Questions tagged [one-way-speed-of-light]
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Lorentz ether theory (LET) vs special relativity
According to wiki LET page
“[Mansouri–Sexl] implies that a one-way speed of light experiment could in principle distinguish between LET and SR… In the absence of any way to experimentally distinguish ...
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One-way speed of light and the luminiferous aether
The "luminiferous aether" hypothesis is famously falsified by the Michelson-Morley experiment. It is explained that if there is an aether and we move through it, then there will be an "...
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Speed of Light Which Varies With Direction in 1+1 Dimensional Spacetime
Suppose there are two frames $(t,x),(t',x')$ in $1+1$ dimensional spacetime, with coinciding origins at $t=t'=0$. Furthermore, suppose that unprimed frame observes the prime frame moving at velocity $...
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Did Einstein say the one-way speed-of-light is "not a fact of nature"? [closed]
If so is there a published paper where he said as much?
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Derivation of "Euclidean Lorentz transforms" without the one-way speed-of-light constancy postulate but with the relativity principle [closed]
Here is the derivation of Euclidean "Lorentz transformations" by Gemini 1.5 Pro from the basic postulates but without the one-way speed light constancy postulate. Do you find any faults in ...
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Why can't one-way speed of light be derived with simple wave mechanics? [duplicate]
If we understand light as having a frequency and wavelength, why not just multiply them to get the speed, this doesn't require mirrors or synchronised clocks. I'm 100% sure this doesn't work, but I ...
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One-way speed of light through long tube [duplicate]
Let's assume we have a long, narrow tube perpendicular to a wall that emits light (similar to the ones doctors use to look at radiology films). On the other side of the tube there is a sensor (mounted ...
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Could we measure the one-way speed of light with two connected rotating apertures? [duplicate]
Can we measure the one-way speed of light by passing light through angularly shifted apertures in two disks solidly connected and spinning at a known angular velocity?
Here is the apparatus I would ...
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How do you calculate kinetic energy in a convention where the one-way speed of light is anisotropic?
The question about measuring the one-way speed of light has been debated in several posts in this forum, and are treated in detail on this wiki page.
In relation to this debate, I wonder how you would ...
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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, ...
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Measuring one-way speed of light [duplicate]
Veritasium's video explains why we can't measure the one-way speed of light: https://youtu.be/pTn6Ewhb27k?si=60Q0AffVdt09lJSb
However, I still don't completely get why this is the case.
Let's say that ...
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What's wrong with this One-Way Speed of Light experiment? [duplicate]
I can't tell what's wrong with it.
Imagine the wheels of a car, jack the car, put a sensor on one wheel, a laser on another, start rotating, with enough speed the sensor will start to detect the laser ...
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Clarification about the one-way vs two-way speed of light
I've just watched Why No One Has Measured The Speed Of Light by Veritasium, but I haven't really understood why this debate exists.
The reason for my misunderstanding, I believe, is that the whole ...
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Is it possible to measure the one way speed of light with redshift [duplicate]
By this I mean say you had and entire galaxy to work with, and you could measure the exact wavelengths of the waves you send out and record it. You would shoot this light beam across the galaxy and ...
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Why cant one-way speed of light be measured using a timer start that is electronically connected at midpoint? [duplicate]
Why can't one-way speed of light be measured using a timer start that is electronically connected at midpoint?
I'm sure I'm missing something, but why can't an experiment be built with two timers that ...
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Are the non-standard one-way speed of light conventions just transformations of coordinates?
There are a lot of posts and confusion regarding the fact that different standards of simultaneity result in different one-way speeds of light (OWSOL) (that may be non-isotropic). Of course, the ...
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Lorentzian Relativity
The same old questions and scenarios abound on this site about trains, ladders, twins, rockets, simultaneity, and so on.
It was acknowledged by Einstein that Lorentz's later rehashed aether-based ...
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Why are 2 clocks needed to measure the 1-way speed of light? [duplicate]
Obviously with questions about the 1-way speed of light, I have an experiment in mind.
Say you have 2 wheels connected with an axle and you have slots around the edge of each wheel (the slots are ...
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What is wrong with these ways of measuring one-way speed of light? [duplicate]
I thought of 2 ways of measuring one-way speed of light. Can somebody explain why these won't work please?
Create a machine that emits a pulse of light and a sound from far away. Have a clock ready ...
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Calculating the one-direction speed of light [duplicate]
According to Derek Muller from Veritasium, measuring the one-direction speed of light requires synchronised clocks, and that's a problem because moving one of the clocks will slow down its time. In ...
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Time differential between two signals sent at two different near-relativistic speeds
There is something I don't quite get about relativistic velocities, which I am hoping to clarify with this question.
Suppose you have an emitter and receiver both located somewhere far away from one ...
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Can this experiment successfully be used to find out one-way speed of light? [duplicate]
As with almost every question on this topic, this question is also inspired by the Vertiasium video Why No One Has Measured The Speed Of Light.
This experiment tries to measure the one way speed of ...
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Upper and Lower Bounds on the One-Way Speed of Light
I know that the one-way speed of light cannot be measured due to clock synchronization. Knowing this, is it possible to place some kinds of maximum or minimum values on the one-way speed of light, and ...
