milky Way? Any possibility?

There is a possibility for our universe to be the surface volume of a (higher-dimensional) hyperspace. So if this possibility is true,then is there also a possibility that the other galaxies we see ...
0
votes
1answer
41 views

Given an initial push, is work done on an object infinite in a hypothetical empty universe?

Consider a hypothetical empty universe containing a single object. Given an initial push, will the work done by the forever moving object be infinite?
1
vote
0answers
26 views

Is not the idea of a continuous universe and finite information density mutually exclusive?

As far as I understand, the universe is not divided into discrete units, but rather its continuous. This seems backed up by a quick search: Does the Planck scale imply that spacetime is discrete? ...
0
votes
0answers
113 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 ...
1
vote
2answers
68 views

Negative energy of universe

According to a little I have understood whatever we see in the universe is its postive energy and there is so an equal negative energy. Is this Negative energy the Dark energy? which is responsible ...
1
vote
2answers
153 views

Can a sufficiently large black hole be singularity-free?

This came to me after reading that a black-hole that has the mass of the observable universe will also have an event horizon that covers the observable universe. Since the definition of a black hole ...
-1
votes
1answer
50 views

Even the universe is infinite, it could keep expanding? [closed]

the study showed Cantor, that there are infinite types, the universe would be expanding as well as the possibility of Stephen Hawking. http://phys.org/news/2015-02-big-quantum-equation-universe.html
0
votes
1answer
49 views

How do we know the expansion of the universe is “of space” and not “in space” or “into space” or another less intuitive arrangement?

How do we know the expansion of the universe is "of space" and not "in space" or "into space" or another less intuitive arrangement? For example, what implicit and explicit assumptions underlie the ...
3
votes
3answers
135 views

Is it valid to apply Einstein's Relativity to scenarios involving expansion of space?

IIs it valid to apply Einstein's Relativity to scenarios involving expansion of space? For a practical example of this: Is it legitimate to speak of distant red-shift galaxies as experiencing time ...
1
vote
1answer
88 views

How can the universe by infinite when it has known start and finite time since? [duplicate]

Just watched the 'How Big is the Universe?' TV program and it indicated that the universe is believed to be infinite in size. They used an approach involving measuring the internal angles of ...
1
vote
0answers
80 views

Do past and future exist? [closed]

Ok, first thing I want to say is that I'm a layman. No high school math background whatsoever, so I'd be greatful if you could provide an explanation without equations. Now I'm quite interested in ...
-2
votes
1answer
69 views

What lies at the very edge of the expanding universe? [duplicate]

We all know that the universe is expanding at an accelerated rate and it might appear much like a soap bubble. That is where the phrase dark energy whose essence is unknown and which is thought to ...
0
votes
0answers
28 views

About a *center of the universe* [duplicate]

I understand that the history of our universe began with an explosion - the Big Bang. Now, I saw a comment in some old post, that "the universe has no center". Is that true? If there was initially a ...
0
votes
0answers
52 views

What does string theory and loop quantum gravity say about the Planck Epoch and anything before the Big Bang?

General Relativity is known to commit suicide exuberantly at the planck epoch, and is unable to say anything further, whereas string theory and loop quantum gravity breathe well under these ...
0
votes
0answers
34 views

Did spacetime curve infinitely about 13.7 billion years ago? [duplicate]

GR/Big Bang Model implies that there was a singularity about 13 billion years ago, in which all the matter and energy along with the observable universe (or perhaps, the entire universe) was ...
-1
votes
2answers
21 views

Is it better to define the observable universe as the universe?

This is somewhat triggered by this question: It's established that universal energy is not constant. But is the net change positive or negative? When I say entire universe, is that equivalent to ...
2
votes
1answer
50 views

Is universe expanding from inside or is being stretched from outside? [closed]

Just like in the title, Is universe expanding from inside or is being stretched from outside ? The way I see it from observations. There is a lot of talking about nothing and something. So lets say ...
1
vote
0answers
23 views

Cellular automata and time T

Reading around about various CA models I saw that there are even those who are following the track to provide a single mechanicist model of the universe. For example Gerard van 't Hooft claims that ...
4
votes
3answers
248 views

Is there an exact formal definition of the Universe?

I've read several articles about observable Universe, Universe and Hubble volume, including Wikipedia article and references on it, and I wondered: Is there a formal, rigorous definition in physics of ...
3
votes
1answer
103 views

What is meant with the statement: “the universe in infinite”? [duplicate]

I'd like to know what is thought of when saying the universe is infinite. I've read about what is meant when astronomers are speaking of a "flat" universe and I have read that its size is most likely ...
1
vote
0answers
29 views

Will any massless particle/object in the vacuum of space always travel at the speed of light? [duplicate]

The question as stated above, is "Will any massless particle/object in the vacuum of space always travel at the speed of light?"
-1
votes
1answer
69 views

Did light already experience death of the universe immediately after the Big Bang?

Let's suppose that I am on Point A with a light-beam launcher. My goal is to launch a beam of light to Point B, which is about 8,000 quadrillion light years away. My friend named Jack is at Point B ...
2
votes
3answers
157 views

Is simulating the entire universe possible?

Is it concievable that we may one day simulate the entire universe with every single particle, field and law of physics factored in? Can n number of particles (say the number of particles that make up ...
0
votes
2answers
63 views

Expansion of the universe a thermodynamic process or not?

Can the expansion of the universe be thought of as a thermodynamic process? If so, is it a closed system? Is it a reversible system?
2
votes
1answer
101 views

Question about universe expansion

In general relativity, we cannot determine the global structure of the universe (since it is not flat), therefore all measurements and observations are only meaningful locally. In particular, we can ...
-2
votes
2answers
34 views

Is it possible for the universe to be moving towards something, rather than expanding?

We all know that the universe is flying away from the Big Bang at speeds approaching or exceeding the S.O.L. However, is it physically possible for an object to be pulling the universe away as well?
0
votes
2answers
48 views

Was there a singularity before the Big Bang or after it? [duplicate]

I am slightly confused. Some say that the initial state of the universe was a singularity, and some say that before the Big Bang; there was a singularity. Can anybody elucidate?