Uranus Flashcards
1
Q
uranus physical characteristics
- diameter
- avg. dist. from sun
- mass
- orbital pd
- rotational pd
- # of moons
- magnitude
A
- diameter = 4 x earth
- avg. dist. from sun = 19 AU
- mass = 14.5 x earth
- orbital pd = 84 yrs
- rotational pd = 17.25 days; differential; retrograde
- # of moons = 27
- magnitude = 5.3
2
Q
uranus atmosphere (4)
A
- bland, blue-green world bc methane absorbs red light
- mostly hydrogen w/ some methane & high-altitude haze
- under haze = clear air w/ methane clouds
- presence of lightening
3
Q
axial tilt (3)
A
- rotation axis = tilted 98 degrees from orbit perpendicular
- north pole = titled below orbital plane
- extreme tilt = cause for seasonal variations in its weather
4
Q
retrograde rotation (2)
A
- as it orbits the sun, n. & s. poles alt. point directly toward or away from the sun
- gives uranus very long seasons (about 20 years each)
5
Q
interior (3)
A
- 3 layers
- atmosphere lies atop 1st layer
- little ammonia in atmosphere bc it is dissolved in 2nd water layer
6
Q
3 interior layers
A
1- outer 30& = liquid hydrogen & helium
2- next 40% inward = highly compressed liquid water w/ some methane & ammonia
3. inner 30% = rocky core
7
Q
alternate interior description (2)
A
- new evidence says 2nd layer is nonexistent
- composed of rock & ices w/ only 15% hydrogen & little helium
8
Q
magnetic field (3)
A
- @ cloud tops = 3/4 strength of earth’s field
- magnetotail is twisted by uranus’ rotation into corkscrew shape
- field’s source is unknown
9
Q
magnetic field’s axis tilt (4)
A
- field tilted 59 degrees from rotation axis
- field’s axis doesnt pass thru center of planet (unusual)
- means field wobbles as uranus rotates
- wobble allows rotation rate of interior to be measured
10
Q
magnetic field’s rotation rate (2)
A
- uranus’s field rotates in 17 hr & 14 min
- cloud layers rotate in 16 hrs & 30 min
11
Q
ring system (6)
A
- orbited by 13 thin, dark rings
- each ring composed of ringlets
- orbit in plane of equator
- held in orbit by shepherd moons
- has a pair of giant rings
- dim & dark bc they’re mostly dust rather than ice
12
Q
moons
A
-most orbit in plane of uranus’ equator
13
Q
miranda description & orbital pd (2)
A
- innermost & smallest of major moons
- orbits in 1.5 days
14
Q
miranda composition (2)
A
- 1/2 water ice
- remainder divided b/t rock & methane-related organic compounds
15
Q
miranda surface (3)
A
- surface = unusually wrinkled & banded features
- varied terrain = broken into many pieces by impact, then pieces re-coalesced
- or tidal heating moved lg. pieces of the crust
