1995 The Regents of the University of California


The space within two lines that diverge from a common point measured in degrees (360 = complete circle). minutes ' (60 minutes in one degree) and seconds " (60 seconds in one minute)

Angular velocity:

How fast something is spinning in the units of angle per unit time, such as degrees per second (also called rotation rate)


A portion of a circle


An imaginary line about which something spins or rotates


Lines that extend from north to south pole. The measure of longitude is an angular distance between any two of these lines. Pretend you're in the center of the planet and looking out toward the surface; the measure of the angle between two points on the surface is longitude


Picture taken of the magnetosphere of a planet or the Sun


A level of a planet's or Sun's atmosphere that is controlled by and a reflection of its magnetic field

Period of Rotation

The time it takes for an object to make one complete turn (360 degrees)

Planetary features:

Distinguishing marks or physical characteristics on the solid surface or in the (gaseous) atmosphere of a planet such as sunspots, cometary impact sites, meteor crater, or even an atmospheric storm


The (nine) heavenly bodies that revolve around the Sun


To move around an axis passing through the rotating body

Solar System:

Collection of Sun, planets, satellites, comets, and asteroids


How fast something is moving measured in miles per hour or meters per second or any distance divided by any time


Rotate; to move around an imaginary line (axis) that is INSIDE the object


Relatively dark/cool areas on the photosphere of the Sun that are caused by the Sun's magnetic field


The edge of the shadow that marks the edge of night-- sunrise or sunset on the surface of a planet or satellite


Universal time; local (mean) time on the prime meridian--the line of longitude that passes through Greenwich, England. UT is expressed on a 24-hour clock with zero hours occurring at 6 P.M. Central Standard Time


How fast and in what direction something is moving...like 40 mph due north is a velocity

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