How much stronger would the gravitational force be if the moon was two times bigger than the earth?

Answer 1

When you're dealing with the magnitude of the gravitational force between two objects,

size doesn't matter. What matters is their mass.

Right now, the earth's mass is about 80 times the moon's mass. If the moon suddenly

became twice as massive as the earth ... but stayed at exactly the same distance, which

isn't possible but we'll assume that it happened ... then the force between the earth

and moon would become 160 times as strong as it is now. If you think you've ever seen

some really high ocean tides, you would be awe-struck at what would become of the

tides after that. In fact, the tidal forces might be great enough to cause some major

internal structural heartburn in one or both bodies. Without getting too graphic about it,

let's just say that we probably wouldn't have to think about it much after that.