FC planetary atmospheres Flashcards
(19 cards)
Describe mercurys atmosphere
mercury does not have an atmospheric layer, so it cannot retain heat. Mercury’s rotation takes 59 days so it stays in the dark and cold for quite long.
Describe mercurys composition
Atmospheric composition of mercury: He, Na and O
Describe venus’ atmosphere
Venus has a very dense atmosphere and retains most of its CO2. This means it is very hot because of greenhouse warming effect by atmospheric gases. High pressure
Describe venus’ composition
96% CO2
3.5% N2
Describe mars atmosphere
mars has very little atmosphere as the surface pressure is very low. As a result it is very cold
Describe mars’ composition
CO2 95%
N2 2.7%
Ar 1.6%
Describe the origin of the atmospheres
primordial versions of the atmosphere were made of H and He. Outgassing, evaporation/sublimation and bombardments alter the atmosphere
Define outgassing
Outgassing is the release of gases from a solid or liquid usually from a planet, rock, or material into the surrounding atmosphere or space.
What is evaporation/sublimation
evaporation - liquid -> vapour
Sublimation - solid -> vapour
What is bombardment
bombardment refers to the impact of high-energy particles or objects (like meteoroids, asteroids, or solar particles) on a planet’s surface or atmosphere.
What creates thin atmospheres
bombardment by meteorites and solar wind creates thin atmospheres
What must happens to lose a gas from the atmosphere
To lose a gas it must have sufficient kinetic energy to escape ad it needs to overcome earths gravity
Why do outer planets retain most of there original atmosphere
outer planets retain most of their original atmosphere because the large escape velocities inhibit loss
What are Jupiter and Saturn know as
gas giants
What are Uranus and Neptune known as
ice giants
How have the inner planets adapted from the primordial versions
inner planets lost the original gases and acquire their present atmosphere by outgassing, chemical modification and evolution
What is titan
Titan is saturns largest moon
Describe titan
similar size to mars has a low escape velocity allowing the atmosphere to have evolved more than that of the parent planet. There are N2 and traces of H2O and CO2 on titan but atmospheric conditions are not good enough to support life - not enough oxygen
Describe how mars lost most of its atmospheric gases
mars lost most of its atmospheric gases when it cooled and the magnetic field got weaker, no longer protecting the planet from solar stripping. Mars’ atmospher then got thiner the plater cool and H2O no longer liquid
