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.
Massive stars form in the same way as low mass stars--they just form more quickly because there is more mass to speed-up the process. Whereas the Sun took about 50 million years to contract from a cold gas cloud to a main sequence star, a star with 15 solar masses collapses to the main sequence in 60,000 years.