What to Know:

• What are the four inner planets?

• What are the four outer planets?

• What are the major differences between the inner and outer planets?

• What are the three different types of galaxies?

• What is the order of the planets, from the Sun to the Kuiper belt?

Definitions - The Sun, Revolution, rotation, equinox, solstice, waxing, waning, tide, solar eclipse, lunar eclipse, crescent moon, gibbous moon, planet, dwarf planet, moon, asteroid, comet, meteoroid, meteor, meteorite, star, light-year, galaxy, Asteroid belt, Kuiper belt, Oort cloud, Big Bang Theory, singularity.