The Cosmic Perspective Chapter 10 - Lecture 20

X Rays photons

Ionize and knock electrons off almost any gass

Dissociate/break apart absorbed molecules

Ultraviolet Photons

Molecules break apart when they are absorbed

Visible Light Photons

Slighty transmitted, some are scattered

Infrared Photons

Absorbed by molecules and greenhouse gases

Causing vibration and rotation

Exosphere

Not much there

Heated by X rays and UV

Absorbs X rays

Atoms can escape without hitting other atoms

Fast moving gas molecules can escape into space

Thermosphere

Starts to cool down again, Gets really hot

Absorbs X-Rays, break up atoms

Ionosphere reflects radio waves

Xrays ionzie gases

Ionosphere almost disappears at night due to lack of x-rays

Stratosphere

Ultraviolet molecules absorbs the Ozone layer

Ultraviolet Breaks up/dislocates weak molecules

Energy Heats up the layer

No convection

Troposphere

Visible light passes through to heat the surface

Gives off Infrared

Greenhouse gases absorb the infrared

Infrared molecules vibrate and rotate that increases temperature

Main gas responsible for the green gas effect on earth

water vapour

Greenhouse effect

Warms Venus, Earth, and Mars

Occurs in the tropophere

Greenhouse effect in venus

Very Strong

But undesirable because the planet is too hot to live

Greenhouse effect in earth

Moderate

Warms up layer to a desirable amount

Greenhouse effect in mars

Weak

Would be too freezing to live here.

Magnetosphere

Requires magnetic field

Electricity conducting core, convection rotating

Contains ions and electrons - Charged particles

Causes Auroras

Can protect an atmosphere

Magnetic Field Requirments

a molten

Convecting

Conducting Core

If it has an atmosphere but no magnetosphere

Solar wind can penetrate the atmosphere, striping it away

If it has no atmosphere but no magnetosphere

The solar wind can strike the surface

enema lava

the more you heat it up, the brighter it is

Light extends into shorter wavelengths

What factors can change a planet's temperature over billions of years?

Changing the distance from the sun

Reflectivity - can get lighter/darker

Changing the degree of axis tilt

Change in greenhouse gas amounts

Change in the brightness of the star

3 sources of atmospheric gas

Outgassing

Evaporation/sublimation

Bombardment

Types of planets that source gas

Large Terrestrial Planets. Volcanism

Outgassing

Release lots of H2O, some co2, a little of n2

trapped in interior rock by volcanic

Large terrestrial planets have warmer interiors that led to volcanos

Only venus and mars

Evaporation/sublimation

Liquids/ices turn to gas when heated. Happens when planets has ice or water - Earth and Mars

Bombardment

Surface ejection of micrometeorites,

blast atoms/molecules out of surface rock

Planets with no substantial atmosphere - Moon and Mercury

Main gases

H20 and Co2

Oxygen

Nitrogen

Types of planets that lose gas

All planets lose atmospheric gas no matter what. It's the way how they lose gases are different

4 ways to lose atmospheric gas

condensation

chemical reactions

SW stripping

thermal escape

condensation

Gas turns into liquids/ices on the surface when cooled. Earth and Mars

chemical reactions

Gas is bound into surface by rocks or liquids. Planets that has liquid, Earth, Mars (only a little bit)

SW stripping

Gas knocked out of exosphere by solar wind. Forever effect - Mars, Venus, Mercury, the Moon.

thermal escape

Lightweight atoms lost to space when they escape velocity. Forever effect. Smaller Planets, Mercury and the Moon

The life of the planet

depends on limestone

Chemical reaction that removes carbon dioxide from the atmosphere now on the sea floor