THE SOLAR SYSTEM

                 WHAT IS THE SOLAR SYSTEM?

It is our Sun and everything that travels around it. Our solar system is elliptical in shape. That means it is shaped like an egg. The Sun is in the center of the solar system. Our solar system is always in motion. Eight known planets and their moons, along with comets, asteroids, and other space objects orbit the Sun. The Sun is the biggest object in our solar system. It contains more than 99% of the solar system's mass. Astronomers think the solar system is more than 4 billion years old.

Astronomers are now finding new objects far, far from the Sun which they call dwarf planets. Pluto, which was once called a planet, is now called a dwarf planet.

METEORITE:
A piece of stone or metal from space that falls to Earth's surface.

COMET:
A big ball of dirty ice and snow in outer space.

ASTEROID:
A rocky space object that can be a few feet wide to several hundred miles wide. Most asteroids in our solar system orbit in a belt between Mars and Jupiter.

SATELLITE:
An object that moves around a larger object. There are natural satellites such as moons and there are man-made satellites such as the Hubble Space Telescope.

PLANET:

A planet is a large space object which revolves around a star. It also reflects that star's light. Eight planets have been discovered in our solar system. Mercury, Venus, Earth, and Mars are the planets closest to the Sun. They are called the inner planets. The inner planets are made up mostly of rock. The outer planets are Jupiter, Saturn, Uranus, and Neptune. Jupiter, Saturn, Uranus, and Neptune are large balls of gases with rings around them. All eight planets travel around the Sun in a different orbit. In its orbit, there are not many other objects like the planet.

Dwarf planets are objects that are similar to planets except that they orbit the Sun in areas where there are many similar objects.