If there were no gravity, planets wouldn't stay in space. They would simply drift off in straight lines in whatever direction they were moving at the moment gravity ceased to exist.
Here's why:
* Gravity is the force that holds everything together. It's what keeps planets orbiting stars, moons orbiting planets, and even us on the ground.
* Without gravity, there'd be no force pulling planets towards a star. They wouldn't be bound in orbits, they'd just float freely.
Think of it this way:
Imagine you're spinning a ball on a string. The string represents gravity. If you let go of the string (remove gravity), the ball will fly off in a straight line.
The universe as we know it wouldn't exist without gravity. Stars wouldn't form, planets wouldn't exist, and even atoms wouldn't hold together!
