WHAT YOU NEED: an orange, pencil and paper. The orange should be as round as possible, so the peel represents the surface area of a sphere. STEP 2: Repeat this 3 more times. You should now have 4 ...

Moons are either gravitationally captured if they are within what's called a planet's Hill sphere radius, or they’re formed along with a solar system. Objects exert a gravitational force of ...