Easiest to study?
Still highly speculative!!
Start here & use Earth as a baseline for the other planets
Personal stats
Get from Appendix 9 & 10
Mass 8.2 X 10^23 grams (9 X 10^17 tons)
The moon
Actually relatively large compared to the size of the earth
An active planet
Apparent from volcanic activity
Must be internal forces still at work
Tough to study
Earthquake waves
Internal Structure - on overhead
Describe
Composition
Tied to internal structure
Zoned by density
Obviously still quite warm inside
Lots of volcanic activity
Plate tectonics - Describe in general terms
Has a strong magnetic field
Due to dynamo effect from inner/outer core
Atmosphere
Original atmosphere probably gone
Blown away by solar wind
What we have has been produced since the earth's formation
Volcanic and biologic processes, also comets
Hydrosphere
Probably the most distinguishing characteristic
Origin - Volcanic and comets
Makes life possible - Can we imagine life without water?
Composition
Density only 3.2 - same as basalt
No iron/nickel core?
Origin of moon?
Chunk of the earth's surface?
No water or other volatiles evident
All lost early in lunar history
Interior - silicates all the way through?
Apparently no volcanism or tectonics of any kind
Small quakes associated with impacts
Little or no heat flow - Basically dead
The surface
Highlands
Oldest part of the exposed lunar crust
Heavily cratered due to the accumulation of debris
Age of rock from the highlands 4.2 to 4.4 b.y.
Lunar "seas" or marias
Dark plains - covered with basalt (like earth's oceanic crust)
3.3 to 3.8 b.y. old
Most roughly circular in shape - clearly fill impact scars
All volcanic activity apparently stopped 3.3 b.y.a. - geologically dead!
Mountains - From impacts
Surface processes
Soil - Dust from impacts
No wind or water to weather or erode the surface
All shaping due to impacts
Geologic summary
Major bombardment phase - ended 4 b.y.a. w/ 6 or so major impacts (100s of kilometers across)
Volcanically active for another billion years - Created the "maria"
Flood basalt only - no volcanic mountains
Dead for the last 3 billion years
Apparently no volcanism or tectonics of any kind
Small "moonquakes" associated with impacts