Origin of the solar system

✸ Origin of the Earth and Solar System- Nebular theory simulation - Concept of stellar evolution - Sun-Earth interactions - Importance of magnetic field - Role of impacts in planet

✸ Origin of the Earth and Solar System

- Nebular theory simulation

- Concept of stellar evolution

- Sun-Earth interactions

- Importance of magnetic field

- Role of impacts in planet fm

✸ Nature of the scientific method

- Homework assignment

- Due FridayToday’s Lecture

Nebular theory: Planets formed at the same time from cloud of dust

& gases called a “nebula”: 80% hydrogen, 15% helium, 5% heavier elements.

Heavy elements sank

to the centers of planets,

forming the cores of

Paintings by William Hartman

Formation of “protoplanets”

by collisional accretion Painting by William Hartman

Inner rocky planets

Outer gas giants

Separated by the asteroid belt

Venus as seen with radar

Venus:

Cloud-covered

Venus by radar

Largest Volcanoes in the Solar System

Largest Canyon System

Martian Meteorite A LH84001: Signs of

Fossil Life- Probably Not!

 Small channel networks located on steep,

poleward-facing, high latitude slopes on Mars, may have been formed by recent outflows of near surface hydrothermal brines, providing potentially habitable environments for a

subsurface biosphere on Mars today.

Liquid Water on Mars?

Mars Exploration Rovers Launch to Mars in June

◆ Big! (2 Earths fit in red spot)

◆ Spins once in 12 hrs

◆ 16 moons

Jupiter’s

moon Io

•Most

volcanically active

object in the Solar System!

Jupiter’s moon Io: Active volcanoes

Europa’s Cracks are Transform Faults!

San Francisco Peninsula

and San Andreas Fault Fault systems on Europa

Saturn’s Moon Titan: Organic haze

& hydrocarbon oceans

◆ Great dark spot

◆ White clouds

◆ 8 known moons

◆ 248 Earth years to go around Sun once

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

◆ A “captured” object

Planets make up ~ 0.15% of the mass of the Solar SystemSun accounts for the other 99.85%!

Heat loss from the Earth’s

Movie of Earth’s interaction with the Sun:

See file SUNSHI~1.MPG

LEGACY OF APOLLO

By going to the moon,

we learned a lot about the early impact history of our planet!

Moon forming impact

Origin of the Moon:

See simulation.file “Origin of the moon1 QT”

Post-Impact Magma Oceans

Painting by William Hartman

EFFECTS OF A 400 KM DIAMETER IMPACTOR

Stable atmosphere and ocean

by ~4.2 billion years ago

Painting by William Hartman

Credit: Des Marais (2000)

Humans arrive

just

a few

seconds before noon.

Hazards of asteroids and comets

Geology

World wide map of known impact structures

Meteor Crater, Arizona

Earth’s internal heat engine.

Sources of heat energy:

Early on- impact Later on- heat of radioactive decay

Magma

Heat loss from the Earth’s interior drives plate tectonics

Plate Tectonics: See Simulation SEAFLO~1.MOV

Are there other Solar Systems with Earth-like planets in our Galaxy?

Nature of scientific inquiry

Process begins with observation and questions This leads to the formulation of hypotheses:

Construction of a tentative (untested) explanations

for things observedBest approach is to formulate multiple working

hypotheses and then try and refute them!

Testing hypotheses means:

Evaluating their explanatory power under a variety of

realistic circumstances

Science progresses most quickly rough the refutation of

hypotheses

Nature of scientific inquiry

Nature of Scientific Proof:

 There is no certainty in science, only

degrees of certainty

 Hypotheses are less certain than

theories

Nature of scientific inquiry

Theory

- well-tested/widely accepted hypothesis that

“acceptably” predicts observed facts

- also: explains additional observations not used

originally to form theory

- predictive power

- still testable and subject to disproof!

Nature of scientific inquiry

Homework Assignment:

1) Identify a major question about the nature or history of the

Earth

2) State two of more alternative hypotheses that attempt to

explain the available observations

3) Design a way to test each hypothesis If you can’t find a way

to test a hypothesis, it probably means it is not very useful, so throw it out and identify another that can be tested

4) If you are using a historical example (e.g shape of the

Earth, continental drift, etc.) from your text, then describe the outcome