The universe tag has no wiki summary.
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Conservation of Energy in the Universe [duplicate]
Possible Duplicate:
Is energy really conserved?
Why can’t energy be created or destroyed?
One of the laws of the universe that dazzles me the most is the law of conservation of energy. I ...
3
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3answers
196 views
If everything in the universe doubled in size overnight, would it be noticeable?
By my understanding, if everything doubled in size, such as the Sun and the Earth, and because the space in between them (which is nothing) can't expand, would the gravities greatly change and the ...
2
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1answer
235 views
Does the universe obey the holographic principle due to Stokes' theorem?
Does the universe obey the holographic principle due to Stokes' theorem?
\begin{equation}
\int\limits_{\partial\Omega}\omega = \int\limits_{\Omega}\mathrm{d}\omega.
\end{equation}
Can this ...
2
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2answers
464 views
The meaning of multiverse
A) I am intrigued by the multiverse theory as mentioned in Stephen Hawking's new book, "The Grand Design". According to his theory, one can have different 'universes' in one ultimate existence, a ...
5
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3answers
205 views
Is observable universe an explanation against Olbers' paradox?
First of all, let me tell you that I'm not a physicist but rather a computer scientist with a mere interest in physics at nowhere near a professional level so feel free to close this question if it ...
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1answer
138 views
Crucial Misconceptions about The Universe [closed]
So I am piecing together a school project on the numerous misconceptions of the universe, which I plan to "provide proof against them" with information from various sources (one of the main ones will ...
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3answers
220 views
Do new universes form on the other side of black holes?
I have four questions about black holes and universe formations.
Do new universes form on the other side of black holes?
Was our own universe formed by this process?
Was our big bang a black hole ...
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2answers
262 views
(Co)homology of the universe
In this post let $U$ be the universe considered as a manifold.
From what I gather we don't really have any firm evidence whether the universe is closed or open. The evidence seems to point towards it ...
2
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1answer
92 views
Fractal Cosmology and Misner's Chaotic Cosmology
I have a question pertaining to the ideas behind the considered homogeneity and isotropic nature of the universe (at a grand scale) versus the theory of a chaotic and anisotropy structure of the ...
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1answer
295 views
How does an inflationary universe solve the Flatness Problem, Horizon Problem and Monopole Problem? [duplicate]
Possible Duplicate:
What is the evidence for Inflation of the early universe?
I am reading some public science books on inflationary universe, e.g. The Inflationary Universe by A. Guth.
...
5
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2answers
225 views
Are we big or small?
How does the size of humans compare to the size of other objects in the universe? Are we among the relatively large or the relatively small things?
My very preliminary research suggests that the ...
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1answer
208 views
Is the structural similarity between atoms ( smallest) and universe (biggest) a conincidence. Or there can a reason for this beyond imaginations
Is the structural similarity between atoms ( smallest) and universe (biggest) a coincidence. Or there can a reason for this beyond imaginations.
It seems like, if one starts travelling from atoms... ...
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0answers
49 views
Why does $H_2$ form on such a long time scale?
If we were trying to figure out the time scale for a gas-phase reaction between two hydrogen atoms in a molecular cloud (which has density $~10^4/$cm$^3$), apparently the reaction would happen on a ...
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2answers
189 views
Did the universe always have 4 space time dimensions?
Is the dimensionality of spacetime in all usual models constant?
0
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1answer
78 views
Nature of an explanation [closed]
An explanation always refer to something earlier in time. Since A and B existed, then C had to happen because of universal laws of physics.
If "The Universe" is everything that exists and has ...
3
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2answers
180 views
How is it possible to come to a conclusion that Universe is a result of the Big Bang while we aren't able to observe the entire Universe?
-I'm not a religious person so this is not a denial. I'm just trying to understand the most fundamental topic about Universe.
-I know the Big Bang cosmological model is not a law but it's a theory.
...
2
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4answers
283 views
How was the universe created?
I do not know much beyond high school Physics. Thus, I am asking this question from almost layman's perspective:
What, as per the best of our existing knowledge and widely accepted among the ...
0
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0answers
50 views
Energy can't be created or destoryed? [duplicate]
Possible Duplicate:
Conservation law of energy and Big Bang?
If energy can't be created or destroyed then how did the big bang create energy? and if energy can't be created then does that ...
5
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2answers
250 views
What really is Spacetime?
What is a good definition on Space, Time and the most specific topic "Spacetime"? Because someone told me that spacetime is the foundation of the entire universe?
And also, Is it possible to create ...
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3answers
192 views
Is the cosmic horizon related to the Big Bang event?
The Universe expands according to the Hubble's law: velocity is proportional to distance.
There must be some distance, therefore, at which the velocity reaches the speed of light. This defines the ...
3
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1answer
93 views
What would happen in the final days of the universe?
I would like to know the stages of how the universe would end and what would happen and what the possible scenarios are.
I understand that eventually all the stars would burn out and that would ...
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3answers
438 views
Is the total energy of the universe constant?
If total energy is conserved just transformed and never newly created, is there a sum of all energies that is constant? Why is it probably not that easy?
2
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1answer
61 views
Why is that the space-time associated with the Earth is not shrinking?
If we apply the Friedmann Lemaître equation to the Universe, we find a critical density $\rho_c$ : if the actual density $\rho$ is under it, the Universe will continue to expand, if it is higher than ...
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9answers
740 views
Can a universe emerge from nothing?
If the Universe is flat and the total energy of the universe can be zero (we don't know if it is, but many theorists support the idea, i.e. at BB initial conditions:
t = 0, V = 0, E = 0) then is it ...
