Done by Patrick Yen (2P431)

What is an atmosphere?An atmosphere is a layer of gases

surrounding a material body of sufficient mass that is held in place by the gravity of the body.

However, some planets consists mainly of gases, for example Jupiter and Saturn. So only the outer layer is their atmosphere. These planets are called gas giants.

Atmospheric pressureAtmospheric pressure is the force of per unit

area that is applied perpendicularly to a surface by the surrounding gas. It is determined by the planet’s gravitational force combined with the total mass of the air above a location.

So the higher the altitude, the lesser the atmospheric pressure as the mass of air declines at high altitude.

Atmosphere of the EarthThe atmosphere of the Earth

protects life on Earth by absorbing ultraviolet solar radiation, trapping heat (greenhouse effect) and reducing temperature extremes between day and night.

It includes five principle layers: the Exosphere, the Thermosphere, the Mesosphere, the Stratosphere and the Troposphere.

Earth’s atmosphere contains mainly Nitrogen, at approximately 78% and Oxygen at about 21%. The rest are Carbon Dioxide and other gases. These gases are known as trace gases. Trace gases make up less than 1% of the atmosphere.

Atmosphere of other planetsApart from Earth, other planets also have an

atmosphere, including extra solar planets. Even the moons have atmosphere, like Saturn’s moon Titan.

However, they are dangerous for living things as they have are different from Earth. For example Mars. Its atmosphere consist mainly of Carbon Dioxide, at about 95% and Oxygen at about 0.1%, and its pressure is too low.

Although the atmosphere of other planets are dangerous, there is a way which may be possible to modify the atmosphere of a planet, called terraforming.

However, terraforming requires much more economic resources than any government or society is willing to allocate to the purpose.

Also, the feasibility of creating an atmosphere that mimics Earth on another planet has yet to be verified.

Anyway, the atmosphere is really important to us.However we humans still are not cherishing it. It is true that many people are trying to stop the pollution of our atmosphere, but there are still many people who do not care. If only everyone on this planet can do their part, our atmosphere will not be destroyed.