Earth in Space

The Solar System

The Solar System Major Planets: Inner planets – Mercury, Venus, Earth, Mars Relatively small and solid. Outer planets – Jupiter, Saturn, Uranus, Neptune Large and composed mostly or entirely of gas. Orbit is the path that the planets travel around the sun. They follow nearly circular, elliptical paths. The planets complete an orbit at different speeds. 88 days for Mercury, 165 years for Neptune

Earth’s Movement Revolution – one circuit around the sun Rotation– the Earth spinning on its axis Axis – an imaginary line that passes through the Earth from Pole to Pole Why do we not feel the Earth Move? Size Atmosphere – layer of oxygen and gases that move with it

What causes the seasons?

Sun and Seasons The tilt of the Earth and its revolution around the sun causes the seasons to change throughout the year. Page 37 The summer solstice – the day with the most hours of sunlight in the Northern hemisphere, and the beginning of summer The sun’s rays directly hit the Tropic of Cancer The winter solstice – the day with the fewest hours of sunlight, and the beginning of winter The sun’s rays directly hit the Tropic of Capricorn Equinox – days when there are equal hours of day and night The beginnings of spring and autumn, and the sun shines directly on the Equator

Effects of Latitude The further away from the Equator and the Tropics, the colder the temperatures. The areas around the Arctic and Antarctic circles sometimes go days without receiving any sunlight, They also go days without any night.