The Sun and all bodies that orbit it—planets, moons, and various kinds of debris (called asteroids, comets, and meteoroids)—make up the solar system, the formation of which would make quite a dramatic movie. The story began quietly, with lots of small encounters between vast numbers of bit players (tiny gas and dust particles). Most of them quickly plunged into the center of the theater and together they formed the Sun, the star of the show. Plot lines developed as the remaining matter interacted. Things started to heat up as matter came together in progressively more violent collisions and near misses. Particles clumped into pebbles, rocks, and mountain-sized pieces of rubble. Sometimes big chunks of debris smashed each other to bits. Eventually, the heavyweights (in this case, bodies destined to become planets and large moons) managed to wipe out most of the smaller players. The drama also led to the evolution of life, a subplot featuring the third rock from the Sun.

Yes, The Making of the Solar System would be a great film—except that it would be in “slo-mo.” Just to get to the part where the planets are well established in their roles, you would have to watch solar system formation for about a hundred million years. In addition, because astronomers and geologists are continually making new discoveries about our solar system, the script would have to be continually revised and scenes reshot.

In fact, several times over the years, astronomers have decided that some bodies thought to be major actors really just play minor roles after all. Perhaps the most interesting way to view such a movie would be to compare it to films that show the formation of planetary systems around other stars, an area of intense research today.