Uranus


Key points

Size
diameter - 4x>
mass - 17x>

Gravity - .8

Distance - 19 AU

Revolution - ~165 yrs

Axial Tilt - ~98o

Rotation - retrograde b/c axis of rotation is >90o
almost flat to the plane of the solar system (8o below)
sometimes one pole faces the sun then it changes
~17 hrs, but this took time to resolve and
the interior rotates slower

Atmosphere - methane
looks blue-green b/c methane absorbs red light
poles show photo disassociation

Magnetic Field - strong (50x>)
extends 18x radius vs 10x
not aligned (59o) from rotational axis
8,000 km off centered
and nobody knows why
its changing directions
hit by Earth size planet and tipped on its side
field originates in a thin shell outside a rocky core

Surface
dark polar cap
cold chemical reactions
planet accreted around rocky and ice planetesimals

Rings
Discovered 5 in 1977 during a occultation of a star
Discovered 4 more in 1987 during a retrograde occultation

Very narrow
Have shepherd moons
young -> 100 MYO
dust like - impact debris?

Satellites ~15?
all rotate synchronously