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.
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.
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
