Q2: Lesson 2: Atmosphere

Early Earth

• inhospitable

• frequent asteroid and meteorite bombardment

• frequent volcanic eruptions

• very high temperature causing hydrogen and helium to escape

• lots of water vapor with no oxygen

Later Earth

• frequent volcanic eruptions produced water and gases such as carbon dioxide, carbon monoxide, nitrogen, hydrogen, ammonia, and methane

• still no oxygen

As the Earth Cooled

• water condensed to form oceans

• carbon dioxide dissolved into oceans forming carbonates

• nitrogen became a major component

Present-day Earth

mainly composed of nitrogen and oxygen with trace amounts of several gases

Nitrogen

the most abundant gas

Oxygen

the second most abundant gas

Troposphere

• lowest layer

• most water vapor

• all weather associated cloud types

• temperature decreases, altitude increases

• clouds get thinner and absorbs less radiation

Stratosphere

• above the troposphere

• temperature increase, altitude increases

• presence of ozone

• where jet planes fly

• lacks weather-producing air turbulence and is almost free of clouds and other forms of weather

Ozone

protects the Earth by absorbing ultraviolent radiation

Mesosphere

• temperature decreases, altitude increases

• protects Earth from meteoroids

• meteorides that enter the Earth burn up due to intense friction

Burning Meteoroid

“shooting star” or “burning meteors”

Meteorites

meteoroids that manage to reach Earth

Thermosphere

• second highest layer

• temperature increases, altitude increases

• nitrogen and oxygen absorb a great deal of ultraviolent radiation and turns it into heat

Ionosphere

consists of highly-ionized gas which was formed when ultraviolent rays knock off electron from nitrogen and oxygen

Kennelly-Heaviside Layer

layer of the ionosphere that reflects radio waves

Aurora

• colorful display of lights formed when ions interact with air molecules, usually happens at the poles

• Northern Lights - Aurora Borealis

• Southern Lights - Aurora Australis

Exosphere

• outermost layer

• most of the orbiting satellites, as well as low density elements, like hydrogen and helium are found here