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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54
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6answers
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What is known about the topological structure of spacetime?

General relativity says that spacetime is a Lorentzian 4-manifold $M$ whose metric satisfies Einstein's field equations. I have two questions: What topological restrictions do Einstein's equations ...
14
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6answers
5k views

Why is the mapped universe shaped like an hourglass?

I've watched a video from the American National History Museum entitled The Known Universe. The video shows a continuous animation zooming out from earth to the entire known universe. It claims to ...
-2
votes
1answer
153 views

Four-dimensionalism vs energy economy

Four-dimensionalism claims that the universe is basically one huge space-time worm and that everything exists at once (however you want to say that since "internal time" is then just another ...
1
vote
1answer
430 views

What if the Universe is made of recursions? [closed]

What do you guys think of Scott Adams' theory that the Universe might be made of recursions, created by observation? I find it fascinating but have no strong opinion yet if it makes sense.
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7answers
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Does Quantum Physics really suggests this universe as a computer simulation? [closed]

I was reading about interesting article here which suggests that our universe is a big computer simulation and the proof of it is a Quantum Physics. I know quantum physics tries to provide some ...
10
votes
6answers
4k views

Does anything exist in the intergalactic space?

I am a part time physics enthusiast and I seldom wonder about the intergalactic space. First, it is my perception that all(almost all) the objects in the universe are organized in the forms of ...