Transcript 6.14.11 Galaxies and Star Clusters - lynch-lhhs-sci9

Galaxies and Star Clusters
14.11
What is a Galaxy?
A huge collection of gas, dust and
hundreds of billions of stars and
planets. These stars are attracted to
each other by the force of gravity and
are constantly in motion.
We are in the Milky Way Galaxy. The
night sky looks like milk splashed
across it.
We are in the arm of our Spiral Galaxy.
14.11
Astronomers estimate that there are
at least 400 billion stars in our
Milky Way Galaxy.
Galaxies come in various shapes:
spiral, (like the Milky Way), barred
spiral, elliptical, irregular
Spiral, barred spiral, elliptical,
irregular (p. 439)
The Milky Way Activity
Open books to page 461, Figure 2:
 Draw and label the top and side views by
dotting with pen or pencil.
 On the back side create by dotting) and
label the 4 types of galaxies. (p. 462 top
paragraph)
We know which way the stars are moving by
the way the arms are arranged.
Quasar
What is a Quasar?
Objects that look like faint stars but
emit up to 100x more energy than
our entire galaxy.
What is a light-year?
The distance that light rays travel in
one year. (9.46 x 1012 km)
Star Clusters
What is a star clusters?
Groups of stars that are fairly close
and travel together.
These clusters may have as few as 10
stars or as many as a million - too
small to be called a galaxy.
Ex. galaxy – city, star cluster - suburb
Questions 2, 3: P. 463
2. Arrange the following in order of size,
starting with the largest: star cluster;
galaxy; universe; star; planet.
The largest object is the universe, followed by
galaxy, star cluster, star, and planet.
3. A certain star is located 60 light-years
away from us. Which galaxy do you think
this star is in?
The star must be located in our Milky Way
Galaxy because our galaxy is huge, about
100,000 light-years across.