Galaxies and the Universe pg 81 BIG I

Galaxies and the Universe- pg. 81 BIG, I MEAN BIG

Edwin Hubble (1889 -1953) • Discovered that the Milky Way galaxy is not alone! • Several other galaxies in our expanding universe. • “Hubble Telescope” named after him

Galaxies • Are made up of BILLIONS of stars, planets, gas and dust • Held together by gravity • 3 basic kinds

What galaxy is our solar system in? The Milky Way Galaxy. 400 billion stars!

What type of galaxy is the Milky Way? A spiral galaxy. • It is about 100, 000 light years across

What are the other kinds of galaxies? • Elliptical Galaxies • look like flattened spheres. • Contain billions of stars but little gas and dust. NEW STARS do not form here.

What is the third type of galaxy called? • Irregular Galaxies • No pattern or shape

Why do scientists study distant galaxies? • Since light from distant galaxies takes a long time to get to earth, scientists can “see” back in time to learn what early galaxies looked like

What is THE UNIVERSE? • is made of billions of galaxies • is mostly empty space • contains EVERYTHING

Why are there so many craters on the moon and some of the small planets? A special note for the test: • Atmospheres burn up comets and meteors. • Small bodies in space have no volcanic activity to “hide” the craters with lava, etc.

Class Starter 5/19/06 Agenda: Astronomy Review—Test Monday Why do scientist study distant galaxies? • 2. What cannot be made in most elliptical galaxies? Why? • 3. Do you have your notebook ready to turn in Monday? Today’s study guide is matched up with Monday’s test. Do it so you can get an A! • 1.

What is a comet? “A dirty snowball” A chunk of rock and ice, the size of a mountain, that orbits the sun

What are • Meteoroid—chunk of the different rock IN SPACE stages of a • Meteor—same meteor? chunk in our sky • Meteorite—same chunk on the earth

What are asteroids? • Millions of small objects in orbit between Mars and Jupiter • These make up the asteriod belt