Gravity is weaker on equator. What I know, this effect is due to combination of two factors: 1. Earth is rotating with surface speed 450 m/s on equator and this is causing centripetal force which is decreasing gravity. 2. Earth is flattered on poles, so that means that there is longer distance between surface and center of Earth on equator. So my question is if there were a satellite which would be orbiting Earth in perfect circle (with the same distance from Earth center) from pole to pole and if this satellite would be measuring gravity of Earth, would it measure the same gravity on whole orbit? I know, that Earth is not perfect object and there are small differences in gravity depeding on example of mountains and oceans, but apart from these small influences, would be gravity the same? Or does this equator centripetal force have some effect on orbiting satellites? Was there any real life experiment, which measured something similar? For example I know that Gravity probe B was orbiting from pole to pole, but what I know it has somehow automatically compensated measured gravity depending on longitude.