Various ways to measure the speed of light. Many require few modern implements. How to measure constancy of the speed of light—the original experiment, does not require any complicated or mysterious equipment, only careful design.
The early measurements of the speed of light don’t require “modern implements.” They do require quite sophisticated engineering or measurement. In particular, the astronomical measurements are not easy at all. Playing the”how would I prove X to myself” game brought home to me just how hard science is. Already by the 18th century and certainly by the 19th, professional astronomers were sophisticated enough to do measurements I couldn’t easily match without extensive practice and a real equipment budget.
Suppose you were going to measure the speed of light by astronomy. Stellar aberration seems like the easiest approach, and that’s a shift of 20 arcseconds across a time interval of six months. This is probably within my capacities to measure, but it’s the sort of thing you would have to work at. It would be a year-long or years-long observation program requiring close attention to detail. In particular, if I wanted a measurement of the speed of light accurate to within 10% I would need my measurement to have error bars of about 2 arcseconds. I suspect an amateur who knew what they were doing could manage it, but it’s not something you would just stumble onto as a casual observation.
The early measurements of the speed of light don’t require “modern implements.” They do require quite sophisticated engineering or measurement. In particular, the astronomical measurements are not easy at all. Playing the”how would I prove X to myself” game brought home to me just how hard science is. Already by the 18th century and certainly by the 19th, professional astronomers were sophisticated enough to do measurements I couldn’t easily match without extensive practice and a real equipment budget.
Suppose you were going to measure the speed of light by astronomy. Stellar aberration seems like the easiest approach, and that’s a shift of 20 arcseconds across a time interval of six months. This is probably within my capacities to measure, but it’s the sort of thing you would have to work at. It would be a year-long or years-long observation program requiring close attention to detail. In particular, if I wanted a measurement of the speed of light accurate to within 10% I would need my measurement to have error bars of about 2 arcseconds. I suspect an amateur who knew what they were doing could manage it, but it’s not something you would just stumble onto as a casual observation.