1. Introduction

2. Observations: initial knowledge about

the Solar System

3. Explaining the observations

4. Consequences for the Earth

5. The scientific method revisited

FORMATION OF EARTH AND

THE SOLAR SYSTEM

The Solar System- not to scale!

Sun Mercury

Venus Earth

Mars

Jupiter Saturn Uranus

Neptune

Pluto

The Solar System. Source: Christopherson, 2012, p. 41.

Pieces of the Allende meteorite. Source: Smithsonian Institution.

A chunk of Acasta gneiss, from northern Canada.

Source: Smithsonian Institution.

The Allende meteorite has been dated

radiometrically at about 4.6 billion years old.

The Acasta gneiss is the oldest rock yet found

on Earth, dated radiometrically at about 4.0

billion years old.

Thus, the Solar System is around 4.6 billion

years old, and the Earth formed somewhere

between 4.0 and 4.6 billion years ago.

The Solar System. Source: Christopherson, 2012, p. 41.

Planets all orbit the Sun in the same direction.

The inner Solar System. Source: Christopherson, 2012, p. 41.

Each planet rotates on its axis

in the same direction, except

for Venus and Uranus.

The Solar System- not to scale!

Rocky/terrestrial/inner planets:

Mercury, Venus, Earth, Mars

Gaseous/giant/outer planets:

Jupiter, Saturn, Uranus, Neptune

COMPOSITION OF ROCKY

vs. GASEOUS PLANETS

Rocky planets are ~90% iron, silicon, oxygen and

magnesium (Fe, Si, O and Mg)

Gaseous planets are mostly hydrogen, helium,

methane and ammonia (H, He, CH4, NH3)

SOLAR SYSTEM CHARACTERISTICS

1. Sun contains 99.9% of mass of solar system

2. Planets orbit the Sun in the same direction

3. Most planets rotate on their axes in the same

direction (Venus and Uranus are exceptions)

4. Orbits are elliptical, not circular, and lie roughly on

the same plane (the plane of the ecliptic)

5. Planets are roughly twice as far from the Sun as the

next planet in

6. Planets form two distinct groups- rocky vs. gaseous

Mercury The Moon

Mars

Meteor Crater, Arizona (Earth)

SO WHAT??

Consequences of Solar System’s

formation for the Earth

Consequences of Solar System’s

formation for the Earth

1. COMPOSITION

2. CHEMICAL DIFFERENTIATION

4. ORBITAL CHARACTERISTICS

Earth is >90% Fe, Si, O, Mg

Differences in crust vs. whole Earth (layers)

3. EARLY ATMOSPHERE

IRON

35%

IRON 6%

OXYGEN

30%

OXYGEN

46%

SILICON

15% SILICON

28%

MAGNESIUM

13%

MAGNESIUM

4%

ALUMINIUM 8%

NICKEL

2.4%

Consequences of Solar System’s

formation for the Earth

1. COMPOSITION

2. CHEMICAL DIFFERENTIATION

4. ORBITAL CHARACTERISTICS

Earth is >90% Fe, Si, O, Mg

Differences in crust vs. whole Earth (layers)

3. EARLY ATMOSPHERE Volcanic outgassing of CO2, CH4, etc.

Irregular- elliptical, tilt, wobble

Source: California and Carnegie Planet Search, www.exoplanets.org

Geographic location

• Latitude

• Longitude

Latitude. Source: Christopherson, 2012, p. 16.

Latitude. Source: Christopherson, 2012, p. 16.

Latitudinal zones. Source: Christopherson, 2012, p. 16.

Longitude. Source: Christopherson, 2012, p. 17.

Longitude. Source: Christopherson, 2012, p. 17.