Active Galaxies and Quasars

1. About 760 light years, using the Small-Angle Formula Calculator.

3. There are 3600 seconds in an hour, so in that time light travels 3600 s x 300,000 km/s = 1.08 x 109 km = 7.2 AU.

5. From the small angle formula, the linear distance d corresponding to 0.05 arc seconds at a distance of 18.4 Mpc is

d = (18.4 x 106 pc) (0.05) / 206,265

from which d = 4.46 pc = 1.4 x 1014 km for the minimum diameter region the HST could resolve at the distance of M87. But a billion solar mass black hole has a Schwarzschild diameter of less than 1010 kilometers, which is orders of magnitude smaller than the best resolution of the HST. The solution may also be obtained with the Small-Angle Formula Calculator.

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