Planetary AtmospheresPlanetary Atmospheres

Terrestrial PlanetsTerrestrial Planets

VenusVenus

Completely cloud Completely cloud shroudedshrouded

Surface Surface atmospheric atmospheric pressure 100 pressure 100 times Earth’stimes Earth’sSurface temp:Surface temp:

870870oo F F

MarsMars

Extremely thin Extremely thin atmosphereatmosphere

Surface pressure Surface pressure .007 times Earth.007 times Earth

Surface Surface Temperature Temperature

-58-58oo F F

Gaseous atmosphere

No real ‘surface’

Liquid and metallic

hydrogen interior

Earth sized core

JupiterJupiter

Holding an AtmosphereHolding an Atmosphere

A bunch of Hydrogen gas (very light) and a A bunch of Hydrogen gas (very light) and a bunch of Carbon Dioxide gas (very massive) bunch of Carbon Dioxide gas (very massive) are at the same are at the same temperaturetemperature. Which has . Which has the greatest the greatest velocityvelocity? ?

A.A.HydrogenHydrogen

B.B. Carbon DioxideCarbon Dioxide

C. They have the same velocity.C. They have the same velocity.

Kinetic EnergyKinetic Energy

Which has more Kinetic Energy?

A) Bowling BallB) BaseballC) They have the same amountD) Can’t tell

Thermal EnergyThermal Energy

TemperatureTemperature: : The averageThe average kinetic energykinetic energy of a of a collection of particlescollection of particles

Gas PressureGas Pressure

Atmospheric pressureAtmospheric pressure

Planetary TemperaturePlanetary Temperature

Planetary TemperaturePlanetary Temperature

Planetary TemperaturePlanetary Temperature

Hot Things Emit LightHot Things Emit Light

Hotter = MORE lightHotter = MORE light

Hotter = Bluer LightHotter = Bluer Light

Planetary TemperaturePlanetary Temperature

Energy in = Energy out

Planetary TemperaturePlanetary Temperature

Planetary TemperaturePlanetary Temperature

Terrestrial Planets emit Terrestrial Planets emit PRIMARILY Infrared lightPRIMARILY Infrared light

The AtmosphereThe Atmosphere

The atmosphere passes visible The atmosphere passes visible lightlight

And absorbs infrared lightAnd absorbs infrared light

Greenhouse EffectGreenhouse Effect

Yum!IR Photons!

Greenhouse EffectGreenhouse Effect

The greenhouse effect keeps a planet The greenhouse effect keeps a planet warmer than it would be without and warmer than it would be without and

atmosphereatmosphere

VISIBLEVISIBLE light passes through the light passes through the atmosphereatmosphereThe ground The ground ABSORBS ABSORBS the visible light the visible light and warms upand warms up

The warm ground The warm ground EMITS EMITS primarily in primarily in the IRthe IRGreenhouse gasses Greenhouse gasses ABSORB ABSORB IR light, IR light, effectively trapping some of the energyeffectively trapping some of the energy

Atmospheric COAtmospheric CO22

Global WarmingGlobal Warming

The ‘Hockey Stick’The ‘Hockey Stick’

MoulinMoulin

GreenlandGreenlandGreenland’s ice would raise ocean levels Greenland’s ice would raise ocean levels

20 feet20 feet

Larson Ice ShelfLarson Ice Shelf

BreidamerkurjökullBreidamerkurjökull

This glacier in Iceland has receded 2km This glacier in Iceland has receded 2km since 1973since 1973

19731973 20002000

Pasterze GlacierPasterze Glacier

18751875 20042004

PermafrostPermafrostPermafrost is melting in several areas. Permafrost is melting in several areas.

The resulting bogs produce methane.The resulting bogs produce methane.

Denali Park, Denali Park, AlaskaAlaska Abisko National Park, Abisko National Park,

SwedenSweden

TemperatureTemperature

Measures average KINETIC Measures average KINETIC energyenergy