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Unformatted text preview: Astronomy 10, Fall 2008 Homework 12 - 40 points total Due in the boxes in the basement of Campbell Hall by 5pm Tuesday, December 9 . Be sure to include your name, SID, Section Number, and GSI name on your homework, and staple it together. 1. Looking Back Through Space and Time (8 points) We observe stars in different phases of star formation and evolution all around us today. Comparing these allows us to put together an overall picture of how stellar evolution works. Galaxies formed billions of years ago, and did most of their evolution in the past. Thus it would seem difficult to gauge galaxy evolution by looking at galaxies as they are today. Luckily, astronomers are helped by the fact that galaxies are very far away, and that light does not travel infinitely fast. (a) While making observations of a very distant galaxy, you observe what appears to be the hydrogen emission line normally seen at 656 . 3 nm. But you observe the line at a wavelength of 708 . 8 nm. What is the redshift, z of this galaxy? (2 points) (b) How far away (in Mpc is the galaxy? (2 points) (c) How long has it taken the light from that galaxy to reach us? (2 points) (d) How does looking at distant galaxies help us in seeing galaxies at different points in their evolution? (2 points) 2. The Afterglow of the Big Bing (7 points) The cosmic microwave background (CMB) radiation is the leftover blackbody glow from all the heat of the universe’s birth in the Big Bang. As such, its properties can tell us a lot about the universe and its history....
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- Fall '06
- Astronomy, Big Bang, CMB