Measuring the Speed of Light

1. Oct 15, 2005

dekoi

As a result of his observations, Roemer concluded that eclipses of Io by Jupiter were delayed by 22 min during a 6 month period as the Earth moved from the point in its orbit where it is closest to Jupiter to the diametrically opposite point where is is farthest from Jupiter. Using 1.50 x 10^8 as the average radius of the Earth's orbit around the Sun, calculate the speed of light from these data.
I have absolutely no idea how to start this. Please give me some suggestions.
Thank you.

2. Oct 15, 2005

sqrt(-1)

First ask yourself how much further the light has to travel when the earth is furthest away from Jupiter compared to when it was closest to Jupiter. (Note that your value for the average radius of the earth's orbit around the sun is given in kilometres)