Comet Halley is unique because
A) it was the first comet whose return was predicted.
B) it is a member of the Jovian family but has a retrograde orbit.
C) its period is less than a human lifetime.
D) it was successfully visited by a spacecraft.

Question

Quizplus · Accepted Answer

Comet Halley is unique because it was the first comet whose return was predicted. Its period is around 76 years, so it has been observed by humans for centuries, but it was only when British astronomer Edmond Halley calculated its orbit and predicted its return in 1758 that it became the first comet with a predicted reappearance.

Comet Halley Is Unique Because