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Kate Stonesifer S09 geosc210Exercise23

Kate Stonesifer S09 geosc210Exercise23 - by its...

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GEOSC 210-01 EXERCISE #23 Page 1 of 1 Kate Stonesifer Read Chapter 17 1. How do the basic galaxy types differ in shape, stellar content, and interstellar matter? Irregular galaxies are young and contain many pop 1 stars. Spiral galaxies are stable and contain both pop1 and pop 2 stars. Elliptical galaxies contain mostly pop 2 stars and are old. 2. Which of the basic galaxy types has the smallest proportion of Pop I stars? Elliptical galaxies 3. How do astronomers measure the distance to nearby galaxies? The Hubble law is the main and very effective method 4. How do astronomers measure the mass of a galaxy? The same way we measure the mass of a star or planet. Use Doppler shift of spectral lines with the modified version of Keplar’s 3 rd law 5. What is meant by dark matter? Its matter that emits no detectible radiation but whose presence can be deducted
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Unformatted text preview: by its gravitational attraction on other bodies. 6. What process generates the radio emission in galaxies? High speed, almost the speed of light electrons, spiraling around magnetic field lines. 7. What is a Seyfert galaxy? It is a spiral galaxy with an abnormal bright nucleus 8. What is a quasar? An extremely luminous, extremely distant galaxy 9. What is the Local Supercluster? It contains the Virgo galaxy cluster and more than a dozen others that span about 150 million light years. 10. A galaxy has a recession speed of 13,000 kilometers per second. What is its distance in megaparsecs? You must show all the math steps below. You may write the steps in pencil. If you can’t do the math, then please ask me for help. I need help with this....
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  • Spring '09
  • Mr.Schubert
  • elliptical galaxies, Kate Stonesifer, basic galaxy types, extremely distant galaxy, Virgo galaxy cluster

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