In the gravitational tug-of-war between the earth and sun for the moon, which wins?

Question

In other words, does the moon revolve around the earth or the sun?

Answer 1

Scientifically, here's the answer: Fg= G x g1 x g2 / d²

So...

The constant G times the mass of one body times the mass of the second divided by (the distance between the two squared.) So, which is bigger, the difference of the distance between the sun and the moon and the earth and the moon (squared), or the mass difference between the earth and the sun?

G= 6.67 x 10^11  blah, blah, blah, you can neglect this because it will be in both equations.

Mass of earth = 5.98 x 10^24 kg

Mass of moon = 7.35 x 10^22 kg

Mass of Sun =  2 x 10^30 kg

Average:

distance, Earth to moon = 3.84 x 10^8 m

distance, Sun to moon = 1.5 x 10^11 m

So the pull between the earth and moon would be 3 x 10 ^ 30  times (G)

and the pull between the sun and moon would be 6.5 x 10^30 times (G).

So...

the sun has a stronger gravitational pull on moon than the Earth does. However, the Earths pull and inertia keep it in its orbit.

Answer 2

earth because the moon is closer to the earth thus our gravitation pull is greater on the moon than the suns gravitational pull

Answer 3

Well, neither the sun or earth wins, and the moon rotates around both the sun and earth.

Answer 4

earth just coz we all live on it an the earth kicks ***

Answer 5

The moon revolves around the Earth.

The Earth wins in this struggle because while gravitational force is proportional to mass (and the sun is bigger), it is also proportional to the inverse of distance squared (and the Earth is MUCH closer).

Thus, Earth exerts a much greater gravitational pull on the moon.

Answer 6

Do the calculation.

F = G M m / d^2

The Sun pulls much harder on the Moon than Earth does (which was the first hint that it is special for us to have such a large Moon, so far out).

However, the pair is in orbit around the Sun.  All the other major satellites in the Solar system have a part of their orbit that curves away from the Sun for at least a small portion of their path.

Not the Moon.  If you were to carefully measure its zig-zag path around the Sun, you'd see that it is always curving towards the Sun.

This caused some people to propose that Earth and Moon should be considered a double-planet.  But the modern definition of a double planet requires that the centre of mass for the pair be located outside each body.  In our case, the centre of mass of (Earth + Moon) is still inside Earth.  Therefore we do not fit the definition of double planet.

The pull of the Sun is not sufficient to break the link that causes the Moon to stick around Earth.  In other words, the Sun can never bring the Moon to its escape velocity relative to Earth.

The Moon is moving away from us (4 cm per year) but that is due to its tidal effect on Earth, not to the pull from the Sun.

The Sun does have an effect on the shape of the Moon's orbit.  It does not change its mean distance, but it does change its shape, making it sometimes a (tiny) bit more circular and sometimes a (tiny) bit more squished.

Answer 7

The earth, or else we would only see the moon once a year.

Answer 8

The moon revolves in it's 28-day orbit round the Earth, which in turn revolves in it's 365-day orbit round the Sun.

As it happens, the distance from the Earth to the Moon is gradually increasing by a very small amount ( a matter of centimetres ) every year. This means that one day, many millions of years in the future, the Moon will part company with the Earth and either spiral into the Sun, where the matter of the Moon will be converted to energy, or wander off into the vastness of space. By that time Earth will be a very different planet and humans and their descendants will probably be long gone.

In the first of these possibilities, to answer your question, you could indeed say that the Sun had in fact won.