30 terms

Astronomy 2

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Ellipse
A closed, symmetric curve shaped like an oval or circle having two foci.
Foci
The two points needed to draw an ellipse.
Gravity
The force of attraction between two masses.
Impact Crater
A depression in the ground caused by a meteorite or other object hitting the Earth's surface.
Orbit
The curved path of a celestial object around another celestial object.
Revolution
The orbiting of one celestial object around another.
Rotation
The spinning of an object on its axis.
Apparent Motion
Perceived movement caused by the viewer's position moving not the object. It appears to be moving but it's not.
Eclipse
The partial or total blocking of one object in space by another.
Phases
One of the different apparent shapes of the moon or a planet as seen from Earth.
Tide
The daily changes in the elevation of the ocean surface.
Spring Tide
A tide just after a new or full moon, when there is the greatest difference between high and low water.
Neap Tide
A tide just after the first or third quarters of the moon when there is the least difference between high and low water.
Perigee
The point in the orbit of the moon at which it is nearest to the earth.
Apogee
The point in the orbit of the moon at which it is furthest from the earth.
Waxing Moon
The moon at any time after new moon and before full moon, where the light is increasing and the right side of the moon.
Waning Moon
The moon at any time after full moon and before new moon, where the light is decreasing and the left side of the moon.
Gibbous
When the observable illuminated part of the moon greater than a semicircle and less than a circle.
Solar Eclipse
An eclipse in which the sun is obscured by the moon.
Lunar Eclipse
An eclipse in which the moon appears darkened and has a reddish color as it passes into the earth's shadow.
Cyclic
Occurring in cycles; regularly repeated and predictable.
Synodic Month
A lunar month that contains all of the phases of the moon. Lasts 29.5 Days.
Sidereal Month
The REAl amount of time for a revolution of the moon around the earth. Lasts 27.3 Days
New Moon
The moon phase where none of the moon is illuminated.
Full Moon
The moon phase where 100% of the moon is illuminated.
First Quarter
The moon phase where 50% of the moon is illuminated on the right side.
Third/Last Quarter
The moon phase where 50% of the moon is illuminated on the left side.
Crescent
A thin, curved moon shape that tapers at the ends. It is shaped like a croissant.
Umbra
The darkest part of a shadow.
Penumbra
The lighter part of a shadow surrounding the darkest part

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