Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
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.