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Accepted

Why is the photon clock equivalent to all clocks?

Invoke the principle of relativity. An inertial observer carries both a light clock and a mechanical wristwatch, which agree when all are at rest. If they don't agree when the inertial observer is ...
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• 103k
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Why does the 'sticky bead argument' for (gravitational waves carrying energy) work?

I would guess that the argument applies to the case where the frequency of the gravitational wave is low compared to the natural frequency of the stick, or put another way, the rate of change of ...
• 357k
Accepted

Will heat flow by conduction oscillate until thermodynamic equilibrium is reached in a solid object?

You are mistaken. You seem to be assuming that there is some kind of inertia in the process of heat transfer, as in water sloshing about in a tank. There is no such inertia here, so there is no ...
• 27.4k

Pressure in giant ball of water floating in space

Assuming this giant ball of water can hold itself together due to cohesion, wouldn't you still feel the pressure from...well, simply the water molecules themselves, moving randomly in all directions? ...
• 15.3k

Ground → ship Wi-Fi bandwidth in my fast moving spaceship

There are two effects due to relativity. The motion of the spaceship around the satellite results in a time dilation that can be calculated using special relativity. If the satellite has ...
• 24.8k
Accepted

What time does the particle reach the screen in this thought experiment?

I just finished a thesis on this subject and I'm happy to share. None of the linked papers are my own. The time of arrival in quantum mechanics is actually a subject of ongoing research. It is ...

Can we theoretically guide cold air from high altitude down to the needy cities as free AC?

Believe it or not, the air at the bottom of the tube would be just as hot at the air at the same height outside the tube. In air that's well mixed, the temperature decreases as you go up at a rate ...
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Are there any yet unresolved SR paradoxes?

No, there are no unresolved paradoxes in special relativity. It is more than a century old and has been thoroughly studied. At this point in history any claim that there is a logical flaw in SR should ...
• 9,276
Accepted

Ambiguity in applying Newton's shell theorem in an infinite homogeneous universe

Updated 07.11 We can chose the model to discuss the problem and so let us chose: Model: Newtonian mechanics/Newtonian gravity, with the Universe filled with uniformly dense matter, interacting only ...
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Why is the photon clock equivalent to all clocks?

Based on my current understanding of the topic the light clock is not a proof of time dilation but simply a clue, pointing at it. You are absolutely right in stating that the light clock is not a ...
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Are quantum fluctuations observable?

I believe there are cases where they are observable. Especially through their effects. In cosmology, for example, quantum fluctuations in the early inflationary epoch are considered to have seeded the ...
Accepted

How to read voice clips off a glass plate?

We will assume that the "molten glass" never actually became a liquid, as it would have fallen from the window and created a pool on the ground. The best we can hope for is that it became ...
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Maxwell's Demon: Why does the entropy of the overall system decrease?

There are different kinds of entropy here. The thermal entropy due to the molecules moving faster or slower is a red herring and actually isn't important for understanding Maxwell's demon at all. ...
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Why is the photon clock equivalent to all clocks?

Why is the photon clock equivalent to all clocks? Stipulate that, in some inertial reference frame, there is a photon clock and some mechanical clock that are co-located and at rest in this frame. ...
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Is motion un-observable? and if so how can we know it exists?

You must be using the word motion in a very specific sense, because in the more general sense of the word motion is clearly observable. Motion is a change of position over time, and we can clearly ...
• 26.4k