This video reminds me of the Veritasium video on the impossibility of measuring light in one direction: https://www.youtube.com/watch?v=pTn6Ewhb27k https://www.

This video reminds me of the Veritasium video on the impossibility of measuring light in one direction: https://www.youtube.com/watch?v=pTn6Ewhb27k https://www.youtube.com/watch?v=pTn6Ewhb27k We don't KNOW for a fact that light travels the same speed in both directions when we measure it, but it seems likely.