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2answers
79 views
Causal reconnection
Can causally disconnected regions join up again? For example the universe is expanding faster than light creating cosmological horizon, but what if something causes the expansion to slow down and ...
1
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1answer
405 views
is gravity always the weakest force [duplicate]
Possible Duplicate:
What does it mean to say “Gravity is the weakest of the forces”?
Strongest force in nature
It is usually taught that the gravitational force is the weakest ...
2
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1answer
122 views
Total momentum of the Universe
What is the total momentum of the whole Universe in reference to the point in space where the Big Bang took place?
According to my reasoning (and a bit elementary knowledge) it should be exactly ...
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2answers
404 views
how can galaxies collide if everything moving outwards
If the universe started from Big Bang and everything is expanding outwards and actually accelerating away from each other, than "How is it possible for two galaxies to collide as they all are moving ...
3
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3answers
596 views
Is there a finite amount of mass in the universe?
So, I'm not too physics savvy but I am curious to ask. Is there a finite amount of mass in the universe? or is there more and more being created from somewhere or something? If the universe is ...
2
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2answers
215 views
Maximum Possible Information in the universe?
I remember hearing about this in one of the programs in discovery science. The physicist claimed that the maximum possible information in the universe is (10)^(10^123) whereas the maximum possible ...
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8answers
2k views
Is time continuous?
I was making universe simulations, and I noticed that I implemented discrete time (the only type possible on computers). By that, I mean that I had an update function, that was called many times per ...
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2answers
396 views
Do we live in a world with 4 or more dimension?
A NOVA show have told the audience that we are live in 3 dimensional world, the world we lived in is compose by 3 element: the energy, matter, space. By the time Einstein have invented the ...
2
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2answers
345 views
What is the difference between parallel universe and multiverse?
What is the difference between parallel universe and multiverse? Is it parallel universe or universes?
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1answer
167 views
If the universe is infinite, shouldn't I already have been contacted by a time and space travelling doppelgänger?
If the universe is infinite, by virtue of chance it means that every possible configuration of matter must exist somewhere (according to this documentary).
Therefore, if we accept that the universe ...
3
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4answers
336 views
As the universe expands, why do some things stretch but not others?
I got into watching a video on Olbers' Paradox a few days ago, and from there read about the origins of the universe, its expansion, and so on... it's always fascinated me, but now something about it ...
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1answer
74 views
Cosmological constant of standard model of cosmology and observational data
I am curious whether the current Lambda-CDM model of cosmology matches well with observational data, especially expansion of the universe.
How well does Lambda-CDM defend its established status from ...
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1answer
271 views
Is the universe linear? If so, why?
Simple question, I'm trying to build a quantum memory system that utilizes the superposition principle to model specific phenomenon I am trying to predict, anyways, my question is this.
Is the ...
4
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4answers
834 views
Is spacetime discrete or continuous?
Is the spacetime continuous or discrete?
Or better, is the 4-dimensional spacetime of general-relativity discrete or continuous? What if we consider additional dimensions like string theory ...
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2answers
1k views
Size of universe after inflation?
Wikipedia states the period of inflation was from $10^{-36}$sec to around $10^{-33}$sec or $10^{-32}$sec after Big Bang, but it doesn't say what the size of the universe was when inflation ended. ...
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6answers
579 views
Does gravity slow the expansion of the universe?
Does gravity slow the expansion of the universe?
I read through the thread http://www.physicsforums.com/showthread.php?t=322633 and I have the same question. I know that the universe is not being ...
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11answers
493 views
Are there any theories that explain the very beginning of absolutely everything? [closed]
Of course there's the theory of The Big Bang, and there are theories on what caused The Big Bang, but what was the cause of the very first thing that ever happened? What started every
I also won't ...
6
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4answers
484 views
Is space unending?
Is the space unending, i.e it has no boundaries? If yes, how can a thing exist which is non-ending? Its impossible for me to imagine something like that. Secondly, if its not and has boundaries then ...
3
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1answer
116 views
Does cosmic expansion imply the possibility of the universe splitting in half; multiple big-crunches?
There is an event horizon where cosmic expansion leads to superluminal recession speeds for sufficiently distant objects -- the Hubble Volume.
1) Does matter beyond the event horizon affect us ...
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1answer
127 views
Do wormhole exits require matter? If not, would they change the edge of the universe?
As a layperson who watches way too many theoretical physics and astronomy documentaries, I've seen the folded-piece-of-paper analogy of wormholes a bajillion times. Usually they explain that black ...
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1answer
144 views
How fast was the universe expanding during the inflationary period?
Compared to how fast it is expanding in the post-inflationary period (now)
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1answer
111 views
A question about multiverse
I have a question that I would like to ask here since I'm not an expert or any near to that.
Actually I just came up with this question when I was watching The fabric of cosmos.
I couldn't find where ...
2
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1answer
177 views
How early can scientists detect that a deadly asteroid will hit planet earth?
With the advancements in science and technology, how early can scientists of the world detect that a certain asteroid will hit planet earth and cause damage? Are there any impact avoidance strategies ...
0
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4answers
377 views
Can the big bang be “light turning into space” at the edge of the universe?
The theory I've recently come to postulates that:
The volume of space filling the universe is finite and is constantly growing, thus the boundaries of the universe are constantly expanding.
The ...
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1answer
67 views
Does the movement of things in the universe will cease one day?
To start or change the movement, we need a force. This force, according to Newton's second law, is variation of quantity of motion from the object per unit of time.Therefore, if the variation does not ...
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2answers
240 views
Does the current acceleration of universe imply that our universe is open?
Does the current acceleration of universe imply that our universe is open?
If the universe is closed, from the Friedmann's equation, the acceleration of universe wouldn't be possible, would it be? (Of ...
