| A | B |
|---|
| Big Bang | Hypothesized explosion that created the universe. |
| Nebulae | Huge clouds of hydrogen and helium |
| Sun | Has an atmosphere composed of a photosphere, chromosphere and corona |
| Parsec | Distance to a star with a parallax angle of 1 arc second |
| Hubble's Law | Used to calculate the distance from Earth to a distant galaxy |
| Quasar | Bright centers of distant, young galaxies; emits large amounts of long wave radiation |
| Solar wind | Stream of electrically charged particles |
| Sunspots | Areas of gas in the photosphere that are cooler than surrounding gases |
| Prominences | Huge loops of gas that erupt from sunspot regions |
| Light year | About 9.5 trillion kilometers |
| Parallax | Apparent change in position of an object with respect to a distant background |
