The universe tag has no wiki summary.
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According to Hubble's Law, how can the expansion of the Universe be accelerating?
Scientists today think the expansion of the universe is accelerating.
According to Hubble's law, objects further away are moving faster than objects closer to us. The further away an object is, the ...
5
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1answer
32 views
Correlation between speed, distance, mass, etc between a planet and a star (or moon and planet)?
While playing around with some little scripts, generating solar systems, I started to wonder about the correlation between the different objects. Up until now, distance, mass, size and speed are ...
12
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2answers
230 views
Dumbed-down explanation how scientists know the number of atoms in the universe?
It is often quoted that the number of atoms in the universe is 10$^{70}$ or 10$^{80}$.
How do scientists determine this number?
And how accurate is it (how strong is the supporting evidences for ...
5
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4answers
261 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 ...
0
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1answer
87 views
Is time slowing down and disappearing from the universe instead of the expansion of universe? [duplicate]
Are we fooled into thinking that expansion of the universe is accelerating, when in fact, time itself is slowing?
Or if dark energy does exist?
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1answer
72 views
Were the numbers too created at the time of Big Bang? [closed]
It is said that everything was created at 'Big Bang', including mass, electric charge, time and even empty space. All of these have specific properties (like gravitational constant has a specific ...
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4answers
387 views
Are scientists missing the point with distant cosmic objects, or is it just me?
I was reading this article this morning:
http://www.bbc.co.uk/news/science-environment-13539914
Scientists have discovered a gamma-ray burst whose light has taken 13.14 billion years to reach Earth. ...
1
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1answer
43 views
Universe with ZERO Fundamental Forces
Warning: I am not a physicist so please excuse my naivety!
As you all know, physicists think that there exist four fundamental forces.
Would a universe with zero fundamental forces be possible, at ...
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1answer
47 views
Shrink where mass is present theory
This is a philosophical question first and foremost. Let's pretend that space is static e.g. it has a finite size. Let's assume that there are two bodies for example two solid spheres. Now if space ...
0
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1answer
60 views
What is the wave length of the entire universe?
In quantum physics, particles are also waves. Larger particles have shorter wave lengths, and macroscopic objects have extremely short wave lengths so that the wave aspect can be ignored, and ...
2
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2answers
77 views
Questions about the Jeans length
I have a couple of questions about the Jeans length. Suppose the universe has a homogeneous energy density, except there's a spherical region that is overdense.
I understand that if the region is ...
1
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1answer
46 views
Non-isolated universe and arrow of space
Could you please help me to understand two statements in physics:
1) Universe by definition is an isolated system.
But universe expands, space pours into universe, space (vacuum) has zero-point ...
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4answers
2k views
Why is the universe so big?
The Universe is approximately 13.7 billion years old. But yet it is 80 billion light years across. Isn't this a contradiction?
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7answers
1k views
How many bits are needed to simulate the universe?
This is not the same as: How many bytes can the observable universe store?
The Bekenstein bound tells us how many bits of data can be stored in a space. Using this value, we can determine the ...
5
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4answers
1k views
Infinite universe - Jumping to pointless conclusions
I watched an episode of thee BBC Horizon series titled 'To infinity and beyond'.
In this program a number of respected physicists and mathematicians were talking about the nature of infinity and an ...
0
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4answers
331 views
Is there anything physically infinite?
I can't think of a single thing that could be infinite.
Because the universe is expanding, isn't it? But there is an ever-changing barrier, so why could there be anything infinite, both ...
6
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1answer
155 views
Our Universe Can't be Looped? [duplicate]
With reference to the Twin-Paradox (I am new with this), now information of who has actually aged comes from the fact that one of the twins felt some acceleration. So if universe was like a loop, and ...
1
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2answers
99 views
Is it possible that universe might not be speeding up expansion?
I'm not sure but I was thinking of galaxies shrinking with time while still moving apart from each other at almost a constant speed or less (i.e: uniform/slightly decelerating expansion). This may ...
0
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1answer
86 views
Is the underlying pattern of all dynamical physical processes in the universe actually chaotic? [closed]
After studying and pursuing research interests in chaos theory since the mid-1980s, I have to question whether standard physics (including all physical theories we currently use at all scales of size ...
3
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3answers
205 views
Can space expand with unlimited speed?
At the beginning, right after the Big Bang, the universe was the size of a coin. One millionth of a second after the universe was the size of the Solar System (acording to ...
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2answers
73 views
If everything in existence were increasing in size at some rate, would we be able to detect it?
Would our eyes observe any changes?
What about electronic measurement devices?
6
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4answers
922 views
Shape of the universe?
What is the exact shape of the universe? I know of the balloon analogy, and the bread with raisins in it. These clarify some points, like how the universe can have no centre, and how it can expand ...
4
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2answers
103 views
Are all points in the universe connected?
Is it true that every point in the universe is connected or could be so theoretically? If so how is this mediated?
Is it through the quantum nature of the fabric of space or is it through the ...
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3answers
491 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?
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5answers
515 views
Does the amount of gravitational potential energy in the universe increase as it expands?
It seems to me that extra gravitational potential energy is created as the universe expands and the distance between massive objects such as galaxy clusters increases; this implies that energy is not ...
