| A | B |
|---|
| solar eclipse | occurs when the Moon blocks the Sun's light |
| equinox | the time of year when day and night are the same length |
| astrolabe | a star map drawn on a metal plate |
| sextant | measures the angle between the horizon and a point in the sky |
| radio telescopes | dishes that collect and focus radio waves |
| telescopes | collect and concentrate light |
| patterns | seasons, phases of the Moon, and the rising and setting of the Sun |
| Isaac newton | developed a reflecting telescope that showed objects in sharper detail |
| Galileo | descovered that the planets revolved around the sun |
| light year | the distance light travels in one year |
| nebula | a cloud of gas and dust in which new stars form |
| supernova | a gigantic explosion of a star millions or billions of times brighter than the star was |
| black hole | where the gravity is so strong everything gets sucked in |
| Sun | the closest star to Earth |
| red stars | coolest stars |
| white stars | hottest stars |
| layers of the Sun | photosphere, chromosphere, corona |
| constellation | huge system of stars, dust, and gas |
| galaxy | an area of the sky and all the stars visible in that area |
| Milky Way | galaxy |
| Ursa Major | constellation |
| spiral galaxy | bright center and wispy arms fanning out from the center |
| elliptical galaxy | football shaped galaxy |
| Northern Hemisphere | half of the Earth north of the equator |
| Southern Hemisphere | half of the Earth south of the equator |
