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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How is finite energy spread wholly in the infinite universe

We all know that energy is never lost, but it transforms into another form. Doesn't that mean that energy is not unlimited? I mean, why is it that way if it was infinite? However, if energy is spread ...
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1answer
37 views

Quantum gravity- Vacuum catastrophe

Why does the predicted mass of the quantum vacuum have a very little effect on the expansion of the universe?
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0answers
15 views

Consequences of space-expansion in the Universe [duplicate]

Current theories about Universe dimensions and age put them - respectively - at about 90 G light-years wide and 13.8 G years old. To avoid implying that matter travelled faster than light, theories ...
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0answers
23 views

Senses in three-dimensional universe [closed]

Our senses perceive only a single threedimensional universe and the only non-physical entities we know are mental, are our thoughts in other dimensions?
3
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1answer
47 views

What is the mix of ordinary mass vs. ordinary radiating energy in the universe?

I have seen data showing that the estimated mix of dark energy in the universe is 68.3%, the mix of dark matter is 26.8% and the mix of ordinary matter is 4.9%1. However, within "ordinary matter," ...
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0answers
53 views

Is time infinite? [duplicate]

If time has a beginning, must it not exist for some amount of "time"? If not, it exists from the point when existence started and if there was ABSOLUTELY no existence there may not exist something ...
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1answer
131 views

Speed of light and current dimensions of the universe [duplicate]

I've seen several documentaries explaining that the diameter of the universe is currently estimated at over 90 billion light-years. And which that - in the face of the age of the universe being about ...
3
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1answer
389 views

Creation of a miniature universe?

I am not referring to the experiment being conducted at Lancaster University involving liquid helium and a magnetic field to build a marble sized representation of the early cosmos. My question is: ...
1
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0answers
80 views

Does Digital Physics imply Heisenberg's Uncertainty Principle? [closed]

I made the following observation which led me to believe that perhaps Digital Physics implies Heisenberg's Uncertainty Principle: Consider Noether's Theorem, which states that space-translation ...
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1answer
103 views

Did we get near Pluto with our current technology? [closed]

I was sent from Skeptic to here. We all know that NASA has successfully carried out the mission for getting near Pluto. More here. It is very difficult for me to accept that we already have the ...
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1answer
37 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, ...
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1answer
122 views

Can anyone explain the unit for rate of expansion of universe?

If you google for 'what is rate of expansion of universe' you get Space itself is pulling apart at the seams, expanding at a rate of 74.3 plus or minus 2.1 kilometers (46.2 plus or minus 1.3 ...
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1answer
49 views

Matter: how much of it exists?

This might be not a proper SE site, redirect it please to the correct if this resource is not a proper place to ask; I'm not a scientist/researcher, so may be I'm missing something well-known. My ...
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0answers
73 views

Do I need a particle to simulate a particle? [closed]

Edit TL/DR Is an assumption of the theory that the universe is a simulation that the simulating universe is fundamentally more complex than our own? The Long Version As a programmer, I find the ...
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2answers
100 views

If the universe is expanding will gravitational attraction eventually go to zero?

Let's assume that we prove that dark matter exists (after all, only about 4 percent of the entire universal mass is atoms, and 22% dark matter, 74% dark energy (I think I got the numbers right)). ...
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0answers
49 views

How does the Universe connect with other Dimensions? [duplicate]

I was wondering that if the Universe was expanding, what was it expanding into. I came up with a theory and I was wondering if there was any information to support my theory, if my theory is wrong ...
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4answers
958 views

How does the heat death looks like from inside the system?

As this answer points out, any human would first freeze rather than experience the heat death. However, assuming hypothetically that we could make some robot live at such low temperature (or even ...
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2answers
194 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 ...
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1answer
103 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 ...
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2answers
100 views

Why is universe expanding?

Okay, this question may sound silly: base on the observation Besides an expanding universe, would there be other possibilities? Would it be possible, say, there exists a fundamental repelling ...
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0answers
24 views

How redshift-space distortions affects baryonic acoustic oscillations

I have a question with BAO (baryonic acoustic oscillations) and RSD (redshift-space distortions). On large scales, Kaiser effect makes the observed radial separation of galaxies smaller then ...
0
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0answers
22 views

cosmology - Hubble parameter equation [duplicate]

I have a question. We know that the Hubble constant in the space is a constant, is the same everywhere, but it changes in time, so we don't talk of H0 but H(t). Is there a way, a formula to compute ...
1
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0answers
39 views

Cosmological Bulk Viscosity - is the universe a fluid?

I was trying to make heads of tails of both this paper and the press release about it. The scientists have used bulk viscosity (as opposed to shear viscosity) and popped it into a model and somehow ...
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1answer
63 views

Does new energy creation exist?

I know that basic physics states that energy cannot be created or destroyed, but why is that true? For example, one theory called Quantum Fluctuation states that 'normal' and anti energy is constantly ...
4
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1answer
73 views

Dark Civilizations? [duplicate]

I just read that maybe the dark matter could have dark forces. Hence, I wonder: dark atoms, dark galaxies, dark intelligent beings. Basically a parallel, interpenetrating universe. Is this ...
0
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1answer
28 views

Why do elements on the Binding Energy per Nuclear Molecule after Iron (most stable) even form?

