Force and Motion: Facts. Motion makes the world go 'round. Motion makes the moon go 'round too. In fact, motion makes lots of things go. When we think of motion we often think of cars, bicycles, kids running, basketballs bouncing and airplanes flying.
What are stars made of? Basically, stars are big exploding balls of gas, mostly hydrogen and helium. Our nearest star, the Sun, is so hot that the huge amount of hydrogen is undergoing a constant star-wide nuclear reaction, like in a hydrogen bomb. Even though it is constantly exploding in a nuclear reaction, the Sun and other stars are so large and have so much matter in them that it will take billions of years for the explosion to use all the fuel in the star.
Planets are made of whatever happens to be floating around in space. Typically, it all starts with clouds or stellar disks of gas and dust, which begin to condense due to gravity in any places that are slightly more dense than others. The more the gas and dust pull together, the greater the mass of the protoplanet, and the stronger its gravity to pull even more gas and dust into it. Exactly which elements the dust consists of will depend on nearby stars. In an area of young stars with no history of supernovae , elements heavier than Iron will be very scarce, while in an area where supernovae have occurred, the full range of naturally occurring heavy elements might be found.