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 ...

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2
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1answer
18 views

Can a theoretical object exist as such that its mass overcomes gravitational collapse

A daydream the other day led me to the question if "a universe filled with water (or any other substance for that matter), instead of being mostly void" could exist within the rules of our current ...
1
vote
1answer
51 views

Many questions about expanding of the space

Sorry if my grammar is a bit off. But I have few questions about space and its expansion. If space expands faster and faster all the time, will there be a time when we cannot see further than "hubble ...
3
votes
1answer
56 views

How could the universe be hyperbolic if hyperbolic space isn't symmetrical?

In the 2-D projections of the shape of the universe shown here, we see that the flat universe and the spherical universe are perfectly symmetrical, so any triangle drawn anywhere on them will be the ...
0
votes
1answer
50 views

Big Bang not really the beginning of a completely new universe? [on hold]

From what I know about the origins of the universe and the big bang, it is stated that it all started from an intensely hot and dense mass. This sounds like a singularity to me, which means a black ...
0
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1answer
60 views

In a static bounded universe, what happens to particles that hit the edge?

Consider a flat universe. The metric tensor is $$g_{\mu\nu}=\left(\begin{array}{cccc}-1 & 0 & 0 & 0 \\ 0 & 1 & 0 & 0 \\ 0 & 0 & 1 & 0 \\ 0 & 0 & 0 & ...
5
votes
4answers
2k views

Does physics claim that every possible world has or will exist? [closed]

Has physics proven that every possible world has or will exist? Someone on-line, who actually seems fairly intelligent, but troll-ish, claims that there is good reasons for it, not from any ...
-1
votes
1answer
65 views

What is a simple explanation to the fact that the universe is expanding? [closed]

How can we prove that the expansion of the universe is actually occurring to highschool children?
1
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1answer
45 views

Can the curvature of the Universe be a function of time?

Apologies for the repetition here, but can our Universe experience (either physically or mathematically) non-constant curvature that is a function of time?
-7
votes
1answer
60 views

If a being was able to swallow itself, where would it go physically? [closed]

if a being was made from a special type of material that allowed it to stretch and was very flexible, if it were to swallow itself, where wold it go. I mean the physical aspects of it since it wont be ...
-1
votes
0answers
21 views

Deterministic universe vs Law of Conservation of information

Simply put Can Law of Conservation of information hold along side presence of truly random events in the universe? Say for example if event of a particle decay is a really truly random process which ...
0
votes
1answer
38 views

One particle infinite manifestation universe [closed]

I know how non-intuitive everything related to quantum physics is and I was thinking on some very unintuitive things like John Wheeler one electron universe theory ...
-3
votes
0answers
24 views

What's the consensus on the block universe? Is time frozen? [duplicate]

What's the consensus view on the block universe? Is time frozen? Do the past and future exist? Was Einstein right when he said, “People like us, who believe in physics, know that the distinction ...
1
vote
0answers
32 views

Curisioty about universe [duplicate]

I am a bachelor student and I have a question going round my mind about the universe. Every one says that the universe is ever expanding and it is also said that the vast possible space is also the ...
1
vote
1answer
77 views

What would happen if there was a fifth fundamental force? [closed]

Preceding this question, as a student of physics, my knowledge of theoretical physics is somewhat limited. So I came across this article, which posited what the universe would be like if three ...
1
vote
3answers
60 views

What evidence is there that universe will not shrink again?

There are theory that universe eternally expanding and shrinking, so that every event and our lives will repeated again. At the other hand some scientists thinks that it will not shrink again because ...
-1
votes
1answer
53 views

Equation for everything?

Suppose, I throw a ball and it bounce. If we observe it from the time of it hitting the ground, we can see it moves due to the initial velocity it had and the interaction it had with the ground. We ...
4
votes
1answer
44 views

Did our Universe experience a curvature dominated phase?

