"Suddenly, from behind the rim of the moon, in long, slow-motion moments of immense majesty, there emerges a sparkling blue and white jewel, a light, delicate sky-blue sphere laced with slowly swirling veils of white, rising gradually like a small pearl in a thick sea of black mystery. It takes more than a moment to fully realize this is Earth . . . home." - Edgar Mitchell, USA

Planet Earth, home sweet home. It is the third planet from the sun and the only known planet with life on it. The earth's atmosphere is key to life existing on our planet. It keeps the planet at a temperature where running water exists and also protects us from the harmful ultra-violet radiation of the sun. Our atmosphere is in trouble though. Since the industrial revolution we have been pouring more green house gases into our atmosphere than it can support. There are many indications that these gases may be causing a rise in the surface temperature of our planet. If we are not careful, our planet may look like the next Venus.

Earth, is the only planet in the known universe to have the conditions to contain life. The Earth is comprised of over 75% water and has 7 continents. Our planet is around 4-4.5 billion years old. 6.2 billion people inhabits this planet at the moment along with hundreds of thousands species of animals, insects and less life forms. One satellite (moon) orbits the Earth. The Earth's complete rotation around the sun is approximately 356.256 earth days. It is because of this rotation, the northern and southern hemisphere experience opposite temperature conditions during the course of the year. Many people do not know this but our planet spins at a rate of 108,000 kilometers (67,000 miles) per hour. Temperature on earth averages out to 15 degrees centigrade.

Our atmosphere is comprised of 77% Nitrogen, 21% Oxygen, and 2% others. Compared to the size of the Earth , the atmosphere is a thin shell.

A common misunderstanding about earth is the cause of the seasons. Many people believe that the seasons are a result of the planets eccentric orbit, believing that when the planet gets closer to the sun, it gets warmer and vice verse. The real reason for the seasons is that earth is tilted on its axis by about its axis by 23.5 degrees. As a result, the sun's rays are most direct on parts of the earth at different times of the year. When the sun's rays are most direct in the northern hemisphere, we experience summer (which, incidentally is when the earth is farthest from the sun). When the sun's rays shine most directly on the southern hemisphere, they experience summer and we experience winter.

When charged particles in the sun's solar wind collide with the earth's magnetic field the become trapped and are drawn to the poles. There, they collide with particles in the air and cause them to glow. These are called the aurora or northern and southern lights.