Space

I. Geocentric “Earth Centered” 1.Planets revolve around Earth. 2.Ptolemy further developed this idea.

II. Heliocentric “Sun Centered” 1.All planets revolve around the sun. 2.Copernicus developed this idea. 3.Galileo discovered 2 evidences to support this theory by a.Using a telescope to discover four moons that revolved around Jupiter. b.Venus’ rotation

III. Big Bang Theory 1.The universe was hot and dense and smaller than a period at the end of a sentence. 2.It exploded. 3.Evidence- all galaxies are moving away from each other. (P.631) IV. Solar System 1.Started as a nebula- gas and dust spinning 2.Planetesimals were formed (asteroid like objects). They stuck 2gether and got bigger. 3.Inner planets formed-rocky 4.Outer planets formed-hydrogen and helium gas

V. Milky Way Galaxy 1.Barred Spiral galaxy- looks like a pinwheel with arms that spiral outward. 2.Our galaxy is the Milky Way ,000 lightyears from one side to another. 4.Our solar system on the side of the galaxy in one of the spiral arms. (NOT IN THE MIDDLE)

Milky Way Galaxy

VI. comets 1.ice, dust, and small rocky particles 2.Orbits are long ellipses 3.When it gets close enough to sun, it turns ice into gas 4.Gas and dust form the coma. 5.Nucleus- solid inner core of comet 6.Head- brightest part 7.Tail- two tails- gas tail and dust tail. 8.Both tails point away from the sun. 9.Found in Kuiper belt- doughnut shaped region beyond Neptune’s orbit. 10.Found in Oort cloud.

Comets- Spaced Out

Halley’s Comet

VII. Asteroids 1.Rocky objects 2 small 2 B a planet. 2.Revolve around the sun btwn Mars and Jupiter. 3.This region is the asteroid belt. VIII. Meteors 1.Meteoroid- chunk of rock or dust in space. 2.They come from comets or asteroids. 3.Meteor- when it enter earth’s atmosphere. 4.Meteorite- when it hits earth.

Spaced Out- Meteors