* Theoretically, gravity never truly reaches zero. According to Newton's law of universal gravitation, every particle in the universe exerts a gravitational force on every other particle. This force diminishes with distance, but it never completely disappears.

* Practically, gravity becomes negligible at extremely large distances. While technically non-zero, the gravitational force between two objects becomes incredibly weak over vast distances. For practical purposes, it's considered effectively zero.

Think about it this way:

* Imagine throwing a ball: You can feel the Earth's gravity pulling the ball back down.

* Now imagine throwing the ball into space: The ball would still be affected by Earth's gravity, but the force would be much weaker. As the ball travels further, the effect of Earth's gravity would diminish even more.

* At some point, the ball would be so far away from Earth that the gravitational pull from other celestial bodies would be stronger. This is why a spacecraft orbiting the Sun isn't pulled back down to Earth.

So, the answer is:

* Theoretically: No, gravity never reaches zero.

* Practically: Yes, gravity becomes negligible at extremely large distances, essentially reaching zero for all practical purposes.

It's important to note that these are simplified explanations. The actual behavior of gravity is much more complex, especially when considering Einstein's theory of general relativity. But for everyday understanding, the above explanation is sufficient.