The first estimation of the speed of light was based on observing . lanterns the moons of Jupiter a rotating octagonal mirror a lightbulb?

The first estimation of the speed of light was based on observing a rotating octagonal mirror. This method was employed by French physicist Hippolyte Fizeau in 1849, who measured the time it took for light to travel to a distant mirror and back. By analyzing the rotation speed of the mirror, he was able to calculate the speed of light with remarkable accuracy.