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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Is the universe finite and discrete?

Is the universe finite, both in the sense of being a closed spacetime manifold, as viewed from the macro level, but also in the sense of being fully discrete and finite in all of its intricate quantum ...
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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 ...
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548 views

What is the inertial frame that explains the Foucault Pendulum?

I know that the Foucault pendulum rotation in relation to Earth is a proof that the object is inertial in relation to the distant stars. But what makes them more important than the Earth? Are they an ...
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166 views

What about the other side of the Black Hole

I was wondering if on the recieving end of a black hole can you see the photons being sucked in
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600 views

Universe Expansion as an absolute time reference

Why we call "constant" to the Hubble constant?, if the universe were really expanding then the Hubble "constant" should change, being variable, smaller and smaller..with "time". Other example/view ...
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170 views

Is it possible that portions of the universe are made of antimatter? [duplicate]

Possible Duplicate: Experimental observation of matter/antimatter in the universe I've heard a bit about the antimatter, matter inbalance. But I don't understand how it has been decided ...
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735 views

Do we have an idea about the amount of matter in the universe?

Do we consider the amount of matter in the universe to be "infinite"? Or do we have an idea about "how much" there is?
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Presence Of an Another Universe [duplicate]

Possible Duplicate: Experimental evidence for parallel universes Is there an universe similar to ours somewhere else, I mean I had heard from Einsteins theories that,actually when I am ...
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687 views

Experimental evidence for parallel universes

My idea of physics is that it is a collection of mathematical laws relating observables. And that one can perform alot of mathematical derivations on these laws to produce new laws between ...
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576 views

Entropy of an empty universe

After watching the first episode of wonders of the solar system, one question came up which is not explained. Bryan Cox says that ultimately the universe will be devoid of matter, so not even a ...
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Stephen Hawking says universe can create itself from nothing, but how exactly?

Stephen Hawking says in his latest book The Grand Design that, Because there is a law such as gravity, the universe can and will create itself from nothing. Is it not circular logic? I mean, how ...
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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 ...
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Why it is said that Universe is an isolated system?

I have read in many places "Entropy of an isolated systems never decreases" And as a corollary: "As Universe is an isolated system(I) then its entropy is constantly increasing(II)" I) ...
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Is the “far” universe expanding more quickly?

I'm reading this silly Time article: http://www.time.com/time/health/article/0,8599,2044517,00.html And they say "Even at its best, the 20-year-old telescope never had the acuity to peer so far into ...
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261 views

Expanding universe

If we know the universe is expanding in whatever direction we look, can't we reasonably estimate where the 'center' of the Universe is? Is the rate of expansions in all directions the same?
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993 views

How do we know the size of the universe?

Ok, from astronomical observations we can tell that the observable matter is separating - so rewind the clock about 13.7 billion years and it was all at a single point. However, how do we distinguish ...
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617 views

Alternative theories to the big bang?

Hey all, are there any theories out there on the origins (or infinite existence of) the universe beside the big bang that actually adhere to current scientific knowledge and fact?
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466 views

Is it possible for one side of the universe to “meet” the other?

I've variously heard the shape of the universe being described as multi-dimensional, like a helix or mobius strip, and super string theorem seems to say there are lots of universes all piled up next ...
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1answer
188 views

Gamma Ray Bubble at the center of our galaxy seen by Fermi Telescope

How could we measure high energy photons, whithout measuring them ? I can't understand how we can "see" those Gamma Ray Bubbles if they are not reaching here In this graph from Nasa you can see ...
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List of theories supporting origin of universe [closed]

Big Bang theory is widely accepted theory when it comes to origin of universe. What other really compelling theories are out there explaining/supporting the origin of universe. I know many people ...
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1answer
269 views

What happend with the light from all the galaxies visibles from an earth telescope?

Supposing it's possible to see some distant galaxies with an earth telescope, then, at the tip of the telescope lens there are photons comming from the distant galaxy... So, if I extend my hand in a ...
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5answers
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How many times has the “stuff” in our solar system been recycled from previous stars?

Is there a cosmologist in the house? I've got a basic understanding (with some degree of error) of some simple facts: The Universe is a little over 13 billion years old. Our galaxy is almost that ...
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8answers
616 views

Is relativity necessary for the existence of life?

If the universe didn't have the relativity principle, would it be able to support life? Life consists of very complicated organisms. The operation of these organisms depends on the laws of physics. ...
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3answers
396 views

Why did decoherence start in the first place?

We learn that the quantum wave function $\Psi$ collapses when it interacts with a classic object (measurement). My question is: Why are there classic objects after all, how did it all start? In a ...
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can a system with nested building blocks (atoms,cells) NOT be “fine tuned”? [closed]

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.
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Supermassive black holes with the density of the Universe

This question was inspired by the answer to the question "If the universe were compressed into a super massive black hole, how big would it be" Assume that we have a matter with a uniform density ...
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317 views

What is the name of the physical space enveloping all universes? [closed]

Please excuse my question, as i don't come from a physics background, but i was really wondering. Assuming we are in one of numerous universes which all have physical dimensions: What is the name of ...
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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 ...
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407 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.