A satellite is an object which orbits another. An orbit is the curved path that an object in space takes around another object.

Many years ago, a mathematician named Johannes Kepler created a set of rules explaining planets' movement in our Solar System.

You have likely heard about the Universe expanding. Or that redshift can tell us about the movements of galaxies. Both are difficult ideas to imagine and understand.

Ever wondered how heavy or light you would feel on another planet in our Solar System?