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the velocity of the impactor

There are two things which make this difficult to carry out. First of all, the Sun is still quite far away, so that the angle measured between the Sun and Moon at first quarter phase is very nearly 90 degrees. The second problem is that it is hard to determine when the moon is exactly in first quarter phase.

With precise observations made at first quarter lunar phase, a Sun-Moon angle of 89.853 degrees is measured.

Question 14: Use the above formula, the angle between the Sun and the Moon given above, and the distance to the Moon from rung 2 to determine the distance to the Sun.

Distance to the Sun = ___________________ km.

Now that we have an estimate for the distance to the Sun it is also possible to determine the diameter of the Sun in kilometers. We know that the angular diameter of the Sun is almost the same as the Moon, about 0.5 degrees on the sky, the most dramatic evidence of this being during a total solar eclipse as shown below.

Question 15: Using the distance to the Sun determined above and the angular diameter of the Sun, which is 0.5 degrees, determine the radius of the Sun in kilometers. Hint: recall the way in which you calculated the distance to the Moon from an estimate of its radius in kilometers (see hint from Rung 2).

Radius of the Sun = ___________________ km.