UNIVERSITY OF SOUTH ALABAMA
GY 112: Earth History
Lecture 2: Origins Part 2:
The Earth-Moon System
Instructor: Dr. Douglas W. Haywick
Last Time...
1. Contact info for D. Haywick
2. GY 112 Course Outline (syllabus)
3. Surviving GY 112 (website)
4. Origins 1: The Universe
Origins: The Universe
Photo credit WMAP Science team, NASA
How did it all begin? (and when)
Using the red shift of galaxies as well as other
astronomical techniques (e.g., distribution of microwave
radiation), scientists have now “agreed” to a date for the
age of the universe….
13,700,000,000 Years
How did it all begin? (and when)
Enter gravity….
Source: www.mbscientific.com/BigBang.jpg
What about stars?
Enter fusion….
Source: physics.uwyo.edu/~stark/outreach/StarLives/life+death/fusion.gif
Supernova 1987a –
15 years later
Astronomy picture of the day (http://antwrp.gsfc.nasa.gov/apod)
Today’s Agenda
1. Formation of the solar system
2. Formation and differentiation of the Earth
(Hot and Cold Accretion)
3. Formation of the moon (4 hypotheses)
(Web Lecture 2)
The Eagle Nebula
Astronomy picture of the day (http://antwrp.gsfc.nasa.gov/apod)
Formation of the
solar system >5GA
Chalk board time
The Sun
Hydrogen-alpha filter
Astronomy picture of the day (http://antwrp.gsfc.nasa.gov/apod)
Unknown filter
The Sun
•A rather small and ordinary
yellow star
•Formed 4.6+ billion years ago
•Should “burn” another 5 billion
years
•Will eventually “fade” away
rather than explode
Astronomy picture of the day (http://antwrp.gsfc.nasa.gov/apod)
The Solar System
Source: http://www.solarviews.com/eng/solarsys.htm
The Solar System (to scale)
Source: http://www.solarviews.com/eng/solarsys.htm
The Earth
Age: 4.6 Ga
Composition: rock/metal
Planet Diameter: 12,756 km
Mass: 6x1024 kg
Distance from Sun: 150
million km
Astronomy picture of the day (http://antwrp.gsfc.nasa.gov/apod)
The Earth
One of several planetary
bodies in the solar system that
is tectonically active.
Source: http://www.solarviews.com/cap/earth/earthfg2.htm
An early Earth?
Planetary accretion models
suggest that planets grow larger
as more and more planetoids
lump together. Some models
suggest this was a hot process.
Others suggest it was cold.
Hot Accretion vs Cold Accretion
Miranda; a moon of Uranus
Chalk board time
Astronomy picture of the day (http://antwrp.gsfc.nasa.gov/apod)
The Earth-Moon System
We are more of a binary planetary
system than a planet with a moon
A photograph from Mars!
The Earth-Moon System
How did (and when) the
moon form?
A photograph from Mars!
Astronomy picture of the day (http://antwrp.gsfc.nasa.gov/apod)
The Earth-Moon System
4 Moon Formation Hypotheses:
1) Fission
2) Capture
3) Double Planet
4) “Glancing Blow”
Chalk board time
Astronomy picture of the day (http://antwrp.gsfc.nasa.gov/apod)
Origin of the EarthMoon System
“Glancing blow” impact
sometime before 4.1 GA
Most likely time interval: 200
MA after formation of the Earth
Source: http://spaceflightnow.com/news/n0108/15mooncreate/
Today’s Homework
1. Download and read web notes 1 & 2
2. Organize your notes
3. Decide on Option 1 or 2
Next Time
1) Select your preferred assessment option
2) Lecture: Geological thinking (4)
GY 112: Earth History
Lecture 2: Origins Part 2
Instructor: Dr. Doug Haywick
dhaywick@southalabama.edu
This is a free open access lecture, but not for commercial purposes.
For personal use only.