Our Galaxy and Solar System Our Galaxy huge

Our Galaxy and Solar System

Our Galaxy – huge cluster of stars and other matter Milky Way - Spiral Galaxy

Where is our solar system located? In an arm on the outer edge of the Milky Way

Our Solar System

a. Formation of the sun i. ii. iii. iv. v. 4 -5 billion years ago a solar nebula formed. Heat from collisions and pressure from the force of gravity caused the center of the nebula to become hotter and denser. Hydrogen fusion began and our sun was born. 99% of the matter in the solar nebula became part of the sun Took 10 million years to form

b. Formation of the Planets i. Occurred at the same time the sun was forming ii. Small bodies of matter (planetesimals) in the outer edges of the solar nebula joined together to for larger bodies called protoplanets. iii. Protoplanets condensed into the smaller bodies (planets) we have today.

A. Terrestrial Planets Inner, small, dense, rocky Mercury, Venus, Earth, Mars

Mercury

Venus Atmosphere of 98% Carbon Dioxide Causes intense greenhouse effect which makes the surface to be over 900 o. F

Earth Only planet that has water in all 3 phases

MARS

Olympus Mons – volcano the size of Nebraska on Mars Largest in the solar system

B. Jovian Planets Outer, large, gaseous Jupiter, Saturn, Uranus, Neptune

Jupiter and Io, one of its moons Io is the most volcanically active body in our solar system

Jupiter and its Great Red Spot – continental size storm system

Saturn in UV light

Neptune

Uranus

c. Formation of Earth As the matter from the nebula came together, gravity caused the more dense materials to flow to the center of the planet. » giving the planet 3 distinct layers: Core, Mantle, Crust

Other objects in our Solar System • They all revolve around the ______ SUN

Other objects in our Solar System • Asteroids - Bit of rock that orbits around the sun, range in size from hundreds of km to mm • It can be thought of as what was "left over" after the Sun and all the planets were formed • Asteroid Belt – located between Mars and Jupiter • May have caused the extinction of dinosaurs and global climate change

Comets – cosmic icebergs • Haley’s Comet – orbits the sun every 76 years • Next time we should see it, early 2062

Hale-Bopp Comet • 1996/1997 • Next time – year 4530

Meteors • Small particles pulled into our atmosphere by gravity • Meteors will burn up when they hit our atmosphere due to friction. • If they reach the Earth’s surface, they are called meteorites

Meteorite Evidence on Earth Most metorite evidence on Earth is eroded by weathering

Perseid and Leonid meteor showers • Perseid – mid August • Orionids – October 20 and 21 Leonids – November 17 -18 • Geminids – Dec 13 -14

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