←back to thread

A laser pointer at 2B FPS [video]

(www.youtube.com)
615 points thunderbong | 1 comments | 19 Oct 25 06:42 UTC | HN request time: 0.207s | source
Show context
MostlyStable ◴[20 Oct 25 22:18 UTC] No.45650133[source]▶
As I understand it, this is sort of simulating what it would be like to capture this, by recreating the laser pulse and capturing different phases of it each time, then assembling them; so what is represented in the final composite is not a single pulse of the laser beam.

Would an upgraded version of this that was actually capable of capturing the progress of a single laser pulse through the smoke be a way of getting around the one-way speed of light limitation [0]? It seems like if you could measure the pulse's propagation in one direction, and the other (as measured by when it scatters of the smoke at various positions in both directions), this seems like it would get around it?

But it's been a while since I read an explanation for why we have the one-way limitation in the first place, so I could be forgetting something.

[0] https://en.wikipedia.org/wiki/One-way_speed_of_light

replies(5): >>45650372 #>>45650820 #>>45650856 #>>45650907 #>>45651129 #
1. evanb ◴[20 Oct 25 23:44 UTC] No.45650820[source]▶
No, you cannot escape the conclusion of the limitations on measuring the one-way speed of light.

While the video doesn't touch on this explicitly, the discussion of the different path lengths around 25:00 in is about the trigonometric effect of the different distances of the beam from the camera. Needing to worry about that is the same grappling with the limitation on the one-way speed.