| A | B |
|---|
| Aphelion | point in orbit where object is farthest from the sun |
| asteroid | large rock or metal that orbits the sun within the asteroid belt |
| astronomical unit (AU) | the unit of measure in space. Distance from the Earth to the sun |
| comet | lump of ice, frozen gas, and dust that orbits the sun |
| eclipse | when one body in space cast a shadow over another |
| ellipse | flattened circle; shape of an orbit |
| equinox | (fall and spring) equal hours of dark and light |
| light year | a unit of measurement approximately equal to 10 trillion kilometers |
| meteors | rocks or metal that enters the Earth's atmosphere |
| moon phases | changes on the moon's appearance due to the shadow of the earth |
| nebula | a spinning cloud of dust in space |
| orbit | a curved path around a planet or star |
| periphelion | point in orbit where object is closest to the sun |
| planets | large bodies that robit a star (8) |
| revolution | 1 complete orbit (Earth takes 365 1/4 days) |
| rotation | spinning of a planet on its' axis (EArth takes 24 hrs) |
| solar system | the sun and all the objects that orbit around it |
| solstice | point in the Earth's orbit where the North pole is pointed directly toward the sun or directly away from the sun (summer and winter) |
| tides | movement of the ocean due to the gravity of the moon |
| waning | to shrink in size |
| waxing | to grow in size |
| satellite | an object that is in orbit |
