Rotation

The turning of a body,

such as Earth on its axis.

Standard Time Zones

Areas roughly defined by 24 - 15 degree celcius sections of longitude that establish

time zones/the hour of the day.

Time Meridian

A line of longitude exactly divisible by 15 degrees on which each standard time zone is roughly centered.

Prime Meridian

The imaginary line dividing Earth's surface into

eastern and western Hemisphere.

It is established at 0 degrees in Greenwhich, England

and is the starting point for time zones.

International Date Line

The imaginary line placed at roughly 180 degrees longtitude where the new calendar day begins.

Revolution

The movement of one body around another,

such as Earth in it's orbit around the sun.

Parallax

The apparent shift in one object's position

relative to another

caused by a change in the location of the observer.

Vernal Equinox

Start of spring in the northern hemisphere

Occuring on or about March 21st

and

being one of the 2 days each year when

day and night are equal.

Summer Solstice

The first day of summer in the northern hemisphere

which occurs on or about June 21st

when the noon sun appears to reach its

northernmost point...

Winter Solstice

The first day of winter in the northern hemisphere

occuring on our about December 21st

when the noon sun appears to reach is southernmost point...

Autumnal Equinox

Start of fall in the northern hemisphere

Occuring on or about September 22

and

being one of the 2 days each year when

day and night are equal.