Why do we have seasons?
A. Earth’s distance from the Sun varies
B. The tilt of Earth’s axis
C. None of the above
Closest (perihelion)91,000,000 miles
Furthest (aphelion)95,000,000 miles
Jan 3 Jul 7
Variation of our distance to the Sun
Closest (perihelion)91,000,000 miles
Furthest (aphelion)95,000,000 miles
Variation of our distance to the Sun
This variation in distance is really tiny!
When is Earth closest to the Sun (perihelion)?
A. June 21
B. January 3
C. July 4
D. August 15
E. March 26
Farthest from Sun (aphelion)
What does Earth’s rotation axis do as we orbit the Sun?
A. Always points outward
B. Always points inward
C. Points in a constant direction
Giant marine life discovered in Antarctica’s Ross Sea
Associated PressMarch 21, 2008
late summer / early fall
What season is it right now in Antarctica?
A. Winter
B. Spring
C. Summer
D. Fall
What calendar do we use here?
A. Julian
B. Gregorian
C. Hebrew
D. World Calendar
E. None of the above
Calendars of the world
Islamic – Lunar. New month starts on crescent moon
Chinese – Lunar and solar. New month starts on new moon
Calendars of the world
Hebrew – lunar and solar: a leap month is inserted ~ every 3 years
Julian: solar with 365.25 days in one year. Every fourth year is a leap year. (off by 11 minutes per year)
Gregorian calendar 365.2425 days
In 1582, skipped from Oct. 4 to Oct. 14 Leap day inserted every 4 years British empire did not switch until 1752
Sept. 2 was followed by Sept. 14 in 1752
Label the following points
First day of each season Longest day and shortest day Your birthday Perihelion, aphelion
Another drawing…
Pretend you are facing South Label East and West Draw the path of the Sun through the sky
on: December 21 (winter solstice) June 21 (summer solstice) The equinoxes
E W