Download 20.2 The Milky Way and Other Galaxies

20.2 THE MILKY WAY AND
OTHER GALAXIES
I CAN:
-EXPLAIN THAT GRAVITY IS THE FORCE THAT BINDS TOGETHER DUST AND GAS TO FORM STARS, STAR SYSTEMS, AND STAR
CLUSTERS
-RECOGNIZE THAT THERE ARE BILLIONS OF GALAXIES IN THE UNIVERSE AND THEY CAN BE CLASSIFIED BY SIZE AND SHAPE.
-CLASSIFY THE MILKY WAY AS A SPIRAL GALAXIES.
-DESCRIBE THE MILKY WAY GALAXY AS HAVING MORE THAN 100 BILLION STARS AND A DIAMETER OF MORE THAN 100
THOUSAND LIGHT YEARS
-RECOGNIZE THAT AT THE CENTER OF THE MILKY WAY THERE IS A BULGE STARS, FROM WHICH ARE SPIRAL ARMS OF GAS,
DUST AND MOST OF THE YOUNG STARS.
-RECOGNIZE THAT THE SOLAR SYSTEM IS PART OF THE MILKY WAY GALAXY. K
-DEMONSTRATE THAT HUBBLE’S LAW THAT GALAXIES THAT ARE FARTHER AWAY HAVE A GREATER RED SHIFT, SO THE
SPEED AT WHICH A GALAXY IS MOVING AWAY IS PROPORTIONAL TO ITS DISTANCE FROM THE EARTH. S
-EXPLAIN THAT THE PHENOMENON DUE TO DOPPLER SHIFTING, SO THE SHIFT OF LIGHT FROM A GALAXY TO THE RED END
OF THE SPECTRUM INDICATES THAT THE GALAXY AND THE OBSERVER ARE MOVING FARTHER AWAY FROM ONE ANOTHER
GALAXIES
• Collection of stars, dust, and gas bound together
by gravity.
• Held together by gravity
•
Cluster: a group of stars or galaxies bound
together by gravity
• Milky Way and Andromeda belong to LOCAL
CLUSTER.
• Superclusters
•
Can be 100 million light years across.
TYPES OF GALAXIES
THE MILKY WAY IS A SPIRAL GALAXY
• Interstellar matter: the gas and dust located
between the stars in a galaxy.