geology Flashcards
core of terrestrial planet
- highest density
- nickel and iron
- grav pulls high density to center
mantle of rock planet
- medium density
- silicon, oxygen
crust of rock planet
- lowest density
- granite, basalt
what is the lithoshpere
outer layer of cool rigid rock that floats on soft rock underneath
3 ways a planet heats up (which is the most important)
- accretion
- differentiation
- radioactive decay (most important today)
accretion
things collide into planet converts energy to thermal heat
differentiation
light materials rise to surface, dense sink to center. convert grav potential to thermal energy
radioactive decay
mass energy converted to thermal energy
3 ways a planet cools down
- convection
- conduction
- radiation
convection
transports heat up and cool down
conduction
transfer hotness through cooler surfaces
radiation
sends energy to space
planet size and geo activity
- smaller worlds cool faster
- large world has more volcanisim and erosion due to atmosphere
requirements for planet to have a magnetic field
- molten interior
- convection
- moderate roation
why does venus not have a mag field
rotates too slow
why doesnt mars have a mag field
no convection
cratering
- happens early in planet life (1st billion years)
- world like moon that has many craters has not changed much
- 10x wider than obj that created it
- lava floods can cover up craters
volcanism
- releases gases into atmosphere
tectonics
- caused by convection
- creates mountains, valleys
- created cliff of mercury
erosion
- weather stuff
- glariers
- rivers
- wind
distance from sun affects geo activity
- close to sun less erosion, less atmospshere
- far from sun less erosion
slow roation
less erosion, weak mag field
what is atmosphere
- thin layer of gas surounding planet
- no clear boundry
earths atmo
- 10km thick
- mostly N2 O2
- 100km = space
