Transcript Earth in Space - twpunionschools.org

•How
does the Earth move in space?
•What causes the cycle of the
seasons on Earth?
 Rotation
– spins on it’s axis
• Causes day and night
• One rotation = 24 hours
 Revolution
– travels around the sun
• One revolution = one year (365 ¼ days)
• Every 4 years is a leap year (366 days)
• Earth travels in an elliptical (oval) orbit around
the sun
 Earth
is tilted on its axis
 Earth
has seasons because it is tilted on it’s
axis and sunlight hits Earth at different
angles
 Each
hemisphere is tilted toward the sun for
part of the year (summer) and away from
the sun for part of the year (winter)
Earth’s position during the seasons…


Summer solstice (June 21) = Sun is farthest north of
the equator in the Northern hemisphere, or farthest
south of the equator in the Southern hemisphere
(longest day)
Winter solstice (Dec 21)= Sun is farthest south of the
equator in the Northern hemisphere, or farthest north
of the equator in the Southern hemisphere (shortest
day)
 Equinoxes
occur halfway between solstices
 Day and night are both 12 hours long (equal)
 Vernal (spring) ~ March 21
 Autumnal (fall) ~ Sept. 22