When a star is born the surrounding material that is left is called planetary protomaterial. This material is made up of layers of gases, ice crystals and other solid matter. The larger pieces start pulling in the smaller ones by using gravitational pulls and time. Over time, these larger pieces start to clear out a path around the star that they orbit. Following current thinking the reason that the largest of the planets are on the outer portion of the solar system is that is where th

Stable orbits are final achieved when the planets gain one of three different distance ratios from one another. The first one, a 2:1 ratio, is most commonly found between the planets that are the farthest from the system's star. As the planets distance from the system star decreases so does the stable orbit ratio. For the planets that are in the middle of the orbital disk, a ratio of 3:2 is needed to maintain a stable orbit. The planets closest to the system star require a 5:3 ratio to maintain an orbit that will survive. Once a stable orbital system is achieved, the solar system becomes a balanced system where each planet helps to keep its neighbors in their own orbits.

Any outside influence (i.e. stray comets or asteroids) can change a once stable set of orbits into a cascading change that will change the orbits of all the planets in a solar system. In 1994, this solar system got to see an example of outside influence in action when the Shoemaker-Levy 9 comet came plowing in. If the Shoemaker-Levy 9 comet had hit a planet that did not have the mass to absorb the repeated impacts it would have changed the target planet's orbit thereby changing the orbit of every other planet in t

Some common words found in the essay are:
Goldreich Tremaine, , solar system, American Sept, planet solar, planet solar system, larger pieces start, planets clean, shoemaker-levy 9 comet, 9 comet, growing planet, change orbits, system star, shoemaker-levy 9, orbits planets, orbital disk,
Approximate Word count = 813
Approximate Pages = 3 (250 words per page double spaced)