Earths Atmosphere Flashcards
Atmospheric Composition
Earth is the only only planet with a atmosphere that can support life.
This is due to the the unique compositions of gases in the atmosphere.
Earth’s atmosphere consist:
Nitrogen: 78%
Oxygen: 21%
Argon: 0.93%
Carbon-dioxide: 0.04%
Trace amounts of helium, neon, hydrogen, methane, krypton and water vapour.
Atmospheric layers
Troposphere
Stratosphere
Mesosphere (meso=middle)
Thermosphere
Exosphere
Troposphere
Layer that is closest to earth.
Consists of approximately half of the Earth’s atmosphere.
Almost all of the water and dust are found in this layer, forming clouds.
Where most of the Earth’s weather is controlled and created.
Stratosphere
Air is drier and less dense.
Air crafts usually fly in the low stratosphere to escape the turbulence in the troposphere.
Mesosphere (meso=middle)
They layer that protects the earth from meteors
Thermosphere
Space shuttles and satellites orbit within this layer.
A person in this layer is considered and astronaut.
Aurora’s take place in this layer.
Exosphere
Outermost and lese dense atmospheric layer.
No definite outer layer limit as it merges with space.
Many satellites orbit the earth within the exosphere.
Ozone Layer
Blue gas made from three oxygen atoms.
It absorbs most harmful ultra-violet radiation from the sun.
It is found between the stratosphere and the troposphere.
Altitude is only 20km, meaning there is a higher concentration of the ozone layer.
Area of concentration is referred to as the ozone layer.
Thinning in the ozone layer can result in, changes in the Earth’s climate, in particular temperature.
This is referred to the hole in the ozone layer.
Ultra-violet radiation
Ultra-violet radiation is the radiation emitted by the sun.
Classified into 3 groups:
UV-A: Ozone layer is transparent to this UV wavelengths so it reaches Earth. This type of UV is significantly less harmful to DNA but can indirectly cause skin cancer and premature skin aging.
UV-B: Excessive exposure can cause cataracts, immune suppression, sunburn and skin cancer due to genetic change.
UV-C: Highest form of radiation and is harmful to all living things, but is screened out by oxygen (O2) and ozone (O3)
UV-Radiation
Ultra-violet radiation light has higher energy compared to visible light. It is this high energy component of sunlight that damages the tissues.
When UV radiation is absorbed by our cells, it causes electrons in cellular components to be excited.
The human body has evolved to deal with UV damage, but if the damage outweighs the body’s ability to repair it, or the repair mechanism itself is damaged, then signs will start to appear.
Protection Against UV radiation
Some strategies to prevent against skin damage are:
Avoid the sun during peak hours (10 am - 2pm)
Seek Shade
Wear clothing with a broad spectrum, e.g. water resistant, UPF of 50+
Use sunscreen year around. Some of the worst burns occur in winter.
Apply sunscreen 15 minutes before going outdoors. It takes 15 minutes for the sunscreen to be absorbed by the skin.
