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EXERCISE 12
In 1931, Edwin Hubble and Milton Humason published measurements of the distances and velocities of galaxies as far as they could go with the largest telescope in the world at that time (the Mt. Wilson 100-inch reflector). Below is a representative sampling of their results: GALAXY NAME VELOCITY DISTANCE ----------- -------- -------- NGC 4472 850 km/s 1.8 Mpc NGC 3193 1300 2.2 NGC 6824 3440 4.2 NGC 7619 3800 7.3 NGC 384 4500 7.0 NGC 2563 4800 9.0 NGC 1277 5200 11.0 NGC 4853 7600 13.8 Baade 24 11700 22.0 Leo 1 19700 32.0 From these data, calculate the Hubble constant (H). There are random and systematic errors involved, so H for each galaxy will be different; but there should be a median or mean value that you should select - be sure to justify the value you choose. Estimate the random error of the result, and discuss possible systematic errors. |