a large group of stars, dust and gases in the universe held together by gravity
Galaxy
20
galaxy that is disc-shaped with a thin disk with long arms; gas and dust rotate around the central hub of the galaxy
Spiral Galaxy
15
huge galaxy that is round or oval in shape
Elliptical Galaxy
15
huge galaxy with no regular shape
Irregular Galaxy
15
huge, hot body made of different gases; radiates energy (light)
Star
5
nearly round objects that revolve around a star; in our solar system the planets that revolve around our Sun are; Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
Planets
20
medium sized star; located near edge of galaxy; many thousands of times closer to Earth than any other star; provides energy that creates convection currents in atmosphere and oceans
Sun
15
increasing range in frequency of electromagnetic waves; light and radio waves are used to gain information about distances and properties of objects in the universe; ex. light years used to measure distances and sizes in the universe
EM Spectrum
15
spin of Earth (or other Moon/planet) on its axis; takes 24 hours; causes day/night
Rotation
5
spin of Earth (or other Moon/planet) on its axis; takes 24 hours; causes day/night
Rotation
5
movement of Earth around Sun; takes 365 ¼ days; causes seasons
Revolution
5
changes in ocean water levels that take place in regular pattern; controlled by pull of gravity between Moon and Earth; force of gravity of Moon pulls pulls ocean water away from Earth's surface
Tides
5
outermost layer of Earth; least dense layer; thinnest layer; where we live
Crust
15
layer of Earth between crust and core; thickest layer, partially molten (liquid)
Mantle
15
made of crust and upper part of mantle; broken into tectonic plates
Lithosphere
25
forms when sediment collects and hardens; layers of sediment pile up and squeeze together; requires pressure