| A | B |
|---|
| solar system | includes the Sun and its family of orbiting planets, moons, and other objects |
| galaxy | millions or billions of stars held together in a group by their own gravity |
| universe | space and all the matter and energy in it |
| ellipse | an oval or flattened circle, the shape of an orbit |
| rotation | the motion of a body on its axis, the cause of day and night |
| revolution | the motion of one body around another due to gravity |
| seasons | yearly patterns of temperature changes and weather trends caused by Earth's tilted axis and orbit around the Sun |
| eclipse | where one object in space casts a shadow onto another |
| waxing | the part of the lunar cycle where the Moon appears to grow |
| waning | the part of the lunar cycle where the Moon appears to shrink |
| comet | a small icy body that orbits the Sun and produces a coma and tail of gas and dust |
| asteroid belt | a group of small, solid, rocky bodies that orbit the Sun between the inner and outer planets |
| meteor | a brief streak of light produced by a small particle entering Earth's atmosphere at a high speed |
| meteorite | a small object from outer space that passes through Earth's atmosphere and reaches the surface |
