system
Given the following post, respond as if you're commenting on Reddit:
human
How far from earth do you have to be when you change from perpetual free fall going around the earth to being in zero gravity?

If such a point even exists.
gpt
It's not exactly about distance - it's about speed, or kinetic energy. But beyond some distance, the speed you need becomes very small.

If you are above escape velocity, then the Earth's gravity will never be enough to pull you back down. Even though the gravity is constantly pulling you, it gets weaker as you continue to go further away, and it never adds up to enough to pull you back.

As you go further away, the escape velocity you need to escape Earth's gravity becomes smaller. If you are 4x more distant from the centre of the Earth, you need half as much speed. On the Earth's surface, you need to go quite fast - about 11 km/s - to escape Earth's gravity, even if you don't count drag from the atmosphere. From the Moon's orbit, you only need to go 1400 m/s, or about 5000 km/h. Once you get to Jupiter or Saturn, this gets down to 100 km/h, which is much lower than the speeds that planets and moons are moving at. And once you're a light year away, the escape velocity is about 1 km/h.

This is quite a big distance. If there were no other objects in the universe, you would have to get to a significant fraction of a light year away before escape velocity gets to around walking speed. But of course, we live in a universe with other stars and planets, and these tend to move at 10s to 100s of km/s relative to each other. Earth's gravity stops being important mostly because you're closer to something else that is providing far more gravity, or you're moving so fast that Earth's gravity doesn't have time to add up to much.