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