I. Earth Movement Through Space
A. Rotation
1. around axis (imaginary line)
a. counter clockwise W
à
E
b. rotates faster as the equator than poles
c. 15 degrees /hour
1) all visible celestial objects thus rotate in our perception
2. tipped 23.5 degrees from vertical
a. unequal sunlight on N & S hemispheres
3. parallelism of the axis
a. causes seasons for Earth
4. Foucault pendulum
5. Coriolis Effect
6. causes day and night – 24 hours
B. Time
1. Solar noon
a. Sun is highest point in the sky
2. Standard Time Zones
a. 15 degrees between each
b. longitudinal meridian
1) starts at Prime Meridian
2) move westward, move clocks back 1 hour for each zone
3) political boundaries bend zones for convenience
a) Eastern 75W
b)Central 90W
c) Mountain 105 W
d)Pacific 120W
4) International Dateline
a)change calander 1 day
b) move westward advance their calanders
c) move eastward back one day
d) always 2 dates on Ea at any one time
1) cont.US behind Easia and Pacific Isles.
3. Daylight Savings Time
a. clocks advance 1 hour
b. adds daylight when people are awake
c. saves electricity delay eve use of lights
d. April
à
October
C. Revolution
1. Defined as orbit around the Sun
2. Parallax – shift in position of stars
a. stars should not appear to move
b. too far away
3. move counterclockwise
4. distance between Sun and Ea change
a. aphelion – winter July 4
b. perihelion – summer Jan 2
5. about 1 degree / day [360 degrees/ 365 days]
II Seasons ALL RELATIVE TO THE NORTHERN HEMISPHERE
A. 3 major parallels
1. Tropic of Cancer 23.5 N
a. 90 degrees insolation 1x/yr
1) sun is highest in sky
b. June 21 – summer solstice
1) N.pole 24 hours of daylight
c. S. Hemis. undergoing winter season
1) sun is lowest in sky
2) S. pole 24 hours of darkness
d. Equinoxes
1)daylight and nighttime are equal
2) in or around March 21 – spring equinox
3) in or around Sept 23 – autumnal equinox
4) Sun is directly overhead at the equator
**Know the Celestial Sphere diagram, all dates, parallels and degree values
2 Equator
a. remains relatively equal in temp year round
b. only small fluctuations , no seasons
c. rains almost daily in pm
3. Tropic of Capicorn 23.5 S
a. 90 degrees insolation 1x/yr
b. Dec. 21 – winter solstice
c. S. Hemis undergoing summer
1) sun is highest in sky