14 .Habitibility (do More From Later On) Flashcards
What is the habitable zone?
Range of distances from a star which we could our planet without fundamentally changing its ability to support life
In general zone in which it’s possible for liquid water on its surface
What is atmosphere
Layer of gas surrounding a planet
How to planets get atmosphere
Volcanic outgassing, water and gassing trapped in interior during formation
Evaporation of surface liquids and ices
Micrometeorites and high energy particles
Life on earth!
How do atmospheres lose gasses
Condensation
Chemical reactions
Impacts, gasses ejected into space
Solar wind
Thermal escape because has enough energy (esc v >10 x thermal v)
Equations for thermal escape from an atmosphere
Look at lecture and practice !
Why are atmospheres important?
Liquid water depends on atmospheric pressure and oxygen
Breath oxygen
Abosorbs and scatters light
Green house affect (warms earth)
Protects from uv
Green house effect?
Sun hot emits visible light which is absorbed by planets surface
Planets are cool emit infrared radiation, atmospheres absorb and remit ir radiation , acts like a blanket
Thermal escapee, how do planets cool?
Convection, hot material expands and rises while cool material contracts and falls
Conduction, hot material transfers heat to cool material
Radiation, emergy can be lost by radiating light into space
What size planets cool faster?
Small planets cool faster than big planets
What causes Imternal heating
Differentiation- material sinks and release gpe
Radioactive decay in rocks release heat
Accretion releases gpe
Why is geological activity important?
Volcanos from tectonics for outgassing produce atmosphere
Drives current therefore magnetic field protects earth from rays
Tectonic plates
