Given the sun's mass (Ms = 2 x 10^30 kg) then earth sun distnace (1.5 x 10^11 m) Newtons Constant G = 6.7 x 10^-11 Nm^2 kg^-2 use a GEOCENTRIC frame to explain the earth's orbit (approcximate as a circle) This was a question on my test and at first sight i was shocked. But geocentric... if geocentric then the earth would be at the centre and the sun would revolve around the sun. Would the sun have its own circular orbit around orbit as well? AAANy help would be greatly appreciated!!