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Questions tagged [universe]

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 the universe

The universe is a subjective term. It generally refers to either (1) all that obeys the known laws of Physics, or (2) all of (1) that is connected to each other by physical geodesics.

The study of the evolution of the is a subject of , which generally uses , though, in recent years, there has also been "String cosmology" and "Loop Quantum Cosmology", for instance.

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Is there evidence of a larger universe?

While mapping out the position, distance and movement of galaxies and quasars at the limits of the observable universe, have astronomers ever observed the motion of these object due to gravitational sources that may reside outside the limits of the…
Fergal
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How can stars make up 0.5% of whole universe?

I was reading Wikipedia article about universe and stumbled upon pie chart which represents what universe contains. It says that stars make up 0.5% of whole universe. I tried to find average distance between stars in the universe, but came to some…
user1880405
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Universe Expansion

I know the galaxies are moving away from us (faster and faster) but when we say the universe is expanding, is that really only pertaining to the galaxies expanding or is the space itself expanding? I know we don't yet know what the boundary is, but…
Sean Smith
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Can we see ALL of the observable universe?

Reading this wiki page about the observable universe, (and visible universe), implies that we humans, on this rock in the milkyway are seeing a static representation of the universe that is still effectively in the past. They're also saying that the…
giulio
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Can we prove that the universe is finite or infinite?

If I say that the universe is finite, how can you say with certain that I am wrong?
Garmen1778
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What happens when a photon reaches the "edge" of the universe?

As I understand it, there are several models for what the universe could look like from the “outside”. I don’t know if any of these are outdated, so if they are please tell me if they are. Expanding bubble. This model says the universe will never…
CoilKid
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What would be the implications of a Penrose Universe?

A Penrose tiling of a plane (note this not the same as a Penrose diagram) is a tiling that is "non-periodic", without "translational symmetry", meaning that you can't simply slide the pattern one direction or another and have the same pattern. This…
Hot Licks
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is the expansion of the universe observable at a smaller scale?

I have searched the network for a possible duplicate to this question but I have not found one particulary answering my question so recommendations are welcome. I understand that distances of celestial bodies from earth can be estimated by using…
Chimango Chisuwo
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Is universe expanding from inside or is being stretched from outside?

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 you have a sphere of nothing ( empty space ) and…
yaro014
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If the Universe reaches the state of heat death scenario, could it produce a new Big Bang?

So in heat death of the Universe time stops, matter is degraded, only quantum vacuum remains and the universe no longer expands? Aren't those conditions similar to what physicists say about the quantum field from which the Big Bang happened? So is…
Unixy
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Is this how a Universe could be created from nothing?

So this is a rather simplistic understanding but I want to know if it's fundamentally correct: We have nothing which we'll represent as $0$. Then we need a Universe which we can represent as any number of parts that sum to $0$ $$ 0 = -1 + 1 $$ In…
wooobie
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Why the mechanism of everything in the universe has a pattern?

why everything in the universe has a pattern which can be identified and understood to determine outcomes, properties, effects of almost everything. I am saying that couldn't the universe be like patternless, non-deterministic and chaotic. For…
BIDISH DAS
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Is universe infinite or not?

What do you guys think of Hawking's last paper "A Smooth Exit from Eternal Inflation?" https://arxiv.org/pdf/1707.07702.pdf according to him there's no such thing as infinite multiverses so he concluded there are many universes, although not…
SnoopyKid
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can a system with nested building blocks (atoms,cells) NOT be "fine tuned"?

Never mind whether the universe is "fine tuned" for anything in particular,just the idea that there is a nested hierarchy seems incredibly constraining on the outcome, and anything but accidental.
Joel Rice
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Center of the universe

Where is earth in relation to the center of the Universe? If we point a telescope in any given direction will we come up with the same distance to "as far as we can see"? Or can we see farther in some direction(s) as opposed to others. If the…
Steve Haman
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