20 Planetology07aaa

Geology 12 Planetology: 

Geology 12 Planetology

Unit 5: 

Unit 5 Outline A: Origin of Solar System B: Planets C: Moons

A: Origin of Solar System: 

A: Origin of Solar System

Slide4: 

Big Bang 13.7 billion yrs ago

Slide5: 

0 – 300,000 years: light elements (H2 and He) form (was 100% H2 & He; now 98%) 300 ma: Universe continued expanding forming 1st stars (13.4 ba) and galaxies (Quasars = developing galaxy) Stars produced heavier elements via fusion (Li – Fe) and exploding (super novas)

1st Stars: 

1st Stars

Slide7: 

Nebula

1st Galaxies: 

1st Galaxies

Slide10: 

Solar Nebular Theory: Deals with the creation of solar system 1. Swirling eddy cloud of dust and gas within the galaxy coalesces into a whirlpool.

Slide11: 

2. As the whirlpool spins, it shrinks spinning faster finally into a spinning flat disc.

Slide12: 

3. 90+ % of the mass concentrates at the centre to form an embryonic sun (proto-star) which emits light/heat and solar (hydrogen nuclei) wind

Slide13: 

4. The Sun’s solar wind coupled with all the ionized gasses in the rotating disc caused a magnetic braking effect (Sun now rotates once/25 days) slowing disc down to moderate speeds. Sun Lines of Magnetic force Ionized gasses

Slide14: 

5. Sun’s heat warmed inner disc so lighter elements could not condense so solar wind pushes most of these elements out to form gas giant planets. rocky gaseous frozen Inner Planets Outer planets M V E U S J M N P Hot Cold E C

Solar Nebular Theory: 

Solar Nebular Theory Solar Nebular Theory

Slide19: 

6. <10% of the mass accretes into larger and larger particles which eventually form planetesimals (60 – 100). As the planetesimals collided, they grew in size and mass (gravitational attraction), but fewer in number, to form the planets. Large collisions among planetesimals resulted in: Venus spinning backward very slowly Uranus & Pluto spin on their side

Slide20: 

Two planetisimals colliding

Slide21: 

Orbits

Slide22: 

Orbits

Slide23: 

Asteroids: left over planetesimals Most between Mars and Jupiter (Jupiter’s gravity prevented formation of small planet).

Slide24: 

Now a dwarf planet

Slide25: 

Comets: formed near Uranus and Neptune; the immense gravitational pull of Saturn and Jupiter has created their highly elliptical orbits that range from the Sun to the Oort Cloud at the edge of the Solar System. Sun to Earth = 1 A.U. = dist’ Earth to Sun: 150 m km Sun to Pluto: 39 A.U. Sun to edge of Solar System: 35,000 A.U.

Slide26: 

Comets

Comets: 

Comets

Slide28: 

Oort Cloud Oort Cloud

Slide30: 

Final Result: All planets revolve around the Sun in same direction: CCW (Q.10, p.6) Nearly all planets (‘cept Venus), moons orbit and spin/rotate in same direction: CCW Nearly all axes of rotation are perpendicular to plane of revolution (Plane of the Ecliptic)

Slide31: 

90’ 90’

Slide32: 

4. a) Terrestrial Planets: are small, rocky, high densities (4 – 5.5 gm/cm3) and metallic element (light elements blown…) b) Gaseous Planets: large, low densities (0.7– 1.7 gm/cm3 ) and mostly frozen compounds (cold, little solar wind) 5. Slow rotation of Sun (slowed by magnetic braking) 6. Asteroid belt between Mars and Jupiter (left over pieces of early Solar System)

Slide33: 

Solar System

B: Planets: 

B: Planets Hand out data table on Planets Two Types: Jovian/Gas Giant and Terrestrial

Terrestrial Planets: 

Terrestrial Planets

Terrestrial Planets: 

Terrestrial Planets

Planets: : 

Planets:

Mercury: 

Mercury 4880 km

Slide39: 

1. Mercury Smallest planet (slightly larger than our moon) Closest to Sun (hot on sunny side; cold on shady side + long days: 1 M-day = 58 E-days) Weak gravity and high temperatures caused loss of atmosphere to space Radioactive heat expired long ago causing contraction of planet leading to normal faulting…heavy cratering over faults indicates cooling occurred long ago. (dating via principle of cross-cutting)

Slide40: 

Normal fault

Slide41: 

Mercury: craters & lava flows

Venus: 

Venus

Slide43: 

2. Venus (Earth’s sister/twin planet) because it’s the same size. Shrouded in thick clouds of CO2 and N2. (90x Earth’s pressure) Very hot (+450’C) with runaway greenhouse effect. Active volcanism, folded mountains, faults, trenches indicate tectonic activity. No magnetic field Rotates backwards 1 V-day = 243 E-days

Venus: 

Venus 12100 km

Earth: 

Earth 12800 km

Slide46: 

3. Earth Active volcanism, folded mountains, faults, trenches indicates tectonic activity Plate tectonics, oceans and weathering covers up meteorite impacts

Mars: 

Mars

Slide48: 

4. Mars ½ Earth’s diameter; twice Moon’s Billions of years ago its volcanic outgassing provided ample CO2 and water for oceans. CO2 greenhouse effect warmed Mars so oceans flowed in great seasonal floods cutting immense canyons (and water depositional features). Volcanic activity slowed/ceased long ago (3.5 ba), CO2 atmosphere was lost to space, planet cooled and water froze.

