<p>I'm confused about this Physics 2 HW problem... I wanted to know if anyone knows how to do it... it's more conceptual than calculations I think.</p>
<p>The text of the problem is:
One method for measuring the speed of light, based on observations by Roemer in 1676, consisted of observing the apparent times of revolution of one of the moons of Jupiter. The true period of revolution is 42.5 h.
a) Taking into account the finite speed of light, how would you expect the apparent time for one revolution to change as Earth moves in its orbit from point x to point y in the figure?</p>
<p>b) What observations would be needed to compute the speed of light? Neglect the motion of Jupiter in its orbit. The figure is not drawn to scale.</p>
<p>"Jupiter is moving much more slowly than the earth, so we can neglect its motion. When the earth is at point A, nearest to Jupiter, the distance between the two is changing negligibly. The period of Io's eclipses is measured, providing the time between the beginnings of successive elipses. Based on this number the number of oscialations during 6 months is calculated, and when at point c (across diam of earths orbit, b is N, A is E and C is W), the eclipse is 16.6min later that predicted. This is the time it takes light to travel the diameters of earths orbit."
Tipler, For Scientists and Engineers fifth edition.
And you basically consider the distance between the earth and jupiter constant. </p>
<p>In summary,
So basically a moon moves around Jupiter, which is considered in this case to be stationary because its period is so much longer. At point B you get a number of elipses, and predict to get the number at point C. But at point C, the eclipse is later than expected because now the light has to travel the diameter of earth from point A to point C, point A is collinear with Jupiter.</p>
