Chapter 9: Planetary Bodies Flashcards
The inner planets are ____ & _____.
The four giant outer planets and their moons are ____, with _____ cores.
Pluto is a snowball of _____, water, & _______
small, rocky
gaseous, rocky
methans, rock
How old is our solar system?
Young! ~4.6 Ga vs. 13+ Ga (universe)
solar system formation is ongoing across universe
Nebular hypothesis
Idea that clouds of gas can form stars and planets
Starting conditions of giant molecular clouds
- Temperature?
- Size?
- Chemistry?
Cold (10-30 K)
Large (10^2 light years across, 10^12 suns across)
98% H and He
- 4% ices
- 4% rock
- 2% metal
Stephs of solar system formation
- Cloud collapse
- Rotating disk
- Condensation
- Accretion
- Gas capture
Most abundant raw materials for planets:
- H, He gases
- “ices” (hydrogram compounds)
- rock and metal
How did the moon form?
A mars-sized body impacted the Earth, propelled debris into space, and the moon aggregated from this debris.
Why is Earth a layered planet?
During gravitational differentiation, iron sank to the center and lighter material floated upward.
Characteristics needed by a planet to have a differentiated surface (2)
Enough gravity to hold gases
Magnetospheric sheath to protect from solar wind (if near sun)
Examples of meteoroid, metor, or meteorite crashes.
Meteor (Barringer) Crater, AZ
Upheaval Dome, UT
Clearwater Lakes, Quebec
Crater counting can give us…
Age
Terrestrial Planets
Earth (mostly iron, oxygen, and silica)
Mercury
Venus
Mars
Requirements to be a planet:
- Orbits the sun
- Large enough to have become round due to force of own gravity
- Is not a satellite (orbit another planet)
- Must dominate the neighborhood around its orbit
Dwarf planets only martch the first 3 criteria.
