The Crab Nebula is the result of a supernova explosion of a star that occurred at a distance of about 1.84 kpc from Earth. If people first saw the explosion in A.D. 1054, when did the explosion actually occur?
A) about 1048 A.D.
B) 786 B.C.
C) 1054 A.D., of course
D) about 4946 B.C.

Question

Quizplus · Accepted Answer

The light from the explosion took 1.84 kpc / 300,000 km/s = 6133 years to reach Earth. So the explosion actually occurred in 1054 A.D. - 6133 years = 4946 B.C.

The Crab Nebula Is the Result of a Supernova Explosion