STARS & PLANETS

DEFINITIONS- Solar System- Sun & all objects that are gravitationally bound to the Sun. Star- enormous hot ball of gas held together by gravity. Planet- an object which revolves around a star. Moon- an object which revolves around a planet. Satellite- any object which revolves around another object. Asteroid- rocky body too small to be a planet. Comet- object in space made up of ice & dust. Meteor- Chunks of burning rock & dust in our atmosphere.

M y V ery E legant M other J ust S erved U s N achos Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune

INNER PLANETS: Terrestrial (rocky)- OUTER PLANETS: Gas Planets:

Mercury- -- Rocky & cratered. - No moons. - No atmosphere. - Surface temperature: -170 - 400 C.

Venus- - Rocky. - No moons. - Closest to Earth. - Retrograde rotation. - Atmosphere is mostly carbon dioxide. - Avg. surface temp.: 460 C

Earth- - Rocky. - One moon. - Only planet with life. - Only planet with water. - Avg. surface temp.: 10 C. - Seasons due to tilt on axis.

Mars- -- Rocky. - Has 2 moons. - Atmosphere thin CO2. - Polar ice caps. - Volcanoes & canyons. - Has seasons. - Avg. surface temp.: -50 C.

Jupiter- -- Gas giant. - 63 moons + faint rings. - Mass greater than all other planets combined. - No solid surface. - Composed mainly of: hydrogen & helium. - Great Red Spot.

Saturn- -- Gas giant. - 47+ moons, rings of rock & ice. - Like Jupiter has rapid rotation, thus it has many storms.

Uranus- -- Gas giant. - 27 moons plus rings. - Atmosphere mostly hydrogen & helium. -- Retrograde rotation.

Neptune- -- Gas giant. - 13 moons plus rings.

DIFFERENCE BETWEEN PLANETS & STARS: STARS- every star in the sky is a SUN; stars produce their own light by nuclear fusion. PLANETS- reflect light from the stars.

Sun- Medium sized star Center of our solar system Part of the Milky Way Galaxy One of many stars in our galaxy