So I was reading about the stability of elements based on Nuclear Binding Energy, and I saw that the 'Iron group' of elements were most tightly bound and hence most stable, and that is why the graph ...
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0answers
40 views

Do The Diameters of Distant Objects Seem to Get Larger?

So I'm curious about the dynamics of an expanding universe, My question may stem from misunderstanding so i'll outline what I know. When we view distant objects in the observable universe we are not ...
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1answer
41 views

Can pre-inflationary gravitational attraction affect objects after inflation?

According to inflation theory, the inflation itself took place at some short yet finite time after Big Bang, so there should be some gravitational interactions present before inflation, some objects ...
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3answers
135 views

Is the Universe being dragged into a singularity rather than expanding?

Recently I've read that the expansion of the Universe as observed is not exactly uniform as proposed by Hubble. Therefore is it possible that instead of space expanding in all directions all matter is ...
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2answers
41 views

How the mass is conserved during continuous expansion?

If universe is continuously expanding doesn't it contradict the fact that mass is conserved? Because if mass is conserved so how is universe expanding?
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0answers
22 views

Expansion of universe faster then speed of light? [duplicate]

Watching one of the shows on discovery channel, I got to know that during the starting phase of universe its speed should have been faster then speed of light. But then didnt einstein say that nothing ...
1
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2answers
71 views

What do we mean by the size of the universe? [duplicate]

Isn't it true that the concept of length exists only within the universe? Are we simply measuring the observable universe, that is to say, the spatial limits of our observation?
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1answer
54 views

Is there any experimental setup to test if we are Boltzmann brains? [closed]

I am not sure if this subject belongs to mainstream physics. my question is motivated by the fact that I am not sure we could ever test if we are Boltzmann brains. The same happens with string theory, ...
0
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0answers
22 views

What's the difference between cosmic time and conformal time? [duplicate]

When they say that the age of the Universe is about 13.7 billion years, they are giving the age in cosmic time, is that right?. There's this other thing called conformal time which I don't understand. ...
0
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0answers
17 views

Why can't our universe be spherical? [duplicate]

if we happen to follow the bigbang singularity hypothesis, when he explosion occured shouldn't it expand in all directions. Seemingly our universe shouldn't have any boundaries. I searched for the ...
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0answers
49 views

Is there any explanation for these objects apparently traveling faster than light? [duplicate]

This is from a documentary on the science channel: https://www.youtube.com/watch?v=RaELad94KZs
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2answers
56 views

What are the consequences of a non-computable universe?

I have seen that is is debated if the universe is digital, computable or non-computable. what specific consequence could this have in the format of the laws of physics? Or would that mean that we will ...
0
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1answer
61 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
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1answer
191 views

Obtaining a copy of Hawking's Ph.D thesis - Properties of Expanding Universes

Due to its popularity, I am interested to know the 4 chapter titles and topics covered in S.W. Hawking Ph.D, Properties of Expanding Universes. I also ask this because that thesis is hardly available. ...
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2answers
89 views

What's outside of the universe? [closed]

Assuming you found a way and managed to accelerate above light speed without disintegrating, and went to the edge of the universe, what would happen? Would you instantly explode due to the lack of ...
0
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2answers
493 views

Why does time exist? [closed]

So I have been thinking about some subjects and one of it involves time. And I tried writing a story/question on here to summarize the bigger picture but it's not going to happen it's too complicated ...
0
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0answers
13 views

Chemical potentials of SM particles at high temperatures

Recently I've heard the statement that chemical potentials of SM particles on $T > 1 \text{ GeV}$ are very small, so that Gibbs potential reduces to free energy. How to prove this statement? Does ...
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1answer
67 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
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3answers
78 views

Why is the ratio dark matter / normal matter bigger today than in the past? Is it the dark matter that increased or the normal matter that decreased?

These two pie charts clearly show that the ratio dark matter / normal matter is bigger today than it was in the past. But why? How is it possible? And does it mean that the amount of dark matter ...
1
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1answer
93 views

Traveling faster than the universe is expanding?

I was thinking, if the universe is space and time expanding, lets say in 3D (like a sphere). And it is doing that in a constant or not constant speed, there is a debate about that, never mind that but ...
1
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1answer
54 views

How can gravitational energy cancel out the rest energy of mass in the universe [duplicate]

I've heard that some physicists think that the net energy of the universe is zero. For this to happen, I would assume that the negative gravitational energy of a body ought to cancel out its rest ...
1
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0answers
69 views

Is there evidence that the universe truly is the entirety of “everything”? [closed]

This is a question that has popped in my head recently. Do we have any verifiable proof that the "known" universe truly is everything that is out there? I'm not talking about the multiverse theory ...
3
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3answers
326 views

What does the accelerating expansion of the universe mean about its end?

So we know that the expansion of the universe is accelerating.When we thought that the expansion of the universe was slowing down,we predicted that it would reach a plateaux and maybe reverse the ...
0
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2answers
63 views

We stretch as the universe does [duplicate]

Here's an idea I thought about; more of a thought experiment than anything: The universe is essentially the same as the universe 14 billion years ago, just stretched. However, all matter stretches ...
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4answers
789 views

Can a perfectly mathematically describable universe exist in a multiverse?

Assuming inter-universal (see here) travel is possible, can a perfectly mathematically describable universe exist inside a multiverse? If it could, would that mean that the multiverse is ...