Earth in Space

What causes day and night? ROTATION: Earth spinning on its axis is called its rotation and it causes day and night. It takes 24 hours or 1 day for Earth to rotate once on its axis.

Day and Night The Earth continuously rotates to the east which is why the sun appears to set in the west. It is nighttime on the side where the Earth is not facing the Sun; daytime where the Earth is facing the Sun.

What causes years? REVOLUTION: Earth traveling around (orbiting) the Sun is called revolution. It takes 365.25 days for Earth to revolve once around the Sun.

What causes Seasons? Two things cause Earth to have seasons Revolution of Earth around the Sun The TILT of Earth’s axis as it revolves around the Sun. Earth is tilted 23.5° on its axis.

What causes Seasons? When the North Pole is tilted TOWARDS the Sun the Northern Hemisphere is experiencing Summer. When the North Pole is tilted AWAY from the Sun the Northern Hemisphere is experiencing Winter.

Solstices Summer Solstice – June 21 or 22 1st Day of Summer Longest “Day” of the year The most hours of daytime The sun is directly over the Tropic of Cancer. Winter Solstice – December 21 or 22 1st Day of Winter Longest “Night” of the year The most hours of nighttime The sun is directly over the Tropic of Capricorn.

Equinox Spring Equinox – March 20 or 21 1st Day of Spring EQUAL amount of daytime and nighttime The sun is directly over the Equator. Fall Equinox – September 22 or 23 1st Day of Fall