                    Moon ABCs Fact Sheet
  Property           Earth                     Moon                          Brain Busters
Core          Iron, nickel metal Same, but core is        What portion of each body is
                                 much smaller             core?
Sediment or   Silicon and        Silicon and oxygen       Do you think life ever existed
Regolith      oxygen bound in bound in minerals,          on the Moon?
              minerals that      glass produced by        Why or why not?
              contain water,     meteorite impacts,
              plus organic       small amounts of
              materials.         gases (e.g., hydrogen)
                                 implanted by the solar
                                 wind. No water or
                                 organic materials.
Atmosphere    78 % nitrogen,     Basically none. Some Could you breathe the lunar
(main         21 % oxygen        carbon gases (CO2 , atmosphere?
constituents)                    CO, and methane),
                                 but very little of them.
                                 Pressure is about one-
                                 trillionth of Earth's
                                 atmospheric pressure.
Length of day 23.93 hours        27.3 Earth days          How long does daylight last
 (sidereal                                                on the Moon?
  rotation
  period)
Surface       Air temperature    Surface temperature Why are the temperatures of
temperature   ranges from        ranges from -193oC Earth and the Moon so
              -88oC (winter in   (night in polar          different?
              polar regions) to   regions) to 111 Co
                 o
              58 C (summer in (day in equatorial
              tropical regions). regions).

Surface         25 % land           84 % heavily-cratered Compare maps of Earth and
features        (seven continents) highlands.             the Moon. Is there any
                with varied terrain 16 % basalt-covered evidence that plate tectonics
                of mountains,       maria.                operated on the Moon?
                plains, river val-  Impact craters--
                leys. Ocean floor some with bright rays,
                characterized by crater chains, and
                mountains, plains. rilles.

18                           Exploring the Moon -- A Teacher's Guide with Activities, NASA EG-1997-10-116-HQ
