Terrestrial Planets
(Chapter 17)
Student Learning Objectives
• Identify & describe each Terrestrial Planet
• Compare & contrast the Terrestrial planets
with our Earth
What are the main characteristics
of Terrestrial planets?
Small
Metals
High density
(iron & silicates)
Rocky Objects
Solid surfaces
Differentiated
Surfaces
Four processes alter solid surfaces.
1. Impact craters
2. Volcanoes (flood impact craters)
3. Plate tectonics
4. Weather
Many craters  Old surface
Few craters  Young surface
Daedalus Crater (taken by the Apollo 11 crew)
Practice
Which surface is relatively older?
B
A
What are some features of Mercury?
Mercury has a 2/3
resonance with the Sun.
2 Rotations
3 Revolutions
2/5 Size of Earth
−290 °F to +800 °F
Mercury is almost all core.
0 Moons for Mercury
Practice
1) Why does Mercury have such a large
temperature range (−290 °F to +800 °F)?
2) What could explain the structure of Mercury
(that it is mostly core)?
More Practice
3) Is Mercury more similar to our Moon or the
Earth?
4) Is the surface of Mercury young or old?
5) Why do we see little evidence of impact
craters on our Earth?
How do Venus and Mars compare to Earth?
Thick atmosphere
 96% CO2
 Atmospheric pressure 90x
greater than Earth’s
 Complete cloud cover
(sulfuric acid droplets)
Venus
9/10 Size of Earth
Always +900 °F
0 Moons
The North Pole of Venus
APOD
Practice
1) Why is the temperature on Venus constant?
2) Venus spins retrograde. Why?
More Practice
3) Is Venus more similar to our moon or the
Earth?
4) Is the surface of Venus young or old?
5) Earth has a surface feature that dissolves CO2.
What is it?
Seasons similar to
Earth’s seasons
Thin atmosphere
 95 % CO2
 Atmospheric pressure
1% of Earth’s
Mars
2 Moons for Planet Mars
1/3 Size of Earth
−220 °F to +70 °F
Frozen polar caps
CO2 & H2O
Northern Polar Ice Cap of Mars
NASA
Practice
1) What would cause Mars to have seasons
similar to Earth’s seasons?
2) Mars has an atmosphere dominated by CO2,
but it does not have a greenhouse effect.
Why?
More Practice
3) Is Mars more similar to our moon or the
Earth?
4) Is the surface of Mars young or old?
5) What is the name of the current NASA rover
exploring on Mars?