What is in space?

Is space empty? The universe contains every substance and every kind of energy we know, and yet huge portions of it are completely empty. What is around you while you are in space depends on where you are in space. If you are on the surface of a planet, your experience is very different than if you are in a nebula, a meteoroid field or next to a star.

Ask any question below to learn about everything that is in space.

What is in space besides planets and stars?
Is there gravity in space?
Is there sound in space?
What is energy?
How do objects in space travel?

How do we know what's in space?