Satellite gravimetry

Ok kiddo, imagine a huge ball floating in the sky. This ball is so massive that its own gravity pulls everything towards it. And when things get pulled towards the ball, they stick to its surface. This ball is Earth.

Now, imagine we want to know how strong Earth's gravity is at different spots on its surface. To do that, we can use a special tool that measures how fast things are moving when they fall towards Earth. The faster they fall, the stronger Earth's gravity is at that spot.

But what if we want to know how strong Earth's gravity is at different spots in the ocean? That's where satellite gravimetry comes in.

We can send a satellite up into space with a special tool on it that measures how fast the satellite is moving towards or away from Earth. This speed is affected by Earth's gravity. So, by measuring the speed of the satellite, we can figure out how strong Earth's gravity is at different spots in the ocean.

But wait, there's more! Earth's gravity isn't the same at every point on its surface. There are areas where it's stronger or weaker. These differences can be caused by things like mountains, ocean currents, and even changes in the mass of the planet due to things like ice melting.

By measuring the changes in Earth's gravity over time, satellite gravimetry can help us understand how our planet is changing and what might be causing those changes. Pretty cool, huh?