An Overview of the Universe

Lets start with the basics
We live on a planet called Earth. It is located in a solar system of 8 planets and a sun.

Our solar system is part of group of stars and planets called the Milky Way Galaxy. Our milky way is a spiral galaxy, a flat disk with a big ball at the center with a diameter of 100,000 light years. Scientists do not know how many stars are in our galaxy. A recent estimate in 2009 puts the number of stars as high as 3 trillion. The picture below are what scientists believe our galaxy looks like. The top picture is a top view and the bottom picture is a side view. Notice where the Sun is.

The Sun is revolving at a speed of half a million miles per hour (500,000/mph) around the center of the Galaxy, yet it will still take 200 million years for it to go around once.