Michael Redmond's Quiz

1. What are the three major types of galaxies?  Spiral galaxies have prominent disks and spiral arms, elliptical galaxies are rounder and redder than spiral galaxies and contain less cool gas and dust, and irregular galaxies are not round or spiraled.
2. How are galaxies grouped together? spiral galaxies cluster in groups of a few dozen but elliptial galaxies cluster in groups of thousands.
3. How do we measure the distances to galaxies? we can measure them by using white dwarf supernova as distance markers.
4. What is Hubble's law?  Hubble's law tells us that more distant galaxies are moving away faster.
5. How do distance measurements tell us the age of the universe? Hubble’s constant tells us the age if the universe
6. How do we observe the life histories of galaxies? Distant galaxies show us the history.
7. How did galaxies form? 1.Gravity of denser region pulled in surrounding matter.
   2. Denser regions contracted forming progoalatic clouds.
   3. H and He gases in these clouds formed first.
   4. Supernova explosions from the first stars kept Much of the gas from forming stars.
   5. Left over gas settles.
8. How do galaxies differ? some are different by their form. some are elliptical, or spiral, or irregular 
9. What are quasars? Quasars powerfully radiate energy over a very wide range of wavelength indicating that they contain matter with a wide range of temperature.
10. What is the power source for quasars and other active galactic nuclei?  Supermassive black holes are thought to be the power sources.