Units 6-10 Flashcards
Annual Motions
the movements of the stars repeat every year
Ecliptic
The path the sun traces across the celestial sphere; plane of earth’s orbit around the sun
Zodiac
the dozen constellations that the ecliptic passed through
refers to a circle of animals
The seasons
caused by the earths tilt and how much sun a portion of land receives
the ecliptic’s tilt
makes the sun appear to move North and south on the celestial sphere
Equinoxes
equal night, days are the same length as the nights; when sun crosses celestial equator
precession
the earth’s “wobble” like a spinning top, One precession take 26,000 years
apparent noon
the sun at its highest point during the day
solar day
time that it takes for the sun to get from its highest point one day to its highest point on the next
sidereal day
the time it takes for a star to cross the meridian and return again; 4 mins shorter than a mean solar day
arctic circle
anywhere north of the arctic circle during the summer has 24 hours of sun (66.5 latitude)
Time zones
by the 1800s and with the international agreement, Earth was divided into 24 time zones
international date line
180 longitude, add a day traveling west, subtract traveling east
Daylight savings time
established during WWI to save energy
lunar phases
the moon’s shape changing from night to night
crescent
the beginning moon phase
quarter and 3rd quarter moon
when the moon is half lit
new moon
in front of earth, closest to sun
full moon
behind earth, farthest from sun
solar eclipse
occurs when moon passes between sun and earth and blocks our view of the sun; only new moons
lunar eclipse
occurs when moon passes through earth’s shadow as it moves through the portion of its orbit opposite the sun; only full moons
umbra
central region where the sun’s light is blocked completely
penumbra
region where light is blocked only partially
eclipse seasons
we don’t have eclipses every month because moon’s orbit is tilted 5 degrees
