How does the moon control the tides with gravity?


How does the moon control the tides with gravity?

In: Physics

put simply, its the largest non earth object which is close enough that its gravitational pull is not ignorable, apart from the sun. the earth tugs on the moon too, so much so that it orbits us.

everything with mass attracts everything else with mass; large objects like planets attract each other from the center of their being, because its the average location of their cumulative mass.


The moon’s gravity squeezes the oceans causing it to bulge in the side facing the moon and the opposite side. The earth spins through the tides even though it looks like the tides are moving in or out themselves.

Okay… so gravity is a force of attraction between any two objects, and the pull of gravity depends on the distance between those two objects. The closer the objects are, the stronger gravity pulls. So the sun’s gravity pulls harder on Mercury than it does on Earth, and it’s much weaker on Pluto and Neptune.

Now, normally when you drop an object like a bowling ball, the size of the bowling ball is relatively small compared to the size of the distance between the bowling ball and the center of the Earth (where the ball is being pulled). So, the Earth is pulling a little bit harder on the bottom of the bowling ball compared to the top, but not enough to ever notice.

The Earth isn’t quite so small. When the moon pulls on the Earth, there is a close side and a far side. The pull of the moon’s gravity is stronger on the close side, weaker on the far side, and somewhere in the middle in the middle.

This effectively elongates the Earth… stretching it on one side toward the moon. Most of the Earth is rock and doesn’t stretch much, but the oceans are not rock and are pretty free to stretch.

On one side of the Earth, the oceans are being pulled more than the Earth itself, so you get a high tide there. On the opposite side of the Earth, the Earth is getting pulled harder than the oceans, so you get a high tide there also.