| A | B |
|---|
| digit | Symbol used to write numbers |
| period | Three-digit group of numbers, seperated from other groups by a comma |
| elliptical | oval-shaped, like a flattened circle |
| model | representation of how something looks or works |
| asteroid | a rocky object that revolves around the sun |
| meteoriod | a small piece of rock and metal that travels in space around the sun |
| meteor | a bright streak of light that passes through Earth's astmosphere |
| light year | the distance light travels in one year |
| constellation | stars that appear to be in groups when viewed from earth |
| galaxy | a group of billions of stars, dust, and gases in space held together by gravity |
| stectroscope | an instrument that searates light into a pattern of lines of different colors |
| refraction | the bending of light as it passes from one material to another; a way to gather and focus light |
| reflection | the bouncing of light off a shiny surface; a way to gather and focus light |
