Planetary Breakdown
Mercury
Atmosphere & Weather: no atmosphere or negligible.
Extreme temperature variation due to lack of atmosphere.
Ice found on Mercury. How? Comets...survived in shadow of craters.
Geology: Surface is Fractured (huge scarps) and heavily Cratered
Caloris Basin: One of largest impact craters in the solar system (ca. 1500km
diameter)
Moons – none known.
Orbital Mechanics-- revolve quickly but rotate slowly..
Venus
Carbon Dioxide is predominant atmospheric gas. Also contains sulfuric acid
which gives it a yellowish appearance.
Earth’s sister planet: mass, radius and density closely resembles that of earth.
Atmospheric differences give rise to drastic differences in surface conditions.
Volcanic activity has given Venus a thick atmosphere
Atmosphere is much thicker than on earth. About 90x the atmospheric pressure
on earth. This is comparable to water pressure 1000 meters below ocean
surface.
The immense pressure could create optical illusions of walking downhill.
Plate tectonics on venus?. No (lacks magnetic field, lacks water,
asthenosphere,). Radar images suggest against it.
Day is longer than its year
Immense weathering and erosion.
Earth
Outer layer is crust, thin layer less than 100 miles thick
Direct sampling of crust = 3g/cm^3
Crust is made of separate plates
Motion of these plates is plate tectonics
The borders of these plates can give rise to mountains or rift zones (e.g. mid
atlantic ridge).
Metallic iron core rotating generates magnetic field.
Mars
Same rotational period of the earth
Signs of water in form of dried up river beds, fog, permafrost and polar ice caps.
Probably lacked liquid water for millions of yeas.
Polar ice in caps is accompanied by carbon dioxide (dry ice)
Water sublimates there because the pressure is too low (dry ice)...Ice to vapor..
Mars is called the red planet...apparent even on earth.
Color from the surface composition which contains oxidized iron (rust).
Seasonal dust storms dues to intense temperature gradients.
Olympus Mons--giant dormant volcano on mars largest in SS.
Two moons, really small, Phobos and Deimos.
Jupiter
5x E-S distance, year is 11.9 earth years and day is 8hr 56 min
rocky core? overlaid by metallic hydrogen
Galilean suicide probe informative.
Small ring system
Galilean Moons (Ganymede, Calypso, Io and Europa
IO -volcanically active--mostly sulfur--sulfur volcanoes (changes color as it
heats)..white stuff is settled dust.
Close orbit causes high gravitational tidal effects and produces heat
First time seeing active volcano outside earth
Saturn
The beautiful ringed planet...low density (could float in a big enough bathtub)
Galileo didn’t see rings due to their tilt at that time. Planet w/ ears.
Saturn has 18+++moons—
Titan larger than Mercury or Pluto
Titan has a dense atmosphere, more dense than Earth’s.
Uranus
Made mostly of methane
Is titled on its side almost 90 degrees, hence 42 year polar seasons.
Rings discovered by their eclipsing of stars (9 times for 9 rings).
Small dense core, water that is high pressured and is a electric
Differential rotation like on sun (equator rotates faster than poles)
The electric currents produce a magnetic field that is off set to planet’s spin.
Miranda--took big hit and reassembled but did not differentiate
Lack of heat to differentiate after collision led to jumbled gobstopper surface.
Neptune
Highest winds in solar system
Had moons and rings discovered by Saturn...
Large blue spot largely disappeared...has white spot and it moves...
Bright and Dark clouds via internal convection
Pitch Black when you get out here (sun is faint object)
Triton has an atmosphere---but unlike Titan its very thin.
Complex surfaces...Methane Snow Fields...
Pluto
Not really a planet?--dwarf planet.
Started by Percival Lowell in 1905, but Tombough in 1930
Revolves once every 247.7 years--5.9 billion km. Rotates in 6 days.
Eccentric Orbit---comes closer than Neptune at times.
Orbit tilted 17.2 degrees with respect to ecliptic plane--never collide.
Light and Dark patches--kind of like dirty snowball.
Has a moon, Charon--but moon is very large compared to pluto.
Pluto has very slight atmosphere at perihelion...thin atmosphere.
Moon is close enough that they can share that atmosphere.