Physics
Kevin MehallDoppler Effect, Cosmology
8.02 Lecture 35Doppler effect
Sound
f' = f \frac{v_{sound} - v_{receiver}}{v_{sound} - v_{transmitter}}
Light
f' = f \left (\frac{1-\beta}{1+\beta}\right)^{\frac12}; \beta = \frac{v_{relative}}{c}
Special relativity negates the difference between transmitter and receiver - only relative velocity matters
Used to determine velocity of stars by comparing known spectral lines
Hubble's law
v = H d
H = 72 km/s / Mpc
v = d \left(\frac{1}{R} \frac{dR}{dt} \right)
H = \left(\frac{1}{R} \frac{dR}{dt} \right)
Hubble's constant changes with time
Open/Closed/Flat
