- The earth is protected by the atmosphere which serves as a protective shield.
- The atmosphere reflects radio waves so they can travel around the earth.
- The amount of gases included in the atmosphere took around 4 million years to evolve.
- The one percent of gases that make up the atmosphere are argon, carbon dioxide, hyrdrogen, ozone, methane, carbon monoxide, helium, neon, krypton, and xenon.
- The earth's atmosphere extends 10,000 km. from the earth's surface