Just use mirrors and make it go in a circle a b c d e f
Or get the signal back with electricity.
So yeah we do know.
This doesn’t even answer OPs question and is just a shower thought IMO.
Comment on What do people claim they know of but really don't?
Steve@communick.news 13 hours ago
The speed of light from point A to B.
Seriously.
For complicated reasons every measurement of the speed of light is bouncing off something back to the source. It might be very different each way, and we can only average them.
Valmond@lemmy.dbzer0.com 11 hours ago
jdr@lemmy.ml 11 hours ago
What are these complicated reasons?
Steve@communick.news 11 hours ago
Veritasium video about it.
bizarroland@lemmy.world 12 hours ago
At the same time, though, every time the speed of light has been measured, it has always been the exact same, unless something was being done to it to cause it to slow down.
So we are highly confident that the speed of light in vacuum is a exactly equal to 299,792,458 meters a second.
Steve@communick.news 12 hours ago
Right. But it could be faster in one direction than the other, and we don’t have a way of knowing.
bizarroland@lemmy.world 11 hours ago
Light doesn’t really have a direction.
It only appears to have a direction in time.
From the point of view of the photon, it exists as an atomic emission, immediately hits its target, and is reabsorbed.
So there is no back for it to come from.
Steve@communick.news 11 hours ago
From the perspective of light, time itself doesn’t exist, so speed doesn’t exist.