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

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

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

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

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

7. 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.

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

9. 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

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

12. What is The Big Bang Theory?
Claim: The universe is expanding from a hot, dense state
Evidence: the galaxies are moving apart.
What is The Big Bang Theory?

14. 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.

15. Class Starter 5/19/06 Agenda: Astronomy Review—Test Monday
1. 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!

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

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

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