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Astronomy terms
A list of terms from apihelion to comets
Term | Definition |
---|---|
Astronomy | The study of creation beyond our atmosphere. |
Perihelion | Earth's closest point to the sun. |
Aphelion | Earth's farthest point from the sun. |
Period | The amount of time a planet takes to complete its orbit. |
Astronomical unit | A measure used by Kepler equal to the earth's distance from the sun. |
Vacuum | A space containing no matter. |
Retrograde | Moving backwards (from east to west). |
Mare | Dark patches on the surface of the moon. |
Satellite | Any object which revolves around another object. |
Lunar month | The amount of time it takes the moon to revolve around earth (29d 12h 44m). |
Asteroid | A stony or metal object smaller than planets and orbiting the sun. |
Comet | An asteroid sized object made of rock and frozen material and forms a bright tail. |
Nucleus | The heart of a comet made of two-thirds ice and one-third dust. |
Coma | The gas and dust forming around a comets nucleus. |
Tail | A highly reflective streamer emitted from a comet. |
Meteoroid | Fragments from asteroids much smaller than them. |
Meteor | A meteoroid that has entered the earth's atmosphere. |
Meteor shower | An event that takes place when the earth passes through a meteoroid stream causing meteor to fall much faster than normal. |
Meteorite | A meteor that has crashed to the earth's surface. |