Geology of the Solar System
•The Sun
•109 times the diameter of the Earth!
•333,000 times the mass of the Earth!
•Burns hydrogen to helium
•E=mc2 means small amount of mass converts into a lot of energy
•Temperature at surface is 5,800 K
•At the center, the temperature is 15 million K
•Convection causes surface granulation (cells)
•Sunspots
•~10,000 km across
•Red center with an orange ring
•Linked to intense magnetic fields
•On an 11-year cycle
•Solar wind
•Fast moving (1 million km/hr) gas in corona is continually escaping
•During sunspot maximum: coronal mass ejections
•“space weather”
•Kepler’s 3 Laws
•Orbit of planet is an ellipse with Sun at one focus
•Line joining planet and Sun sweeps out equal areas in equal increments of time
•Planets sidereal period increases with semimajor axis
•I.e velocity of a body in orbit is determined by its distance
•Space station (37 tons, 390 km above ea. Level, 91 min
•Geostationary satellite (35, 786 km altitude, 1 day)
•Moon (385 000 km, 27.3 days)
•Newton’s Laws
•1. Inertia
•2. F=ma
•3. Action = reaction
•Law of gravitation
•2 masses attract one another
•Force = G m M/r^2
•Tides
•Wy do we experience 2 tides per day?
•Exploration of Solar System
•Earth-based telescope vs Hubble (Space telescope)
•Images with false colours
•Satellite remote sensing using radar waves
•Rough terrain reflects more energy, creates bright halos
Monday March 12/12
Introductory Geology
C. Banks
Study Prep
•Landers and rovers
•Humans
•The Inner (‘Terrestrial’) Planets and Their Moons
•Mercury
•Small (.4 RE) and heavily cratered, similar to our moon
•Almost no atmosphere
•80C at night, 460C during day
•Venus
•Similar to Earth in size
•Thick dense CO2 Atmosphere, immense greenhouse effect causing high surface
temperatures (450C)
•Varied terrain (high and low areas)
•Evidence for past volcanic activity (lava flows)
•Mars
•Half the size of earth
•Red colour due to windblown dust
•Olympus Mons, a basaltic shield volcano, is largest in solar system
•Valles Marineris, a 400 km long canyon
•Weathering (channels) and depositional (point bar) structures indicate that water once
flowed there
•Ice caps at poles grow during winter
•Earth and its Moon
•Fall into Sun’s ‘habitable zone’ (i.e., liquid water on planet possible)
•Parameters of Earth’s orbit
•Perihelion and aphelion
•Precession
•Nutation
•Structure of Moon
•Light colored, cratered highlands
•>4 Gyr anorthosite (feldspar rich)
•Low-lying, dark colored ‘maria’
•3.8-2.5 Gyr basalt (filled craters)
•Moon is spiraling away from Earth at 3.8 cm/yr.
•Earth day is getting longer by result
•Energy loss due to tidal friction
•Formation of moon likely by a huge asteroid impact on Earth
•Gas Giants
•Large size, gas rich, all with rings
•Jupiter
•Largest planet (11 Re, 318 Me, >2.5 mass of other planets
Monday March 12/12
Introductory Geology
C. Banks
Study Prep
•‘small’ rocky core
•Only .04 Mj, but 20,000 km diameter, or 13 Me
•Surrounded by liquid metallic hydrogen, normal molecular hydrogen
•Swirling atmosphere
•With narrow bands of rising and sinking clouds and great red spot (25,000 x 12,000
KM > 300 yr. old hurricane
•Rotates once every 10 hours
•5 min slower at poles - banded atmosphere
•Several moons
•Io is so close to Jupiter and its surface experiences 10m high tides and
volcanism
•Ganymede largest moon in the solar system
•Bigger than Mercury
•Europa has icy crust with fissures
•Saturn
•Similar to Jupiter, slightly smaller (9Re)
•Prominent icy rings
•Mimas, one of its moons nearly got blasted apart by an impact of a crater 130 km wide
and 10 km deep
•Uranus
•Terrestrial core, plus layers of liquid water, liquid H+He
•Blue colour (from methane atmosphere)
•Axis of rotation, rings, movement of moon are ecliptic
•Moon Miranda
•236km diameter
•Icy surface with craters and ‘chevrons’ of unknown origin
•Neptune
•Very similar to Uranus
•Moon Triton has two distinct halves
•Asteroids
•Most in belt between Mars and Jupiter
•Most <1km diameter, and odd-shaped
•Several large ones
•Ceres (940 km)
•Pallas (600 km)
•Probably leftover planetsimals
•Small debris scattered throughout solar system may hit earth as meteorites
•Kruiper belt objects
•Beyond orbit of Neptune
•Pluto and Charon (companions) no longer considered a planet and its moon
Monday March 12/12
Introductory Geology
C. Banks
Study Prep