Gravitational pulls

hiorta

A post from an American site. Any views, please?

If the Earth were to be going around the Sun, then the speed of its satellite would have to adjust due to the differences of the gravitational pull of the Earth.

When the satellite is "behind" the Earth, it would have to "chase" the Earth. When the satellite is "in front" of the Earth, the Earth would "chase" the satellite.

Since the Earth is supposed to be going around the Sun with an alleged speed of about 107,534 km/hr, the speed of the satellite - to account for the change of the gravity pull - would have to drastically change. It doesn't, apparently.

If the Earth does not move, and "the universe" revolves around the Earth, Earth's gravitational pull on its satellite would be the same - regardless of its position on the orbit - which seems to be the case.

dbran

Hi

It is rather the entire Earth-Moon System itself that is going round the sun not just the Earth and moon individually.

Also the Earth and Moon both orbit their common centre of mass and not the centre of the Earth. As the Earth is the more massive body by a large amount, the centre of mass of the Earth-Moon system is actually inside the Earth but offset by 1/3 from the centre of the Earth.

So actually if you were to view the Earth-Moon system from outside the Earth would wobble back and forth as well as rise and fall every month as the moon and the Earth both orbited their common centre of mass.

Hope this helps

dbran

hiorta

Thank you. A little light has been shed in a dark corner of my mind.