1. Description of…
The Moon

2. Size, Shape, Gravity, Atmosphere
In comparison to Earth:
Smaller – less than width of USA
Smaller density
Almost perfect sphere – slow rotation
1/6 of Earth’s surface gravity
Escape velocity is low (minimum speed to escape the pull of gravity)
Lacks an atmosphere – has an abrupt change at the terminator (line defining dark and light sides)
Not protected from temperature extremes
Lacks oxygen in atmosphere
Note: The moon is non-luminous, but reflects the sun’s light.

3. Craters Greek word “cup” Very small to very large (cm to km)
Rays – bright streaks on surface emanating from craters
Probably formed by meteoroids hitting the surface
Gas explosion from impact makes them bigger than the rock
Some may be formed similar to volcanoes

4. Maria The lunar “seas” Dark areas called “maria”
No liquid water on surface
Hardened lava-filled craters
Roughly circular

5. Mountains and Rills Sometimes named after Earth’s mountain ranges
Up to 5 miles high
Rills = valleys, perhaps formed from lava flows that cover maria