Download Chapter 21, Lesson 2

Chapter 21, Lesson 2
The Inner Planets
Inner Planets – the Terrestrial planets
• Terrestrial Planets – all made of rock and
metal and have solid outer layers
• Differ in:
– Sizes
– Atmospheres
– Surfaces
Mercury
Atmosphere
Because it is
so small,
gravity is not
strong enough
to hold onto
an
atmosphere
Structure
Core: Iron and
nickel
Surface
Moons
Other
Important Info
• Impact
craters
ZERO
Because there
is no
atmosphere:
• Smooth
plains of
lava
• High cliffs
• there is no
erosion
• There is no
wind to
move sun’s
energy
around so
very hot
near
sun/very
cold away
fro sun
Venus
Atmosphere
Structure
Surface
Moons
Other
Important Info
• 97% carbon
dioxide –
causes high
temperatures
due to green
house effect
Rotates so
slowly, period
of revolution is
is shorter than
its period of
rotation (days
are longer than
years)
Solidified lava
ZERO
• Has thick
layer of
clouds that
are made of
acid
Rotates
clockwise
• Hottest
planet in
solar system
due to
greenhouse
effect
What is “greenhouse effect”?
• “occurs when a planet’s atmosphere traps
solar energy and causes the surface
temperature to increase”
Earth
Atmosphere
Structure
• Will support life • Solid inner
core
• Mixture of CO2
surrounded
and water
by liquid
vapor provide
outer core
enough
greenhouse
effect to keep
surface
temperatures
warm enough
Surface
Moons Other
Important Info
Oxygen and silicon one
(is constantly
created and
destroyed because
of the plates
shifting)
Crust is broken
into large
pieces called
“plates”constantly slide
past, away
from or into
each other
(plate
tectonics)
Only planet
with large
bodies of liquid
water
Mars
Atmosphere
Structure
• Carbon
Frozen carbon
dioxide –
dioxide and
much
water
thinner than
Earth’s and
much less
dense
Surface
Moons
Other
Important Info
Iron oxide
(rust)
TWO irregularly
shaped (might
be asteroids
caught in its
gravitational
pull)
• About ½ the
size of Earth