Download Observations about our Solar System 1. planets, moons, asteroids

Science is built of facts the way a house is
built of bricks, but an accumulation of facts
is no more science than a pile of bricks is a
house.
- Henri Poincare’
Creation and development of the Earth
Webpage for course (daytime)
Webpage for course (nighttime)
Lecture 3
Observations about our Solar System
1. planets, moons, asteroids form ring @ sun
2. all these revolve in same direction
3. most have similar orientations
4. most rotate in same direction, as does sun
5. many moons have same general features
6. distribution of planets
Terrestrial vs. Jovian
Nebula Hypothesis
Nebula Hypothesis
Earliest structure of the earth
unsorted mix of compacted gas and
dust?
How did earth become molten?
Sources of heat
- impact of meteorites
- compression
- radioactive decay
This history explains
Thin crust
Differentiation of earth by density
heavy material in middle of earth (core)
lighter material in crust
intermediate density in mantle
Formation of atmosphere
convection cells in mantle
Thin crust and convection cells in mantle
help account for
- plate tectonics (continental drift)
- mountains
- erosion and deposition
Our earth is a very active planet
Nature’s Law is change; constancy is strange.