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What is the “conspiratorial anisotropy” if we would see no star redshifts in one direction of the sky? [closed]
Suppose we see no redshift of stars in one direction only (or better, in directions on a small patch around it). And suppose in that direction (on a patch of sky around it) we see a lot more stars ...
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If the speed of light is different in two opposite direction, wouldn't we see a bright and dim sky in opposite directions? [duplicate]
There have been asked a lot of questions about the direction dependence of the speed of light. The conclusion is that the speed of light can be different in two directions and we can't measure the ...
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Velocity of light in different directions [duplicate]
From what I understand, we have not been able to measure unidirectional speed of light. It is said that theoretically it is possible for light to travel at $c/2$ in one direction and infinity speed in ...
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Would paradoxes arise if the one-way speed of light weren't $c$?
Introduction
Let me start by saying that this is not a question about how to measure the one-way speed of light (OWSOL). It's about the physical implications of the idea that this speed is merely ...
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If I had a car which could go with a speed of light, could I drive it at night? [duplicate]
Just theoretically, when I turn on the lights in my super fast speed of light car, would I see the road if the light can't go faster than my car?
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One-way speed of light confirmation, not measurement [duplicate]
So there's quite a few posts on here about the now infamous YT video about how the speed of light can only be measured as a round trip. I think I understand the issues with the proposed experiments I'...
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Does SR intend to postulate the one- or two-way speed of light?
I have read this question:
It follows that the two-way speed of light is invariant (in the context of relativity, "invariant" is understood to mean "invariant with respect to Lorentz ...
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Can you measure the one-way speed of light using gravity?
I recently learned that you can't measure the speed of light one way, only back and forth. I thought you might be able to use gravity to measure the speed one way.
If you have to stations at the same ...
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Is time dilation applicable to different parts of the same object? (Related to figuring out speed of light in one direction) [closed]
I understand that same object is a bit of a vague and ambiguous term, but hear me out. Like many other people here I got an idea too for measuring the one way speed of light, after watching the ...
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Potential one-way speed of light experiment [duplicate]
Exclaimer, I am in the high school physics range, in no way do I claim to know anything, nor expect to be right, this is just an idea I had when thinking about the one way speed of light
so I was ...
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Can we measure the one-way speed of anything at all? [duplicate]
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 ...
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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 ...
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Is this a valid experiment to measure the one-way speed of light?
Consider the following setup. Place a light source at point $A$ and three mirrors at point $B,C,D$ such that the light follows the path $ABCDA$ (refer diagram). Let the distance $AB=CD=2d$ and $BC=CD=...
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Couldnt we "race" light to determine its one-way speed?
From my (basic) understanding the biggest problem of measuring the speed of light is clock synchronization. But I question why this is necessary. To be more specific, what if, instead of measuring ...
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How to measure the one-way speed of light [closed]
I've a idea for measuring. Pretend you have two clocks with connected light detectors, directly next to each other, and let them connect so the time on both is identical. Then you set one up at the ...
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Measuring the one-way speed of light experiment [duplicate]
I know a lot of people already asked about this, but i still can't figure out why it's impossible to measure the one-way speed of light. Sorry if it's a dumb question, but I'd really like understand.
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Speed of atoms being pushed away
It is said that it is impossible to calculate one-way speed of light.
I have doubts in my small theory and I would like someone to correct me because I lack in knowledge in physics, and I'm surely ...
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How to justify the time taken by a photon to travel from Sun to Earth? [duplicate]
The standard high school textbooks mention that light takes 499 seconds on an average to travel from the Sun to the Earth. Here, I have three questions:
In which frame is this duration of 499 seconds ...
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Are photon wavelength and energy indirect measurements of one-way speed of light?
First, measure the wavelength ($\lambda$) of an EM wave with, say, a chocolate bar in a microwave oven.
Then, measure its average photon energy and get the wave frequency ($\nu=\frac{E}{h}$).
Now you ...
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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 ...
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What is the problem with this method to measure one-way speed of light? [closed]
I am having a hard time grasping the idea that one-way speed of light is immeasurable. I have watched several videos (including the Veritasium one), read the Wikipedia article, and read some questions ...
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Could Mars be used to measure the one-way speed of light? [duplicate]
I just watched this Veritasium video, explaining the difficulty of measuring the one-way speed of light. The presenter explains that a round-trip will always average out to $c$ even if the speed in ...
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Would an anisotropic speed of light possibly allow light to escape a black hole?
It has been proposed that light coming toward the earth is near infinite but that light outgoing is near 1/2 c. I know we cannot directly measure the one-way speed of light, but if anisotropy were ...
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Can Einstein's action at a distance be action into the past?
This youtube video is about how it is not measurable or of any consequence what the one way speed of light is, only that a two way trip has an average speed of $c$. An example is moving ...
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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 ...
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What is actually measured by means of a diffraction grating?
According to elementary optics it would appear that a diffraction grating measures the wavelength of the incident light.
But if that were the case, it would be possible to measure independently both ...
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Is the one-way speed of light in vacuum different depending on direction?
This doesn't seem intuitive (like much of relativity) so I'll explain my reasoning below and hopefully someone can point out where I'm going wrong.
Imagine we're a stationary observer watching a ...
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