These are the most frequently used words in this book.
although
amount
areas
atmosphere
atmospheric
between
bodies
carbon
changes
climate
cloud
co2
cold
comets
composition
craters
credit
deposits
different
during
dust
early
earth
enough
europa
even
features
few
fig
figure
form
formation
formed
ganymede
gas
gases
ground
heat
high
however
hydrogen
ice
icy
images
impact
interior
jupiter
kilometers
large
layer
less
mars
martian
mass
material
may
mercury
meters
methane
molecules
moon
near
neptune
nitrogen
objects
ocean
orbit
outer
period
planet
pluto
polar
poles
present
pressure
process
radar
regions
result
rocks
satellites
sheet
similar
size
small
snow
solar
source
space
spacecraft
sun
surface
system
temperature
time
triton
two
volatile
water
years