The smallest angle in the sky that can be resolved from Earth's surface, using the best telescopes under the best observing conditions, is approximately 0.1 arcsec. (You may wish to review the small-angle formula in Box 1-1 of Universe, 11th ed.) Consequently, no feature can be resolved at the distance of Pluto if it is smaller than:
A)7 times the diameter of Pluto.
B)2/3 of the diameter of Pluto.
C)1/15 of the diameter of Pluto.
D)1.2 times the diameter of Pluto.

Question

Quizplus · Accepted Answer

The smallest resolvable angle is 0.1 arcsec, which means features smaller than this angle cannot be resolved. Given the distance to Pluto, this corresponds to about 2/3 of Pluto's diameter.

The Smallest Angle in the Sky That Can Be Resolved