system
Given the following post, respond as if you're commenting on Reddit:
human
Why does the Moon's gravity cause tides on earth but the Sun's gravity doesn't?
gpt
The Sun's gravity actually *does* cause tides! They're just weaker than the Moon's tides.

The Sun's gravitational force on the Earth is stronger than the Moon's, but its tides are weaker. This is because tides decrease with distance more quickly than net gravity does.

Tidal forces are caused by the difference in gravity between one side of the planet and the other. Gravity drops off with distance, so one side of the planet gets pulled a bit more than the other. This causes the planet to get stretched a little bit, which is the tidal force.

If you're close to an object, gravity is dropping rapidly, which means that the tidal forces are extra strong. They're strong because the net gravity is strong, but they're extra strong because the gravity is dropping fast with distance. This is what makes tides decrease more rapidly with distance than net gravity, because there are, in a sense, two effects to make it stronger when you're close.

So the Moon ends up dominating our tides, even though we orbit the Sun.