So wheres the speed of light. Assuming that youre having a microwave at home you could measure the speed of light. The speed of light in a vacuum stands at exactly 299792458 metres per secondThe reason today we can put an exact figure on it is because the speed of light in a vacuum is a universal.
When the Earth is farther away it takes light from Io longer to get to Earth resulting in a longer apparent orbital period of Io.
So at least at first glance it would seem that Einsteins axiom of a universal speed of light leads to paradoxical nonsense. Any electromagnetic radiation radio waves infrared radiation ultraviolet radiation light radiation propagates in vacuum at the speed of light c. Now since the speed of light is equal to the wavelength times the frequency we can figure out the speed of light. Exton and Shah measured that distance as 012 meters or 012 meters per cycle.