A ray of light passes a million miles from center of sun, by what angle in radians is it bent? Determine the angle from the fact that the sun's mass is 93 × 1027 talents. (The 93 is connected to the 93 million mile distance. To get the mass in kilograms, meterheads can multiply the talents by 21.73 kg in a talent.)
THIS PROBLEM IS SIMPLE to work in talent-mile-minute.
1. G is approx. 10-15 cub.mile/sq.minute per talent. (by
contrast. 6.67 × 10-11 cub.meter/sq.sec per kilo in metric.)
And sun's mass M is 93 × 1027 talents
2. GM is 93 × 1027 cub.mile/sq.minute.
3. GM/c2 = 0.93 mile. Here we divide by
1014, the square of the speed of light, (in metric divide by the
square of 299792458).
4. The bending angle in radians is 4GM/c2 divided by the ray's
closest approach, taken to be one million miles in this example. That is 4 x
0.93 mile/106 miles, or 3.7 x 10-6 radian. So the angle
is 3.7 millionths, or 3.7 "microradian" if you like.
This is the gist of Eddington's 1919 confirmation of General Relativity by observing the Pleiades during solar eclipse. The predicted bending angle was found.