These are the most frequently used words in this book.
across
although
another
appears
area
away
between
bright
camera
central
clearly
close
computer
crater
dark
days
described
detail
diameter
digital
during
earth
even
features
figure
first
floor
following
formed
full
good
great
having
high
however
illuminated
image
jupiter
km
large
largest
later
lava
lies
light
little
low
lunar
mare
may
meters
million
moon
mountains
must
night
north
now
orbit
peak
photograph
pictures
place
plain
planets
rays
region
ridges
right
ring
saturn
second
see
seen
shadow
show
shown
size
sky
small
smaller
solar
south
spot
sun
surface
system
take
taken
techniques
telescope
terminator
time
tiny
towards
two
view
visible
walls
years