| Term |
Meaning |
| Rotation | The spinning of a planet or other object on its axis. |
| Revolution | the orbiting of a planet or other object around the sun or another central body. |
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| Star Clusters | A group of stars held together by their mutual gravitational attraction that formed together at about the same time. |
| Spectra | Colors of the rainbow. that appear |
| Galaxy | any of the very large groups of stars and associated matter that are found throughout the universe |
| Recession | retrograde movment (moving backward) |
| Apogee | The farthest point from Earth reached by the moon or an orbiting artificial satalite. |
| Perigee | The point in its orbit where the Moon, or planet is closest to the Earth.
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| Asteroid | a small, rocky chunk of matter orbiting the sun, also called a minor planet, most asteroids orbit in the asteroid belt |
| Asteriod belt | a band between mars and jupiter where most asteroids orbit |
| Barycenter | The center of mass in a system of two orbiting bodies |
| Celestial sphere | a huge, imaginary sphere around the Earth, used to model the positions and motions of celestial bodied |
| Comet | mass of frozen gases revolving around the sun, generally in a highly eccentric orbit |
| Eclipse | the darkening of a celestial body as it passes through the shadow of another body, the obscuration of all or part of the sun by a celestial body |
| Equinox | the time when the sun crosses the plane of the earth’s equator making night and day of approximately equal length all over the world |
| Gibbous moon | a phase between quarter and full that shows a surface that is more than half illuminated |
| Lunar eclipse | an eclipse in which parts of the Moon are darkened be the Earth’s shadow, lunar eclipses occur at times of the full moon |
| Meteor | the luminous trail of heated air produced by a meteoroids passage through the earth’s atmosphere |
| Meteorite | a meteoroid that reaches the surface of the Earth or another planet or moon |
| Meteor shower | an event caused by the earths passage through the orbit of a comet, where it will collide with an increased number of meteoroids, it happens at the same point in the Earth’s orbit and thus on the same date every year |
| Partial Lunar eclipse | an eclipse in which only part of the moon enters the umbra and is darkened |
| Penumbra | the light shadow outside the dark shadow of an opaque body, where the light from the source of illumination is partially cut off |
| Solar corona | a faint halo of gases surrounding the sun visible during a total solar eclipse |
| Umbra | the dark shadow of an opaque body, here direct light from the source of illuminations completely cut off |
| Waxing moon | any phase during with the illumination fraction of the face increases |
| Zenith | the point in the sky directly above the observer, opposite the nadir |
| Nadir | the point in the celestial sphere directly beneath the observer, opposite the zenith |
