Transcript Galaxies and the Universe

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