Glossary Words
Alvarez
aphelion
asteroid
asteroid belt
astronomer
astronomical units(AU)
carbon dioxide
coma
comet
DNA
dust tail
ellipse
extinction
extraterrestrial
extrinsic catastrophist
giant planets
Giotto spacecraft
graphite
hypothesis
intrinsic gradualist
invertebrate
iridium
Jan Van Oort
kilometer
Kuiper belt
light year
long period comet
mantle
meteor
meteoroid
meteor shower
meteorite
nucleus
oblique angle
Oort Cloud
orbit
organic matter
perihelion
period
planetesimals
plasma
plasma tail
plate tectonics
revolve
short period comet
solar nebula
solar system
solar wind
sublimate
vertebrate
volcanism
Fred L. Whipple