Questions tagged [one-way-speed-of-light]
88 questions
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Can One-Way Speed of Light be Instantaneous?
I recently watched this video by Veritasium where he talks about the One Way Speed of Light and talks about the limiting case where in one direction the speed of light is $c/2$ while it's instantaneous in the other. He also says this is perfectly…
FoundABetterName
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Meaning and validity of the mass-energy equivalence valid if we don't know the one-way speed of light?
I recently stumbled upon a video (1) which explained that what is assumed to be the speed of light is actually the two-way speed of light.
As explained in the video, hypothetically the speed of light varies across different directions of spacetime.…
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9 answers
Is there any way to measure the one-way speed of light?
Is there any way (practical or theoretical) to measure the one-way speed of light?
The two methods that come to mind are:
Stellar aberration, and
Using adiabatic clocks: synchronize clocks, then slowly move them apart
I think 2 is not really…
Alan
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Is it possible to prove or disprove the Einstein Synchronization Convention with astronomy?
So, I just saw this Youtube video by Veritasium that discusses how it's impossible to measure the one-way speed of light from a light source to a detector, since it's impossible to synchronize clocks in a fashion that would prevent a directional…
nick012000
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Can we measure the one-way speed of anything at all?
I know the one-way speed of light question has been exhausted, and I'm sorry for the naive question, but I would like to understand one thing. Can we measure the one-way speed of anything at all? If we "truly" can, why can't we synchronize that…
Dee Xen
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One-way speed of light experiment, no clocks or mirrors (with simulation)
As can be seen in the many creative questions here, it is hotly disputed whether you can measure the speed of light in only one direction to the point where a infamous postulate was made that the speed of light might be instantaneous in one…
Shaggi
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Can we use curved spacetime to measure the one-way speed of light?
This is related to Measuring one-way speed of light with gravitational lensing and Measuring the one-way speed of light with a black hole?
The idea is to shine a beam of light from a clock towards a heavy mass, like a black hole, in some manner such…
Whynaut
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How can be proved that one-way speed of light is equal to two-way speed?
Using Special relativity theory, of course. Can Lorentz transformations to "tell" something about it?
"Wikipedia's" article:
http://en.wikipedia.org/wiki/One-way_speed_of_light .
user8817
5
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3 answers
One-Way Speed of Light and the Big Bang
Variations on this question have been asked a few times (e.g. here, here, and a few YouTube videos here and here). The claim seems to be that because we can only measure the round-trip speed of light, this leaves open the door for the one-way speed…
user218912
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The one-way speed of light and a YouTube video
In a Veritasium video, it is claimed that it is impossible to experimentally measure the 'one-way speed' $^1$ of light. The host further stipulates the stronger claim that the laws of physics are unaffected by the division of speed of light between…
Rounak Sarkar
- 777
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Has anyone ever measured the one-way speed of light perpendicular to the Earth at the Earth's surface?
1 - Has anyone ever measured the one way speed of photons traveling perpendicular to the Earth at the Earth's surface?
2 - Given our current understanding of Physics is there any way both the upward and downward speed would not be $c$?
3 - If the…
aepryus
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Measuring the one-way speed of light
Could the following experiment help is to compare the one way and the two way speed of light.
We sent a lightpulse from a clock in A. This lightpulse is reflected in B but also activates a lightpulse in B. Both pulses travel to A. We now know the…
Carlos
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4 answers
Do photons slow down?
If $c$ is the 2-way speed of light and we can't measure the one-way speed, how do we know with absolute certainty that photons don't loose speed after a first bounce off of a reflective surface? If we don't know for sure, can we say with certainty…
A Kam
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Is Stellar Aberration a one-way speed of light measurement?
There is a discussion ongoing about the feasibility to measure the one-way speed of light, ever since a Veritasium video on the subject. There is also a wikipedia page about the subject. But Veritasium does not mention Stellar Aberration, and the…
fishinear
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When has the speed of light been measured, recently?
Yes, it is weird, absurd, but I can't stop thinking that the would-be superluminal
neutrino speed has been computed by an arithmetic operation (space/time) and not by direct comparison with a simultaneous light ray running in "parallel".
So the…
user6090
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