Slide49: 

Now frozen desert with wind storms and dunes. N-hemisphere: large smooth plains, extensive volcanism (Olympus Mons: largest known volcano in Solar System), and few craters. S-hemisphere: heavily cratered from meteorite bombardment (Hellas: 2000 km crater is largest known in Solar System).

Mars: 

Mars 6800 km

Mar’s N-pole: 

Mar’s N-pole

Slide52: 

Mar’s breccia & debris

Slide55: 

Canyon: Valles Mariness

Slide56: 

Olympus Mons

Olympus Mons: 

Olympus Mons

Slide58: 

Face of Mars

Slide59: 

Mars wind storm What kind of dunes are those? Longitudinal dunes

Jovian Planets/Gas Giants: 

Jovian Planets/Gas Giants 3 layer structure: rocky cores, liquid mantle, H2-He (+methane and ammonia) atmosphere topped by clouds All have rings Strong magnetic fields Low density: 0.7 – 2.0 Fast rotators: <17 hrs to a day Many moons

Slide63: 

Jupiter 142800 km

Slide64: 

5. Jupiter Largest planet Liquid mantle of metallic hydrogen creates very strong magnetic field Emits 2.5 x more energy than it receives (heated by compaction-compresson 5 ba ago and is still cooling off). Faint ring + 16 moons

Slide65: 

Rotates very fast -> oblate spheroid: (10hr day)

Slide66: 

Saturn

Slide67: 

6. Saturn BIG rings and 22 moons Emits 2.2 x more energy than it receives Similar structure to Jupiter 10 hr day

Slide69: 

120660 km

Uranus: 

Uranus 50800 km

Slide71: 

7. Uranus 9 faint rings 15 small moons Rotates on its side (was hit by Earth-sized object) which when the magnetic field is measured, gives a precise rotation rate (hard to measure on gaseous planets). Magnetic field Axis of rotation

Slide72: 

Dense rocky core surrounded by deep global ocean of water 17 hr day

Neptune: 

Neptune

Slide74: 

8. Neptune 3 faint rings Very stormy (up to 2000 km/hr winds) despite great distance from Sun??? Rocky core surrounded by slushy water and liquid methane ocean 16 hr day

Slide75: 

48600 km Neptune

Dwarf Planets: 

Dwarf Planets 1 Terrestrial Dwarf Planet: Ceres Rocky, no atmosphere Hi SG: 3-4 2 Ice Dwarf Planets: Pluto & Eris (but up to 50 outer bodies may fit classification) Frozen H2 + He (+methane & ammonia) Periodic faint to no atmosphere Low SG: 2

Ceres: 

Ceres 1000 km diameter (Texas size)

Ceres: 

Ceres

Pluto: 

Pluto 2350 km

Slide80: 

Pluto 2/3 diameter of Moon (2350 km diameter) Highly elliptical orbit crosses Neptune’s Sun Neptune’s orbit 1999 1980

Slide82: 

Eris (formerly called 2003 UB313 and Xena) 2500 km diameter

Slide83: 

Quaoar: one of many (approx’ 50) frozen objects beyond Pluto, some larger than Pluto. 1250km

Terrestrial Planets: 

Terrestrial Planets

All the Planets: 

All the Planets

Sun vs. Planets: 

Sun vs. Planets

Slide87: 

Our Sun vs. Other Stars

Slide88: 

Our Sun vs. Other Even Larger Stars

C: Moons (Natural Satelites): 

C: Moons (Natural Satelites)

Slide91: 

Mercury and Venus: no moons Earth: the Moon Rotates on axis and circles Earth 1/month (27.3 days) Surface has two major parts a) Highlands: light coloured (Fs), oldest (4 ba), heavily cratered b) Maria (sea): dark-coloured basaltic lava flows (3.8 – 3.2 ba ago) Since then nothing but meteorite impacts

Slide92: 

Moon

Slide93: 

Moon Anorthosite Fs 4.5 by Basalt Flows 3.2-3.8 by

Slide95: 

Meteorite Impacts 20 m meteorite traveling @ 10 km/s can excavate a crater 600 m across! 1. Impact and immense heat from pressure and internal friction. That’s only 23,000 mph (36,000 km/h) Shock wave

Slide96: 

2. Compressional rebound ejecta

Slide97: 