So, my question is simple: did our Universe experience a curvature dominated phase? Or, rather, could our Universe have experienced a curvature dominated phase? This seems quite shruggish, at first ...
-4
votes
1answer
35 views

Put energy into void [closed]

what happens when you drop matter or energy of any type into the void , by void I mean a space of absolute emptiness with nothing more than darkness and total absence of every kind of energy , ...
1
vote
1answer
57 views

Rotational relativity? Is there an universal frame of reference for rotation?

So, there is obviously no such thing as an universal frame of reference for velocity. According to the relativity theory, there is no difference between two observers moving with respect to each ...
11
votes
1answer
2k views

Is the question: 'Is our universe the inside of a black hole?' meaningful? [duplicate]

By meaningful I mean experimentally falsifiable.
1
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0answers
26 views

How is it possible to have such massive black holes? [duplicate]

Recent observations discovered really massive black holes, up to $20-40$ billions Solar masses. Now, according to an recent study and various computer simulations (I'm sorry, I don't have any ...
0
votes
1answer
51 views

Rate of change of temperature of the Universe

Temperature of the whole universe is about 2.7K base on the wmap satellite. I know that temperature has to decrease to time and I have difficult time finding references for rate of change of ...
1
vote
1answer
45 views

Expanding space and red shift

Assuming space is really expanding - Due to expanding space, distant galaxies are supposed to be moving away from us. When light leaves a distant galaxy, it's wavelength is red shifted to begin with ...
-4
votes
1answer
66 views

Creating something from nothing [closed]

Space is NOT NOTHING this is space in Cantorial Set Theory: S = {(x, y, z) | r² = x² + y² + z² } But NOTHING in set theory has a special symbol and it is written like this: Ø = { ...
2
votes
1answer
73 views

Why can't our expanding universe be an imploding universe that appears expanding relative to us? [closed]

Galaxies moving away from us is our proof of an expanding universe. However, if the universe was contracting towards a black hole we would see a galaxy ahead of us accelerating faster towards that ...
1
vote
1answer
56 views

What are the pieces of evidence that universe is expanding? [duplicate]

Do we have any other evidence other than red shift? Is anyone trying to disapprove inflation? Also, can red shift occur because of large distance, not only because two objects are going farther from ...
0
votes
1answer
70 views

What happens to spacetime in a universe with no clocks?

For example, in the far future when all matter has been absorbed into BHs which have evaporated leaving only photons.
5
votes
1answer
67 views

Does the Universe spin? [duplicate]

Maybe it's a stupid question, so I will delete it if it will receive too many down votes but.. I was wondering about the Universe, and the fact that We know it's expanding; We don't know if it has ...
-1
votes
1answer
65 views

Wouldn't it take an infinite amount of time to create an infinite universe? [duplicate]

I have heard many people say that the universe is possible infinite. But, if it takes time and energy to create bodies such as planets and stars and the universe has only existed for 13.7 billion ...
-2
votes
1answer
29 views

Is it possible to detect strong light rays before they hit us? Can those light rays be strong enough to wipe out life on earth? [closed]

Our observable universe is continually expanding, so as soon as a powerful source of light is within our horizon, it should be visible from earth. I know that light weakens with distance but Would ...
3
votes
1answer
52 views

Is the cosmological horizon expanding faster than space itself?

I read that the rate of expansion of the universe is still a mystery. But if it's actually decelerating, wouldn't it mean that our cosmological horizon is expanding faster than space, and that one day ...
-2
votes
1answer
39 views

Does our Universe reside in the smallest particle? [closed]

I do not know where to ask this question in the first place, but I think here would be a start. Is there a possibility that if we go inside the smallest particle (which we have not discovered yet; ...
0
votes
0answers
26 views

What would happen if another big bang occurred at the centre of the current universe? [duplicate]

If another Big Bang occurred now, at the centre of our universe, what would happen? As the rate of expansion is increasing, the two "layers" (if there were any) would never meet, in which case, would ...
0
votes
0answers
55 views

Scale factor of the universe

Do we impose that the scale factor $a(t)$ of the Universe is a continuous function? Or there is a physical meaning? Usually in physics we define functions to be continuous, such as the velocity of a ...
0
votes
2answers
74 views

How is the universe flat?

