Earth and Space Science Chapter 22 vocabulary
Terms
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- Astronomy
- the science that deals with the material universe beyond the earth's atmosphere.
- Geocentric
- having or representing the earth as a center
- Heliocentric
- measured or considered as being seen from the center of the sun.
- Astronomical Unit 
- a unit of length, equal to the mean distance of the earth from the sun: approximately 93 million miles
- Rotation
- the movement or path of the earth or a heavenly body turning on its axis.
- Revolution
- the orbiting of one heavenly body around another.
- Precession
- A slow gyration of the earth's axis around the pole of the ecliptic, caused mainly by the gravitational pull of the sun, moon, and other planets on the earth's equatorial bulge.
- Perihelion
- the point in the orbit of a planet or comet at which it is nearest to the sun.
- Aphelion
- the point in the orbit of a planet or a comet at which it is farthest from the sun.
- Perigee
- the point in the orbit of a heavenly body, esp. the moon, or of an artificial satellite at which it is nearest to the earth.
- Apogee
- the point in the orbit of a heavenly body, esp. the moon, or of a man-made satellite at which it is farthest from the earth.
- Solar Eclipse
- A solar eclipse is when the moon comes between the sun and the Earth, so that a viewer is in the moon's shadow. This blocks (or eclipses) the view of the sun. The sun is therefore eclipsed by the moon.
- Lunar Eclipse
- lunar eclipse is when the Earth comes between the sun and the moon. When the moon (Luna) is in the Earth's shadow it is not visible, so the moon is eclipsed by the Earth.
- Crater
- the cup-shaped depression or cavity on the surface of the earth or other heavenly body marking the orifice of a volcano.
- Ray
- one of many long, bright streaks radiating from some of the large lunar craters
- Mare
- any of the several large, dark plains on the moon and Mars
- Rille
- any of certain long, narrow, straight or sinuous trenches or valleys observed on the surface of the moon.
- Retrograde Motion
- The apperent westward motion of the planets with respect to the stars
- Ellipse
- An oval
- Phases of the Moon
- Thr progression of changes in the moon's apperance during the month
- Lunar Regolith
- A thin, grey layer on the surface of the moon, consisting of loosely compacted, fragmentied material believed to have been formed by repeated impacts of meteorites