| A | B |
|---|
| Light Year | The distance light travels in one year |
| Galaxy | A collection of stars held together by gravity |
| Rotation | The spining motion of a planet about its axis |
| Revolution | The movment of an object around another object |
| Protostar | The earliest stage of a star's life just before fusion occurs |
| Weight | The relative mass of an object that is affected by gravity |
| Mass | The amount of matter in an object |
| Waxing Phase | Shapes of the moon that are growing toward the full moon |
| Waning Phase | Shapes of the moon that are decreasing toward a new moon |
| Neap Tide | The tide with the least difference between high and low tides |
| Spring Tide | The tide with the greatest difference between high and low tides |
| Red Giant | First stage of a dying star where it expands outward |
| Supernova | The explosion of a dying giant or supergiant star |
| Astronomical Unit | The unit distance from the Sun to the Earth |
| Solar Eclipse | The blocking of sunlight the Earth that occurs when the moon is between the sun and Earth |
| Lunar Eclipse | The blocking of sunlight to the moon that occurs when Earth is directly between the sun and moon. |
| White Dwarf | The remaining hot core of a star after its outer layers have expanded and drifted out into space |
| Black Dwarf | The remaining cooled core of a small to medium star after it has died |
| Neutron Star | A tiny star that remains after a supernova explosion |
| Vernal Equinox | The day of the year that marks the beginning of spring in the northern hemisphere |
| Autumnal Equinox | The day of the year that marks the beginning of fall in the northern hemisphere |
| Summer Solstice | The day of the year when the Sun is directly over head at 23.5 degrees North |
| Winter Solstice | The day of the year when the sun is the lowest in the sky |
| Nebula | A large amount of gas and dust in space where stars are born |
| Gravity | The attractive force between two objects that is responsible for the formation of galaxies, solar systems, tides etc |
| Solar Flare | A geyser like explosion from the surface of the sun |
| Prominence | A loop of gas that protrudes from the sun's surface |
| Corona | The outer layer of the sun's atmosphere that can be seen during a solar eclipse |
| Photosphere | The inner layer of the sun's atmosphere where the light we experience comes from |
| Fusion | The joining of two hydrogen atoms to form one helium atom occuring in the core of the sun |
| Waxing Crescent | The is the first phase right after the new moon |
| Waning Crescent | The phase occurs just before the new moon |
| 1st Quarter | The phase occurs just after the waxing cresent |
| 3rd Quarter | This phase occurs just after the waning gibbous |
| Waxing Gibbous | This phase occurs just just before the full moon |
| Waning Gibbous | This phase occurs just after the full moon |
| Black Hole | The remains of an extremely masive star pulled into a small volume by the force of gravity |
