Unit 9/10 THE SOLAR SYSTEM

I. The Force of Gravity Gravity is a force of attraction between objects. This force depends on the masses of the objects and the distance between them. 1.Increasing the mass of the objects increases the force, while increasing the distance between them decreases the force.

B. Gravity and the Planets- gravity is the force that holds the planets and other objects in the solar system in their orbits. Satellite- any object that orbits another object in space Ex. The earth is a satellite of the sun 2. The closer a planet is to the sun the faster it moves in its orbit

II. Solar System Terrestrial Planets (rocky)- 1. Earth is the densest of the rocky planets B. Gas Giants- the name given to Jupiter, Saturn, Uranus, and Neptune because these planets are mostly made up of compressed gasses

C. Earth is Unique- 1. It is the only planet that has abundant liquid water 2. Only planet with an atmosphere with abundant free oxygen

III. Asteroids, Meteors, and Comets Oh My… Asteroids- sometimes referred to as minor planets, or just rocky objects

B. Meteors- “Shooting Stars”, a natural object that has fallen to the Earth from space. They produce a light visible at night across the sky.

C. Comets- icy objects, most of which originate in a region outside the planets. Comets can be visible for weeks.

Lets Check It Out! Meteors, Comets, and Asteroids Meteorites Strike Earth