3. Result: impact crater ejecta (breccia and dust) Fallback breccia Fractured floor Raised centre Ejecta blanket Top View

Slide98: 

Relative dating: what’s on top is youngest = superposition 3 kinds of material on surface Igneous rocks: basalt (lava flows) Breccia dust + Glass sphericules: result of shock metmorphism Result of meteorite impacts

Slide99: 

Moon Formed from collision with a Mars-sized planetesimal with Earth about 4.5 ba. Molten rock of Moon lost most of its water (only ice is at S-pole believed from an icy meteorite impact) Moonquakes indicate: 100 km crust Plastic and liquid mantle Small solid core

Slide100: 

Moonquakes caused by cooling and shrinking mantle (normal faults)

Slide102: 

Ejecta Blanket Impact Craters

Slide103: 

Impact Craters Raised centre

Slide106: 

Meteor Crater lies at an elevation of about 1740 m (5709 ft) above sea level. It is about 1,200 m (4,000 ft) in diameter, some 170 m deep (570 ft), and is surrounded by a rim that rises 45 m (150 ft) above the surrounding plains. The center of the crater is filled with 210-240 m (700-800 ft) of rubble lying above crater bedrock. The crater was created about 50,000 years ago during the Pleistocene epoch when the local climate on the Colorado Plateau was much cooler and damper. At the time, the area was an open grassland dotted with woodlands inhabited by woolly mammoths, giant ground sloths, and camels. It was uninhabited by humans, the first of whom are thought to have reached North America only around 13,000 years ago. The object which excavated the crater was a nickel-iron meteorite about 50 meters (54 yards) across, which impacted the plain at a speed of several kilometers per second. The speed of the impact has been a subject of some debate. Modelling initially suggested that the meteorite struck at a speed of up to 20 kilometers per second (45,000 mph), but more recent research suggests the impact was substantially slower, at 12.8 kilometers per second (28,600 mph). It is believed that about half of the impactor's 300,000 tonne (330,000 short tons) bulk was vaporized during its descent, before it hit the ground. Berringer Crater, Arizona

Permian Extinction: 

Permian Extinction 80% of species wiped out

Cretaceous Extinction: 

Cretaceous Extinction 50% of species wiped out

Slide113: 

180 km Land Continental Shelf To Can Cun

Slide114: 

3d gravity Anomaly of impact crater

Slide115: 

Mars: 2 small, irregular shaped moons 1. Demos: 8 km long 2. Phobos: 27 km long, circles Mars/8hrs and will crash in 20 ma

Mars Moon: Deimos: 

Mars Moon: Deimos

Mars Moon: Phobos: 

Mars Moon: Phobos

Slide118: 

Jupiters Moons

Slide119: 

Jupiter (18 moons) 4 large moons 1. Io: very close to Jupiter causing huge land tides (+90km) causing tremendous internal friction…this heat leads to intense volcanic activity -> sulphur volcanoes

Slide121: 

Io

Slide122: 

Io

Slide123: 

Io

Slide124: 

“Gravitational tug of war”

Slide125: 

Io

Slide126: 

volcanic plume

Slide127: 

2. Europa: 2nd closest moon Large tides also cause internal friction…enough to melt water…so…Europa has thick oceans of convecting water covered by ice.

Slide128: 

Europa

Slide129: 

Europa ice cracks

Slide130: 

Ice Oceans Solid Rocky Mantle ? Core ?

Slide131: 

3. Ganymede: grooves (ridges and valleys) that are younger than craters suggesting?? Ice crustal plates?? 4. Callistro: most cratered object in Solar System Both largely frozen ice with silicate rocky cores.

Slide132: 

Ganymede Largest moon in SS

Slide133: 

Grooves, ridges of ice?

Slide134: 

Callisto

Slide135: 

Saturn (22 moons) Titan: atmosphere of hydrocarbons and nitrogen; oceans of hydrocarbons ½ rocks and ½ frozen water N2 atmosphere Landed there 2 yrs ago

Slide137: 

Titan 2nd largest moon in SS

Slide138: 

Titan

Slide140: 

Titan’s surface

Slide141: 

Uranus (15 moons) Small Miranda: bizarre V-shaped grooves

Slide142: 

Miranda

Slide143: 

Miranda

Slide144: 

V-groove: Plate Tectonics? Meteorite impact? Shrinkage?

Slide145: 

Neptune (8 moons) Triton Largest moon of Neptune Volcanic activity (geysers of carbon-rich material of N2) Probably a captured planet (same size as Pluto)

Slide146: 

Triton

Slide147: 

Triton

Slide148: 

Triton’s surface

Slide149: 

Nitrogen geyser

Slide150: 

Nitrogen geyser

Slide151: 

Pluto (3 moons) Charon ½ size of Pluto

Slide153: 

Eris: 1 moon called Dysnomia

Do WS 20.1: 

Do WS 20.1