Third+Version-+First+Draft

__The orbit of the planets in Solar system: Sun's action Vs. Interactions inside the system.__

The Solar System is a set of planets and asteroids moving around the Sun, a big red star composed mostly __by__ **of** hydrogen and helium, representing more than 98% of the mass of the complete system. Such __as__ **a ??** celestial body, as you might be thinking, is very related to the gravity inside the system, to the forces that attract bodies between each __othr,__ and, consequently, to the movement of those bodies.

Planets move around the Sun describing particular curve lines called //ellipsis,// the same curves you obtained whenever you cut a cone with any plane that is not parallel to the basis of the cone, mathematically described as, given two fixed points, the set of other which distances to those two always sum a constant. Basically, an ellipse is kind of a circumpherence with two centers, named focus, so i__s it longer one axis than the perpendicular one.__ **confusing**

There are two theories __explainig__ why planets move that way. The __firs__ one proposes it is due to the relationship between all the bodies in the system, planets, asteroids __an__ Sun, arguing that, as every planet as its own gravity force, all the planet **s** attract into each other, so the movement of any of them is caused by a lot of different forces acting simultaneously on it. The second theory asserts the movement of each bod__ie__ is due to the interaction between itself and the Sun, and dismiss all the other possible interactions inside the System

This second one seems to be closer from true. Those people who __deffend__ this second theory are usually based on the fact th **at the** Sun is bigger and "heavier" than the rest of the system joined __togheter__, so, it is reasonable to think this huge hot mass must __aplly__ a gravitatory force on each planet that is ten times stronger __to__ **than** any other __over it__. After remembering planets move around the Sun, it also turns out that, after drawing the orbit of each planet, the Sun is on one of the focus of each ellipse, so the distance to the Sun, (and to the other focus, that depend on each planet) condition **s** the orbit.

__So__, **use "therefore" to start a sentence...** the ellipsis that planets describe through their movement must have one focus on the Sun, the biggest and more important body **of ??** the whole system, which appl__y__ **ies** the most important gravitatory force on each one of them. The orbits of the planets are determined by its interaction with the Sun.

**Wow. It looks great. You need to conclude with your point of view... Which one do you support and why?**