I have real trouble visualising what is meant by the descriptor 'flat' when referred to the shape of the observable universe. Which one of the below is more accurate? a) It is flat in a 2D way, like ...
1
vote
0answers
19 views

Rate of expansion of universe during big bang [duplicate]

We say big bang was the explosion not in the space but of the space itself that took place in a fraction of seconds. Speaking practically, we say the universe has no edge and is infinite. If the ...
4
votes
5answers
160 views

Is the universe bounded?

As I understand it nobody can pinpoint an objective "center" of the universe nor "where" the Big Bang happened. It seems the observable universe is limited by our event horizon at some 14 billion ...
0
votes
3answers
89 views

Universe expansion and general relativity [closed]

If the universe is expanding faster and faster, won't we reach a moment where the general relativity will make the mass so big, that the universe will have to decrease its acceleration?
0
votes
0answers
20 views

Light from the big bang [duplicate]

Considering that the Big Bang all started from a single point in space time, and the light emitted from it has been spreading outwards in all directions ever since, how do we, from earth, see the ...
0
votes
2answers
94 views

What is the amount of dark energy in the Universe, in joules?

I'm toying with an idea, and need absolute amounts of dark energy. I'd also like the same for dark matter. If these values are not estimated, why not?
0
votes
1answer
41 views

Could the universe really be expanding at a constant rate? [closed]

I was just thinking, sorry if this idea is idiotic, but since we know galaxies move away from each other at an accelerating rate, could this be due to a weakening gravitational force between galaxies? ...
3
votes
0answers
63 views

Multiple Intersecting Universes [closed]

I am not a relativist or cosmologist, so this is very qualitative: I imagine a pair of universes, where each has two spatial dimensions (plus time), embedded in a 3-D (plus time) space, and these ...
-1
votes
2answers
92 views

Is there a natural source of Antimatter in this universe?

I was just asking if there is an natural source of Antimatter in this universe capable of creating simple molecules/compounds? So, any good answers?
3
votes
1answer
85 views

Universe vs Multiverse. Time and Space

Wikipedia defines a multiverse as a hypothetical set of finite and infinite possible universes. Similarly, it defines the Universe is as "all of time and space and its contents". On the surface, ...
2
votes
0answers
57 views

Where does all the energy in the universe come from? [duplicate]

The principle of conservation of energy says that all energy in a system will remain the same. It can just be transformed. The universe contains a huge amount of energy, but where did it come from? ...
3
votes
2answers
178 views

Gravitational waves, tides and the end of universe

Is tides proof of gravitational waves with low frequency? According to Wikipedia, In physics, gravitational waves are ripples in the curvature of space-time which propagate as waves, travelling ...
0
votes
2answers
86 views

Expansion of the Universe [duplicate]

At what speed is our solar system expanding, and if it is, why don't the positions of the sun and planets change, or grow farther apart? Why is the Big Dipper still where it is?
22
votes
8answers
4k views

Entropy is…disorder?

As I read somewhere, it said that the universe is heading toward disorder a.k.a entropy increasing. Now as far as I know from the second law of thermodynamics it states that entropy is indeed ...
0
votes
0answers
27 views

Chaotic inflationary model - bubble inside bubble

I was reading a bit about Prof. Linde's chaotic inflationary model of expansion of universe. He has mentioned about 'bubbles' of space time expansion. But no one has spoke about bubbles inside ...
3
votes
5answers
278 views

Could the universe be accurately simulated with an infinitely powerful computer? [duplicate]

This would mean that every event happens because of what has hapened before it and there is no randomness factor. At a microscopic level, the motion of atoms is a result of the motion of other atoms ...