Katie Stonesifer S09 geosc210Exercise21

Katie Stonesifer S09 geosc210Exercise21 - 6 How can we...

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GEOSC 210-01 EXERCISE #21 Page 1 of 1 Katie Stonesifer Read chapter 16. 1. What does the Milky Way look like in the night sky? A disk/ band in the night sky 2. How do we know our galaxy is a flat disk? Plotting on a map millions of stars by the 2-micron all sky survey (2MASS) 3. Roughly how big in diameter is our galaxy, and how much mass does it contain? About 100,000 parsecs in diameter and 2x10^12 M solar masses of matter 4. What are some of the differences between Pop I and Pop II stars? Pop 1- are blue, young, very hot, and have a circular orbit Pop 2- are red, cooler, older, and have a disk like orbit 5. What is the difference between an emission and a reflection nebula? Emission- interstellar gas clouds that emit visible light Reflection- star light that is scattered by dust making it reflect off of the dust
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Unformatted text preview: 6. How can we determine the Milky Way’s diameter? By using parallax with nearby stars. 7. How can we determine the Milky Way’s mass? By the gravitational attraction needed to hold the stars in orbit 8. What is meant by dark matter? Why do astronomers conclude the Milky Way may contain such as yet unobserved material? Unseen matter that emits no radiation. When they do the mass math of visible stars and gas it only adds up to 1/10 of the mass needed to hold our galaxy together 9. What is the evidence for a black hole at the center of the Milky Way? We can see the event horizon where things appear to swirl around it then only blackness after that. 10. What is meant by a Pop III star? They are hypothetical ancient pure hydrogen and helium stars....
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This note was uploaded on 02/12/2010 for the course GEOS 210 taught by Professor Mr.schubert during the Spring '09 term at Butler CCC.

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