7
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4answers
1k views
Did time exist before the creation of matter in the universe?
Does time stretch all the way back for infinity or was there a point when time appears to start in the universe?
I remember reading long ago somewhere that according to one theory time began shortly ...
0
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0answers
39 views
Has Time in the Universe been found to be Discrete or Continuous? [duplicate]
I have a question, has the Universe been found to come in Discrete Quantum, like Quantum Physics or is it Continuous in Nature?
I was wondering if time was like a Continuum, like the fluid in a soft ...
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0answers
69 views
Do we expect that the universe is simply-connected? [duplicate]
I heard recently that the universe is expected to be essentially flat. If this is true, I believe this means (by the 3d Poincare conjecture) that the universe cannot be simply-connected, since the ...
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1answer
49 views
Would the universe get consumed by blackholes because of entropy?
Since the total entropy of the universe is increasing because of spontaneous processes, black holes form because of entropy (correct me if I'm wrong), and the universe is always expanding, would the ...
0
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1answer
47 views
Could the outer structure of the Universe be made from Antimatter?
Cern recently stated that antimatter may be repelled by matter, much like the opposite effect of Gravity. So is it possible that antimatter is actually repelled to the edges of the Universe to create ...
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2answers
123 views
A question to the theory of multiverse
Guys I couldn't catch a point of multiverse theory..
Theory: If space-time goes on forever, then it must start repeating at some point, because there are a finite number of ways particles can be ...
0
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3answers
88 views
Acceleration in the rate of expanansion of the universe due to weakening gravity?
Could the acceleration in the rate of expansion of the universe be due to the weakening of gravitational forces, as the distance between objects continues to increase?
0
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0answers
25 views
If we find a way to simulate a universe, are we likely to be living in a simulation? [closed]
If we eventually find a way to use quantum computers to simulate the creation of a consistent universe, does that prove that we are extremely likely to be living in a simulation?
0
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1answer
51 views
Is dark matter expanding the universe, and creating the structures within it?
If dark matter repelled other dark matter, as well as regular matter(atomic or celestial), and regular matter were repelled by other regular matter "less" than by the dark matter, would not this ...
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3answers
118 views
Cosmological redshift interpretation
Can the cosmological redshift be interpreted as atomic frequencies increasing by the scale factor as the Universe expands?
This explanation seems closer to the truth than the popular idea that a ...
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2answers
123 views
Is this a great flaw in big bang theory? [duplicate]
Einstein said that, Time & Space cannot exists without one another. Big bang says, time didn't exist before the big bang. So the Primordial ball referred in the Big Bang theory didn't had any ...
0
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1answer
97 views
What is the curvature of an empty universe?
My calculations tell me an empty universe has hyperbolic curvature. Is this correct? If it is, can anyone help me understand why this is intuitively?
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3answers
115 views
What is meant when it is said that the universe is homogeneous and isotropic?
It is sometimes said that the universe is homogeneous and isotropic. What is meant by each of these descriptions? Are they mutually exclusive, or does one require the other? And what implications rise ...
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1answer
71 views
How fast did hydrogen atoms travel when they were first formed in the early universe?
I can't seem to find any data on this, is it a known value?
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2answers
133 views
If the universe is 3D, how is space-time like a “fabric”? [duplicate]
I have been taught that space-time should be viewed as a fabric and that objects with a large gravitational influence indent that fabric. My question is, if the singularity of a black-hole punctures ...
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2answers
76 views
can we have a parallel earth made of dark matter?
In the sense that the two planets move together and has intelligent beings with their own forces and particles, but they just do not interact with (are invisible to) us?
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3answers
127 views
Universe to energy
Would it violate any known laws of physics to construct a universe containing no mass, only energy?
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2answers
176 views
What's the avarage temperature of the Universe?
I'm sorry if this was asked before but with all the stars and dark matter and all the other stuff, curently in the Universe, what's the avarage temperature of the Universe? Is it like extremely high ...
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3answers
446 views
How can a quasar be 29 billion light-years away from Earth if Big Bang happened only 13.8 billion years ago?
I was reading through the Wikipedia article on Quasars and came across the fact that the most distant Quasar is 29 Billion Light years. This is what the article exactly says
The highest redshift ...
3
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2answers
502 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 ...
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0answers
60 views
Total positive charge in the Universe
In their last homework, some of my students miscalculated a charge to be $10^{20}$ C over a squared meter and I was wondering if there was as much positive charges in the entire Universe. It would do ...
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3answers
186 views
How do we know for certain that space is expanding?
How do we know for certain that space is expanding?
Let's say that in the year 1950, we observe that galaxy 1 is 5 billion light years away from us and galaxy 2 is 10 billion light years away from ...
6
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4answers
489 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 ...
2
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1answer
137 views
What determines the end of space (universe)?
What determines the end of our universe?
Is it defined by the farthest out physical object or is it defined by the farthest out form of energy like light?
3
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3answers
131 views
Looking out into the universe means looking back in time - how does that work?
This is a question that has been gnawing on me for many years now. Back a long time ago, as I recall in reference to a scene in a popular science show on TV, I was asked the following.
The claim is ...
