Introduction toIntroduction toPlanetary GeologyPlanetary Geology

Patricio FigueredoPSF 571

figueredo@asu.edu

Patricio FigueredoPSF 571

figueredo@asu.edu

Planetary geology

Magellan

GalileoMGS

Odyssey

MER roversMars Express

1) the Solar System1) the Solar SystemPlanetaryPlanetaryGeologyGeology

Planets make up ~ 0.15% of our Solar System’s massSun accounts for the other 99.85%!

The Solar System of Planets

Overview of PlanetsOverview of PlanetsPlanetaryPlanetaryGeologyGeology

The planets’ composition changes with distance to the Sun

Ven

us

Mer

cury

Ear

thM

ars

Jupi

ter

Sat

urn

Ura

nus

Nep

tune

Plu

to

Su

n

terrestrialplanets(mostly rock & metallic)

Gas Giant planets (H, He)w/ rock/ice satellites

Satellites are worlds in their own right!

Mercury

No atmosphere, lots of craters Looks like our Moon Mercury day takes 6 months! only half of it is known

Venus

Earth-like size, density covered in thick clouds surface very hot 900 oF! recent volcanism and tectonics

Earth-like size, density covered in thick clouds surface very hot 900 oF! recent volcanism and tectonics

Earth

GEOLOGIC PROCESSES:•tectonism •volcanism•gradation•impact cratering

tectonism volcanism

gradation

Impacts!!!

mess cars

cause extinctions

knock trees

scar planets!

Impact craters on Earth

PlanetaryPlanetaryGeologyGeology

Meteor Crater, AZ

Impact origin of the Moon!

the Moonthe MoonPlanetaryPlanetaryGeologyGeology

Unusual….Moon is large for a planet “moon”

Its density is ~ 3.3 gm/cm3… This is close to Earth crustal rocks

Gravity on Moon is 1/6 that on Earth

the Moonthe MoonPlanetaryPlanetaryGeologyGeology

mariamaria

highlandshighlandsmaria - large basalt flows

highlands - cratered old crustregolith - unconsolidated rock & dust layer

Mars

•half Earth’s size•two small moons•canyons, volcanoes, etc.

Canyons!

Volcanoes!

•huge shield volcanoes•flood plains

Mars water!!

ASU discovery: Marsgullies’ smoking gun

on the news: The Mars Exploration rovers

Last Saturday: Opportunity landed!

Jupiter

Largest planet in the Solar system

giant storm systems

(2 Earths fit in red spot)

62 moons!!!

Io

Europa

GanymedeCallisto

Geologic targets

Io

Volcanically active!

8 or more volcanoeserupting at anygiven time

Europa

ocean of salty water under the ice! (~2 Earth oceans!!)

composition similar to Jupiter, but twice as far from Sun Most extensive ring system Atmosphere winds: 930 m.p.h.! At least 21 moons

Saturn

Titan

•only satellite with atmosphere!

•organic (C) compounds

•lakes of liquid methane, H

Cassini (07/04)

Uranus Methane atmosphere (blue)

Rotates on its side

At least 15 moons

Miranda

•unique terrain!!

•huge extensional systems

•16 km cliff!!

Neptune

Also methane atmosphere

Great dark spot and White clouds

8 known moons

Triton

•cantaloupe terrain

•fissures, pools

•active giant geyser eruptions!!

Pluto / Charon

binary system

248 Earth years to go around Sun once

Charon, its moon, is over half Pluto’s size

only unexplored planet

Some key points

• 4 geologic processes: tectonism, volcanism, gradation,

impacts

• Mercury resembles our Moon, and is inactive

• Venus has thick atmosp., high T, and recent volcanism and

tectonics

• Earth is an active planet, driven by plate tectonics

• Mars has huge volcanoes and canyons. Water was stable in

the past.

• Jupiter’s Io is the most volcanic body in the Solar System

• Jupiter’s Europa is prob. active, could have an ocean of salty

water

• Saturn’s Titan has a thick atmosphere and organic

compounds

• Uranus’ Miranda has enormous extensional faults and cliffs

• Neptune’s Triton has active geysers

• Pluto and Charon form a double-system and remain

unexplored

• Apart from Earth, only Mars, Europa, Titan, and prob. Triton have some potential for astrobiology