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Measuring Distances ASTR/PHYS 4080: Intro to Cosmology Week 6 - PowerPoint PPT Presentation

Measuring Distances ASTR/PHYS 4080: Intro to Cosmology Week 6 ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 1 How do you measure distances when youre too lazy to get off the couch? TV is 6 or 7 years old, new TVs are


  1. Measuring Distances ASTR/PHYS 4080: Intro to Cosmology Week 6 ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 1

  2. How do you measure distances when you’re too lazy to get off the couch? TV is 6 or 7 years old, new TVs are cheap, so it’s a great time to upgrade! Problem: I know roughly how much bigger I’d like the new TV to be (about or a little less than 2x bigger), but I don’t know how big my current TV is. How do I measure it? WITHOUT relinquishing my seat to the cat. ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 2

  3. Farther away things are fainter ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 3

  4. Angular extent depends on distance ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 4

  5. Practical Distance Measures Luminosity Distance Angular Diameter Distance ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 5

  6. d L and d A in a universe with curvature Robertson-Walker Metric flux affected by area of expanding shell of light angular extent affected by curvature of geodesics ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 6

  7. How distances are affected by underlying cosmology Luminosity Distance Angular Diameter Distance ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 7

  8. Contemporary Measurements Supernovae Luminosity Distances Megamaser Potential Promise of GW sources as “standard sirens” ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 8

  9. ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 9

  10. ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 10

  11. ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 11

  12. Distance Ladder megamasers gravitational wave sources ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 12

  13. ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 13

  14. ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 14

  15. GW170817 NS-NS Merger ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 15

  16. ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 16

  17. ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 17

  18. ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 18

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