THE SOLAR SYSTEM AND OUTER SPACE
SOLAR SYSTEM

Solar System
Photo courtesy of NASA

by Kelly MacDonald and Maggie MacLeod

Consisting of the Sun, a family of 9 planets, 63 moons, millions of asteroids, and billions of stars, and comets, our Solar System is home to light, heat, and life. The planets, asteroids, and comets travel around the Sun, the center of our Solar System. The Solar System has an elliptical or egg shape, and is part of a galaxy known as the Milky Way. The inner Solar System consists of the Sun, Mercury, Venus, Earth and Mars. The planets of the outer Solar System are Jupiter, Saturn, Uranus, Neptune and Pluto. Many astronomers believe the Solar System was formed 4.5 billion years ago with the 'Big Bang', a big explosion which caused the stars, comets, asteroids and planets to take shape.

The Sun is the largest object in the Solar System; it contains more than 99.8% of the total mass of the Solar System. The temperature on the Sun is about 15.6 million degrees Celsius.

The 9 planets are the main part of our Solar System. Each planet has a different feature. For example, Mercury is the closest planet to the Sun, and the eighth largest; Uranus tilts on its side; Venus' orbit is the most circular. The planets, starting farthest from the Sun are Pluto, Neptune, Uranus, Saturn, Jupiter, Mars, Earth, Venus, and Mercury.

Another part of our Solar System that is important to us is the Earth's Moon. It is the only natural satellite of our Earth. It also is the second brightest object in the Solar System, after the Sun. The moon appears to wobble a bit; this happens because of its elliptical or oval-shaped orbit.

Our Solar System also consists of small bodies which include asteroids and comets. There are thousands of known asteroids, and many unknown asteroids as well. Between Mars and Jupiter lies the Asteroid Belt. There, thousands of rocks orbit the Sun. Asteroids are sometimes referred to as minor planets or planetoids. Comets are a mixture of ice, water and frozen gases. Comets have three distinct parts, the nuculeus, coma, and the ion tail. Comets also orbit the Sun.

Bibliography and Additional Sources of Information

Welcome to the Planets. pds.jpl.nasa.gov:80/planets/



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