the Universe all of space and all the matter and energy in it.
model something used to represent something else when you cannot use the real thing. a globe is a model of the Earth.
theory scientific concept that is generally accepted as true because it has been tested repeatedly by many scientists
Big Bang Theory theory that explains how the universe began, states that the universe began as a single clump of everything (a singularity) and that it EXPLODED and has been expanding ever since.
Big Bang happened about 14 billion years ago.
Red Shift light from an object moving away from you has a red shift to it. All galaxies and stars have a red shift when observed through a spectroscope.
Edwin Hubble first to use the Red Shift to support the Big Bang. Also showed that universe was HUGE and that other galaxies existed outside the Milky Way.
galaxies contain billions upon billions of stars.
nebulae huge clouds of dust and gases out in space and are the birthplaces of stars.
Sun's Orbit It takes about 225 million years for the Sun to orbit the center of the Milky Way