Planetary atmospheresCHAPTER 10 SECTIONS 10.1 & 10.2

Discuss the factors that affected the geologic processes and formations of the planets

Outline the information in the 6 slides

Use Chapter 10, sections 10.1 and 10.2 , pages 280 - 295 to add further detail.

Highlight the detail that you add

Refer to your vocabulary to be sure you understand the concepts

Planetary Atmospheres

Planetary Atmospheres

What is an atmosphere? the layer of gases that

surround a world can be either molecules or

atoms which create pressure-we feel the pressure of 1 atm, on Venus we would feel the pressure of 90 atmospheres

Where does the atmosphere end?

There’s not a specific ending place-it kind of fades away

Atmospheric Structure

3 factors that determine how sunlight would heat a planet with no atmosphere:

1. Distance from the Sun the closer it is, the more energy

from sunlight reaches the surface

2. How much sunlight the planet absorbs vs. reflects

3. How fast the planet rotates if it has a short day, the

temperatures will be more even than if there is a really long day

Atmospheric structure

How does an atmosphere keep a planet warm?

Gases can absorb infrared light and heat up

Greenhouse gases trap infrared radiation and this helps heat the lower atmosphere (where we live!)

The greenhouse gases are gases that are good at absorbing infrared light: Water vapor Carbon dioxide Methane

10.1 Atmospheric Structure

Layers of the atmosphere

10.1 Atmospheric Structure

How does the fact that our atmosphere scatters light benefit us? What would it be like if our atmosphere didn’t scatter light?

Without scattering we would be able to see the stars during the daytime!

Also, shadows would be pitch black, so walking down the alley in a big city would be like night!

Atmospheric Structure

Why is the sky blue? Light scattering

makes the sky appear blue

Blue light is scattered while the red light goes straight through the atmosphere

Atmospheric Structure

Why do sunsets appear red? Sunlight passes through more

atmosphere to reach you-most of the blue light is “scattered away” leaving the red behind.

10.1 Atmospheric Structure

 Why is the stratosphere called the stratosphere?

 There isn’t any convection, so the air isn’t moving much and becomes layered-AKA stratified

Airplanes glide smoothly here because of the lack of air movement.

How does the ozone in the stratosphere benefit us?

It absorbs most of the Sun’s UV radiation, which is very damaging to us

Atmospheric Structure

Figure 10.9 Very important!! a. Which one of the three

planets shows the biggest temperature increase due to the greenhouse effect?

b. Which planet has the most uniform temperature from high to low altitude?

c. Is the Earth’s temperature higher at and altitude of 25km or 50km?

Magnetospheres and the Solar Wind

Why is the magnetosphere so important to us?

Solar wind = charged particles from the Sun The magnetosphere will either divert those

particles or trap them in the Van Allen Belts

They can produce beautiful auroras in the North and South poles-where the North and South poles of the magnetosphere come close to the Earth’s surface

MAGNETOSPHERES AND THE SOLAR WIND

  Weather and Climate What is the difference between

weather and climate? Weather is the varying

conditions and combinations of wind, clouds, temperature, and pressure

Can change with the seasons and atmospheric conditions, can vary dramatically by the month, day or even hour

Climate is the long term average of all the weather in an area and generally stays the same over long periods of time

What are the 2 major factors affecting global wind patterns?

Atmospheric heating: the air at the equator heats and expands, then flows towards the poles and sinks, creating convection cells

Rotation and Coriolis Effect: Coriolis effect alters the path of the air due to the rotation of the Earth like a merry go round

10.2 Weather and Climate

The circulation of the Venusian atmosphere is dominated by two huge convection currents in the cloud layers, one in the northern hemisphere and one in the southern hemisphere

What are the 2 major factors affecting global wind patterns?

Planetary rotation: basically the rotation of the planet pushes the air sideways-called the Coriolis effect

Weather and Climate

How does the Coriolis effect change the shape and movement of the circulation pattern of winds on Earth? Breaks up the convection

cells so there are 6 instead of 2 (3 per hemisphere)

Causes air to circulate counter clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere

10.2 Weather and Climate

How are atmospheres created? From 3 different processes

Outgassing-the outpouring of gases from the earth's interior

Evaporation/sublimation-surface liquids evaporate into the atmosphere

Bombardment-micrometeorites can create only a very thin atmosphere, this is the main source of atmosphere for the Moon and Mercury

  Atmospheric Origins and Evolution

10.5 Atmospheric Origins and Evolution

Outgassing from volcanism on Earth, Venus and Mars releases water, carbon dioxide, nitgrogen and sulfuric gases

Evaporation and sublimation from the surface adds gases as the planet surface warms

Bombardment by micometeorites ejects surface materials including gases and explains even the small amount of atmosphere around the Moon and Mercury

Gaining Atmosphere

10.2 Atmospheric Origins and Evolution

Thermal escape occurs as particle are heated and reach escape velocity

Bombardment and atmospheric cratering result from solar wind particles stripping.

Condensation of atmospheric gases on the surface occur with cooler temperatures. Mars has dry ice on its surface

Gases chemically react with the surface, like oxygen

Losing Atmosphere

What are the 3 factors that determine if a gas can be lost by thermal escape?

1. The planet’s escape velocity-the larger the planet the stronger the gravity

2. Temperature-higher temperature means faster movement

3. Mass-it’s easier for lighter particles to move fast enough to escape

Atmospheric Origins and Evolution

 Reflection-Extra Credit! What makes our

atmosphere so unique and suitable for life?

Give at least 4 pieces of evidence to support your claim.

Include information on the atmospheres of at least 2 other terrestrial planets in comparison with Earth.

Terrestrial Atmospheres