Earth's Atmosphere

Earth's atmosphere is very different from the moon or a planet without an atmosphere. Earth can protect life as we develope and provide oxygen for respiration. The moon has no atmosphere, so metereoids aimed at it hits and remains unchanged for billions of years. If a meteorite enters Earth's atmosphere it might burn up before reaching Earth depending on its size. When meteors don't burn up and hits Earth, the crater will almost disappear in much less time than on the moon. The major components of our atmosphere are nitrogen, oxygen, and a small amount of something incombustible. It contains matter such as dust, volcanic ash, rain, and snow. A green house effect absorbs heat admitted by the Earth warming the atmosphere. There are four layers in the atmosphere. The bottom layer is the troposphere where all weather occurs. The ozone layer warms air around it and protects us from harmful UV radiation. Stratosphere is where aircrafts fly bacause it is very stable. In the mesosphere the temperature decreases from the density of air and this is where meteors burn up. The top layer is the thermosphere with auroras and where the space shuttle orbits. Pressure decreases with altitude. The presence of oxygen and water vapor makes our atmosphere a unique place.

Uranus

Space Exploration

Space Exploration

The Science of Rockets

Since the late 1950s, Atlas rockets launched prons into space and satellites into orbit. They have three stages, the first one is called Atlas which uses both solid fuel and liquid fuel engines to launch the payload into space. Centar, the second stage uses liquid fuel engines to maneuver into orbit. The final stage is the satllite or spacecraft carried by the rocket, also called payload.

The Space Program

The National Aeronautics and Space Administration (NASA) launched Apollo 13 on April 11, 1970, An oxygen tank blew up two days later, but they had enough oxygen and landed safely in the Pacific Ocean. There are three other spacecrafts that visted the moon, Galileo, Clementine, and Lunar Prospector.

Exploring Space Today

A small robot called a "personal satellite assistant" was planned for the International Space Station. This robot floats next to the astronaut and can tell them temperature, pressure, air quality, and potential problems in the space system environment. It also has a "videophone" that allows astronauts to communicate with each other and also is linked to Mission Control on Earth.

Using Space Science on Earth

NASA officials estimate that for every dollar invested, the U.S. economy recieves $7 in return for job creation, economic growth, and taxes. Many people argue against funding the space program and believe the money would be better spent elsewhere. The NASA counter these arguments by saying space exploration gives us a better understanding of Earth, support many jobs, good for ecomony, and an inspiration to humans.