Including...
The Earth/Moon system (a separate file)
The innermost planet
One of the brightest objects in the sky
But rarely seen - WHY? (Never more than 28 deg. from the sun)
Fastest moving of the planets (named for the Greek & Roman God of Speed)
Orbits sun in 88 earth days at 48 km/s
Orbit is most varied of all planets (except Pluto)
Highly eccentric (0.206)
Perihelion: 46 million kilometers
Aphelion: 70 million kilometers
Also, inclined 7 deg. to plane of ecliptic
Very small, but with a similar density to earth (5.5)
Seems to be similar in composition to earth, but different proportions
Core accounts for 60% of its total mass (fig 13.22, pg. 230)
Basically a small metal ball with a thin silicate crust
Surface features
Quite a range of temperatures
Up to 400 deg. C at 'noon'
Proximity to sun supplies the daytime heat
Drops to -175 deg. C just before dawn
Lack of atmosphere allows the heat to escape at night
This would give your heat pump a real workout
Heavily cratered like the moon
With areas that have been flooded by basalt
Volcanics very early in planets history (4 b.y.)
No evidence of plate tectonics
Isolated 'scarps' indicate shrinkage during cooling (fig. 13.25, pg. 232)
General tectonic history indicates:
Early expansion while hot
Releasing basaltic flows
Later shrinkage during cooling
Causing scarps due to compression/contraction
Very similar to earth on overall features
Physical features nearly identical (Table 15.1; pg. 258)
Surface is only lightly cratered
Dominated by volcanic activity
Definite "continents" as on earth (2 of them)
Indirect evidence for surface water in the past
One difference is its retrograde rotation
"One of the most beautiful objects in the night sky"
Named for the Goddess of Love and Beauty
Beauty is clearly "only skin deep" because its a rather ugly place at the surface
Extremely harsh surface conditions
Temperature well above 400 deg. C
Atmospheric pressure 90X that of earth (we would implode!)
Both the result of the extremely dense atmosphere (96% CO2)
Thick cloud cover is the result of H2SO4 droplets in the atmosphere
Probably derived from extensive volcanic activity
Greenhouse effect
DIGRESS TO: runaway greenhouse effect
Venus used to be more like Earth
Almost certainly had large amounts of surface water
Initial slow surface heating due to small increase in atmospheric CO2
Leads to increased evaporation and H2O content in air
Leads to more heat retention, and the "Runaway Greenhouse Effect" cycle
Carried to its logical conclusion...
Leads to evaporation of any surface waters and a "hot water" atmosphere
Water vapor is not stable in UV light and breaks down into atomic form
Hydrogen escapes into space
Oxygen combines with iron, etc. at the surface
Therefore, the loss of surface water is permanent
Could this happen on the earth?
The "red planet" named for the God of War
Much smaller than the earth
Approx. 11% earth's mass
Atmosphere similar to Venus in composition (95% CO2)
But not in density - .006 bar (Mars) to 1 bar (Earth) to 90 bar (Venus)
Surface similar to earth 200 mya when Pangea was complete
Southern highland (continent) which is heavily cratered (probably older)
Surrounded by younger volcanic plains (not covered by water)
Several kilometers lower in elevation than the "continent"
Extensive tectonic and volcanic activity
No direct evidence of plate tectonic activity
Several features indicating tectonic/volcanic activity
Most 1-3 billion years old
Tharsis Bulge - active region the size of North America
Concentration of "recent" volcanic activity
Olympus Mons (fig. 14.8, pg. 241)
Probably largest volcano in solar system (fig. 15.14, pg. 268)
Possibly still intermittently active!
Valles Marineris (fig. 14.10, pg. 243)
A tectonic feature so not really a "valley"
Basically tension cracks on the edge of the Tharsis Bulge
Similar to tensional features in Africa
Big! 5000 km X 100 km X 7 km deep
Possibly plate-style activity may have started long ago
Did not develop like on earth due to smaller mass, quicker overall cooling
Much evidence for surface water (See: photo pg. 234; fig. 14.8b, pg. 241)
Most drainage features limited to older cratered highland areas
Two kinds of drainage patterns
Normal dendritic patterns (fig. 14.12, pg. 244)
Developed on the older cratered upland areas
Evidence for catastrophic floods (fig. 14.21, pg. 250)
From the upland onto the lava plains
Like the Channeled Scablands of Eastern Washington
Evidence for glacial ice ages in the Martian past?
Supports theory that surface water was present during 2 periods in the past
The first 4 billion years ago related to "normal" rainfall/runoff
Then later a sudden release of frozen water by volcanic heating, or?
All surface water now frozen into polar ice caps (fig. 14.2, pg. 236)
Possibility for life in the past (maybe now?)
Mars has been the origin of some of earth's most fearsome alien creatures
Invaders From Mars, War of the Worlds, My Favorite Martian
None identified by any of the Martian probes
Intense UV from sun would make "life as we know it" unlikely
However, "water is life" and Mars has water
Stay tuned for an update
General features of Jupiter and Saturn
Largest planets in our solar system
Jupiter is almost a binary partner to the sun
Each has a system of orbiting satellites (moons) and rings
Can be quite extensive
Saturn has an impressive ring structure and 19 moons
Basically mini-suns - Composed of hydrogen and helium
Theoretical internal structure - fig. 16.3, pg. 277
Pressure at depth compresses the hydrogen into liquid, then "metallic" form
With a small "ice and rock" core
Central cores may represent the original rock/ice bodies which accumulated from the nebula
With the hydrogen being "captured" at a later time
Not "rock" as we recognize it due to extreme pressure and temperature
Some form of iron, silica, and oxygen
The "ice" is also probably different from what goes into a glass of Pepsi
Any combination of hydrogen with carbon, nitrogen, or oxygen
Both radiate impressive amounts of heat from 2 sources
Residual heat from the initial condensation of the nebula
Newly generated heat from continued contraction of the gas
Well developed "atmospheres"
Hydrogen and helium, with methane (CH4) and ammonia (NH3)
In orbit: 16 moons, faint ring
Has an extensive cloud cover
Vivid colors (white, orange, red, brown)
Essentially condensed ammonia (anyone for a walk in the rain?)
Great Red Spot (fig. 16.2, pg. 276) and (fig. 16.12, pg. 284)
A large "storm" in the atmosphere - almost 30,000 km across!
Has been "stable" for at least 300 years
How can it last for so long?
Nothing solid to interfere with the circulation of the gas
In orbit: 19 moons. extensive rings
In orbit: 15 moons, intricate system of dark rings
In orbit: 8 moons, faint rings
Great Dark Spot: similar to GRS on Jupiter
Atmospheric storm 10,000 km across
Discovered after a systematic search
Its presence was indicated by "wobbles" in Neptune's orbit
In orbit: a single large moon (Charon)
Essentially a binary system