1. Connecting Planetary Interiors and Surfaces
Shaping Planetary Surfaces

2. Planetary surfaces share some similar features, but not all.
Examples of geological surface features:
Erosional features
Volcanoes and lava flows
Rift valleys
Impact craters
Uplifted mountains

3. Terrestrial planet interiors have similar layers
All terrestrial planet interiors underwent “differentiation”

4. How do we know what’s inside the Earth? Have we been there?

5. How do we know what’s inside the Earth? Have we been there?
NO! Seismic waves are our probes of the Earth’s interior
Seismic waves
The waves bend as they move through changing densities
P waves can penetrate the liquid outer core
P waves: “primary”, “pressure”, or “push-pull”
S waves can’t
S waves: “secondary”, “shear”, or “side-to-side”
This science is called “seismology”

6. Which is the densest layer of the Earth’s interior?
A) Crust
B) Lithosphere
C) Mantle
D) Liquid core
E) Solid core

7. Which type of seismic wave can penetrate the liquid part of the core?
A) P-waves
B) S-waves
C) They both can
D) Neither

8. What drives geological activity? HEAT
So where does the heat come from?
Accretion
Impacts bring kinetic energy
Differentiation
Gravitational potential energy is released as denser material sinks
Radioactive decay
Still heating the Earth’s interior today

9. How do planets lose that heat?
When a planet has lost too much heat, it loses its geological activity:
Volcanoes
Plate tectonics
Earthquakes
Large planets stay warm longer:
More heat to begin with
Smaller surface area to volume ratio
3 ways:
Radiation
Conduction
Convection
Note that convection can carry heat all the way out through the crust in the form of volcanoes

10. Magnetic Fields All magnetic fields are created by moving charges
Bar magnet –
field created by orbiting electrons
Electromagnet –
field created by electrical current
Earth’s magnetic field –
created by convection in molten core and Earth’s rotation
 Magnetic field also depends on internal heat

11. Shaping planetary surfaces
Water erosion
Shaping planetary surfaces
Volcanism
Glacial erosion
Plate tectonics
Wind erosion
Impact cratering

12. Impact Cratering See these for yourself Saturday night
Typical features in larger craters:
Central peak (rebound)
Terraced walls
The explosion is caused by energy released (vaporizing the rock), like a bomb going off
The underlying crust is fractured
Ejecta is thrown out and may create “secondary craters…”
These features erode over time
See these for yourself Saturday night
7 – 9 p.m. at the observatory

13. Secondary
Craters
(and rays)
Ejecta
“blanket”

14. Only relatively young craters retain those features
Theophilus
Madler
Mare Nectaris
Cyrillus
Rosse
Catharina
Fracastorius

15. Rank the craters, oldest to youngest.
A) Ptolemy, Alphonsus, Arzachel
B) Ptolemy, Arzachel, Alphonsus
C) Arzachel, Alphonsus, Ptolemy
D) Arzachel, Ptolemy, Alphonsus
E) Alphonsus, Ptolemy, Arzachel
Ptolemy
Alphonsus
Arzachel

16. Silica content determines viscosity
Volcanism
Silica content determines viscosity
Low viscosity
Maria
Medium viscosity
Shield volcanoes
High viscosity
Stratovolcanoes

17. Plate movement is driven by convection in the mantle
Plate tectonics
Crust
Plate movement is driven by convection in the mantle

18. Plate tectonics Oceanic crust: Denser, sinks below continental crust
Continental crust: Less dense, rides above oceanic crust
Mid-ocean ridge: New crust is forming here
Subduction: Where oceanic crust sinks below continental crust
Rift zone: Where continental plate is being pulled apart

19. Sedimentary rock is the most common type on Earth’s surface
Erosion
V-shaped
U-shaped
Sedimentary rock is the most common type on Earth’s surface

20. Erosion creates oxbow lakes

21. Which process formed the geological feature shown?
A) Impact cratering
B) Water erosion
C) Volcanism
D) Tectonics
E) Glacial erosion

22. True or False:
There is no erosion on the surface of the Moon, so Neil Armstrong’s footprints will be there forever.
A) True
B) False

23. You can tell the relative age of surfaces by looking at the number of impact craters
Few craters = relatively young
(3.0 – 3.9 billion years)
Lots of craters = relatively old
(4.4 billion years)

27. Astro-Cash Cab!
Samantha
Hunter
Crystal
Zach
Jack

28. 1) Which seismic waves travel faster?
P waves
S waves
They travel at the same speed

29. Lunar maria were formed from high viscosity lava.
2) True or False?
Lunar maria were formed from high viscosity lava.

30. 3) Which surface-shaping geological process requires an atmosphere?

31. It depends on distance from the Sun, not size
4) Which terrestrial planet is more likely to have a strong magnetic field?
Small planet
Large planet
It depends on distance from the Sun, not size