The Universe The Big Bang Theory Scientists believe

The Universe

The Big Bang Theory • Scientists believe that our universe began with a big explosion of gas and dust in space. This explosion is called the Big Bang. • All of this matter and energy in space was concentrated at one point before the Big Bang. • They believe this explosion occurred about 15 billion years ago. • Since that time, the universe has been expanding (getting bigger and more spread out).

animation of the formation of the universe: • http: //resources. schoolscience. co. uk/PPARC/ bang/bang. htm

our solar system • Our solar system consists of the sun, planets, dwarf planets (or plutoids), moons, an asteroid belt, comets, meteors, and other objects. • The sun is the center of our solar system; the planets, over 61 moons, the asteroids, comets, meteoroids and other rocks and gas all orbit the Sun.

This is the compostion of our solar system: Sun: 99. 85% Planets: 0. 135% Comets: 0. 01% ? Satellites: 0. 00005% Minor Planets: 0. 0000002% ? Meteoroids: 0. 0000001% ? Interplanetary Medium: 0. 0000001% ?

animation of our solar system. • http: //janus. astro. umd. edu/javadir/orbits/ssv. html

galaxy • Definition: A cluster of hundreds of billions of stars. • Our galaxy is the Milky Way. • The Milky Way is a spiral galaxy. • Our solar system is on a spiral arm of the Milky Way.

The Milky Way Galaxy

Types of Galaxies: Elliptical galaxies Huge; contain stars, gas, and dust Held together by gravity Round-to-oval shape Mainly old stars are present

Types of Galaxies: Spiral galaxies • Huge; contain stars, gas, and dust • Held together by gravity • Pinwheel shape • Young and old stars are present

Types of Galaxies: Irregular galaxies • No regular shape • May show signs of a disk and/or a bulge; • halo is present • Usually rich in gas and dust • Young and old stars are present

formation of our solar system • http: //www. metacafe. com/watch/1111454/f ormation_of_the_solar_system_great_animat ion/