All Questions
Tagged with universe reference-frames
41
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Are the mass, diameter and age of the Universe frame dependent?
Mass of the observable Universe is known to be $1.50×10^{53}$ kg. Age is approximately known to be 13.7 billion years.The observable Universe is a sphere with diameter of roughly $8.8\times10^{26}$ m.
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Is the size/age of the universe dependent on your velocity? [duplicate]
As Photons do not experience time or space, then according to my thought experiment, all photons must occupy some kind of singularity as well as what WE observe from earth.
I was also thinking that ...
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Is there any sort of universal coordinate system?
Is it possible to pinpoint the location of the earth in a universal coordinate system of the universe? Maybe the CMB could be used somehow?
user356390
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Is there anything truly "stationary" in the universe? [closed]
Ok, so I read this question and it got me thinking about something. Is there anything genuinely stationary in our universe? What does it mean to be stationary or devoid of any motion? If there isn't ...
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What percentage of the universe's energy is rotational kinetic energy?
Obviously there is constant exchange between different forms of energy, so presumably only an average could be estimated, assuming it is not an ill-posed question.
Also, even if a fairly precise ...
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Why is the CMB's frame not rotating?
I have read this question:
The existence of a CMB frame asserts that there exists a global frame in which the universe is (approximately) space-translationally and rotationally invariant (though not ...
- 29k
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How do we know if a particle is moving or not? [duplicate]
if there is only one particle in the universe, how do we know if it is moving or not?
We don't have any other object to track the distance between the two, then is it possible to determine the ...
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Is "speed relative to the universe" a well-defined concept? [duplicate]
Prompted by commenting on this question.
I offered the standard "Which frame of reference are you using? Yours? A satellite's? The sun's? The Milky Way's?" observation.
Which prompted me to ...
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Is it possible that the center of the universe is outside our observable universe?
Is it possible that the universe does have a center after all, but we just cannot see it because it already fell beyond the event horizon of our observable universe?
If not, how do we know this for ...
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Vacuum energy density with respect to what reference frame?
Wikipedia quotes the observed vacuum energy density to be around $10^{-9}\frac{J}{m^3}$. Whatever the real energy density is, my question is, with respect to what reference frame is this being quoted?
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Motion and the Universe
In physics class today, I learned that motion is relative, and to determine if an object is moving or not, you need to have a stationary reference point.
Well, that got me thinking:
How can you ...
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If there is no absolute time, how can we say the Big Bang was 13.8 billion years ago? [duplicate]
The Big Bang is supposed to have happened 13.8 billion years ago.
Question: Given that there is no absolute time and different observers do not agree on the amount of time that has elapsed, how can ...
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If universe is expanding then relative to what? [duplicate]
I am very keen about the fact that universe is expanding.If something expands, it expands relative to something else. If the universe is expanding, then it must expand relative to something else. What ...
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Does the Universe itself move to any direction on top of expansion?
So the universe expands right, but does this expansion move to any direction in hyperspace as an expanding cluster of matter somewhere?
It's like if you would explode a bucket of paint under the. ...
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If there was but one object in the universe, can it be accelerating or not accelerating?
If there is only a single (material) object in the universe does it still make sense to speak of it as accelerating or not accelerating?
I believe it might be an equivalent question to ask whether it ...
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