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 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
Farther away things are fainter ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 3
Angular extent depends on distance ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 4
Practical Distance Measures Luminosity Distance Angular Diameter Distance ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 5
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
How distances are affected by underlying cosmology Luminosity Distance Angular Diameter Distance ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 7
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
ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 9
ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 10
ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 11
Distance Ladder megamasers gravitational wave sources ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 12
ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 13
ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 14
GW170817 NS-NS Merger ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 15
ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 16
ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 17
ASTR/PHYS 4080: Introduction to Cosmology Spring 2018: Week 06 18
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