The speed of light being isotropic has been demonstrated already and I believe I know what they mean when they say “both ways” : since all demonstrations of the speed of light are based on “round way trip” from A to B then from B to A. But, no experiments can measure a one-way trip speed.
An isotropic medium is one such that the permittivity, ε, and permeability, μ, of the medium are uniform in all directions of the medium, the simplest instance being free space.
… if you read this like i do, they do not care to diferentiate “round trip” and “one way” … and my vocabulary is not good enough to find a word that would fit.
As far as I understand, even if c is different in some circumstances or changes over time it would be hard to measure because everything else is expressed with c
It’s like trying to measure if your fingers have grown longer, but doing it with only those fingers as a measure
I wouldn’t but it has been historically. Unsurprisingly with mirrors but always under the not insignificant influence of the suns gravity. Our most recent measurements I believe use cosmic bodies I believe which is what makes me wonder if our measurement is accurate. https://www.speed-of-light.com/historical_measurements.html
Oh sorry, I was talking about measuring C rather than 2C (since that is the only way we can get C, IIRC, you cannot measure C directly since SOME information must be conveyed when measurement begins AND ends, hence 2C). For C in a gravitational field, I have no idea but I suspect it will have something to do with relativity and time dilation if it has any effect at all.
Good point and black holes are part of make me wonder about that given what it does to light and spacetime. All our measurements of the galaxy and universe is on a speed of light is in our gravity well and even though it drops off so quickly the suns is so huge we have to have quite a distance to get to where its inconsequential is way beyond earth. Knowing there it is the same 1000 au from the sun at high precision would be nice to know. It it showed any difference. Even slightly then it would be massive in our understanding of the universe.
I just want them to prove that C is actually a constant both ways.
C has const, yes. C++ also has this.
🤡
Not sure what are those “both” ways, but yeah isotropic or especially anisotropic speed of light would be nice to know for sure
The speed of light being isotropic has been demonstrated already and I believe I know what they mean when they say “both ways” : since all demonstrations of the speed of light are based on “round way trip” from A to B then from B to A. But, no experiments can measure a one-way trip speed.
Then I was probably incorrect, what would be a correct term for isotropic but depends on direction? Because I also meant one-way speed
Hi lad,
i was not certain so i double checked :
https://en.m.wikipedia.org/wiki/Isotropy
Physics - - Electromagnetics :
… if you read this like i do, they do not care to diferentiate “round trip” and “one way” … and my vocabulary is not good enough to find a word that would fit.
I want to know if the C constant is the same when not under the effects of a gravity well.
Is that under debate?
for me it does as I know of no meaurement done under those conditions.
As far as I understand, even if c is different in some circumstances or changes over time it would be hard to measure because everything else is expressed with c
It’s like trying to measure if your fingers have grown longer, but doing it with only those fingers as a measure
so you believe c was never directly measured?
Well, how would you measure C directly? You can only always get 2C.
I wouldn’t but it has been historically. Unsurprisingly with mirrors but always under the not insignificant influence of the suns gravity. Our most recent measurements I believe use cosmic bodies I believe which is what makes me wonder if our measurement is accurate. https://www.speed-of-light.com/historical_measurements.html
Oh sorry, I was talking about measuring C rather than 2C (since that is the only way we can get C, IIRC, you cannot measure C directly since SOME information must be conveyed when measurement begins AND ends, hence 2C). For C in a gravitational field, I have no idea but I suspect it will have something to do with relativity and time dilation if it has any effect at all.
Isn’t Earth a gravity well, or nah?
when not under the effect and the big gravity well in teh area is the sun. maybe the voyager craft are far enough out for it to be weak enough.
Even then, we are still in the gravitational field of our galaxys black hole.
Good point and black holes are part of make me wonder about that given what it does to light and spacetime. All our measurements of the galaxy and universe is on a speed of light is in our gravity well and even though it drops off so quickly the suns is so huge we have to have quite a distance to get to where its inconsequential is way beyond earth. Knowing there it is the same 1000 au from the sun at high precision would be nice to know. It it showed any difference. Even slightly then it would be massive in our understanding of the universe.
Yeah, this is a teally intresting thought! The observation should be really somewhere outside of galaxies, or where there is almost no gravitation.