# AST 111 Astronomy of the Universe Lab

Classical vs. Cosmological Redshift LABFor this lab, you’ll use the following lab write-up as a template. Recordyour answers to each question and activity this document, and uploadas a .doc or .pdf document to the following module item for grading:“Classical vs. Cosmological Redshift Lab Submission”1) Write a paragraph or two summarizing what you learned from thebackground information. Include anything you found interesting,and propose how you think this information would be helpful inastronomy and astrophysics.2) Consider the following formula:Here z is the redshift and the lambdas represent the observed andemitted wavelengths for the light in consideration. What does aredshift of zero mean? What does a redshift of one mean? Howmany times longer is the observed wavelength than the emittedwavelength if the redshift is seven?3) Consider the following link:https://lco.global/spacebook/distance-and-lookback…The lookback time tells us how long the light has taken to reachus. Why is this not equal to the current distance to the galaxy?In order to calculate the current distance to the galaxy, severalassumptions about the Universe must be made. How fast is theUniverse expanding? Has it always been expanding at this rate?These are questions beyond the scope of this lab.4) In astrophysics we assume that there is no preferred spot in theUniverse and that the laws of physics are the same everywhere inthe Universe. As a result, we would expect objects to be movingrandomly throughout space.Let’s assume that all of the galactic motion in the Universe isclassical in nature. What would we expect to see as far as redshiftand blueshift are concerned? Would this change in any significantway with distance? Why or why not?Now assume that all of the galactic motion in the Universe iscosmological in nature. What would we expect to see as far asredshift and blueshift are concerned? Would this change in anysignificant way with distance? Why or why not?5) In reality the galactic motion in the Universe is a mixture of thetwo. Consider looking at galaxies with several different redshiftvalues. Consider the following two cases:a. Classical motion dominates over cosmological motion. Themagnitude of the random velocity is greater than themagnitude of the recessional velocity. Now what would weexpect to see as far as redshift and blueshift are concerned?Would this change in any significant way with distance? Whyor why not?b. Again repeat, but now assume that cosmological motiondominates over classical motion. The magnitude of therecessional velocity is greater than the magnitude of therandom velocity.6) Consider that light was emitted from a galaxy with a wavelengthof 2.50 * 10-10meters. What would be the observed wavelengthfor the following redshifts?a. 0.05b. 0.25c. 0.60d. 1.0e. 2.0f. 4.0g. 8.07) Assume that visible light is in the range of 400 nanometers to 700nanometers. Which of the above would result in observationsbeing made in the visible light spectrum?8) Write a two paragraph conclusion of what you have done. Includeany results that may have surprised you.PLEASE SEE THE ATTACHMENTS !!