The force that keeps objects from floating off into space is gravity.

Here's why:

* Gravity is a force of attraction between any two objects with mass. The more massive the objects, the stronger the gravitational force.

* The Earth has a large mass, so it exerts a strong gravitational pull on everything near it. This pull keeps us, the atmosphere, and everything else on the surface from floating off.

* The Sun's gravity keeps the Earth and other planets in orbit around it.

Let me know if you have more questions about gravity!