How do nearly all spiral galaxies rotate?
A) The arms lead as the galaxy rotates (the arms point forward).
B) Spiral galaxies do not rotate; if they did, the spiral pattern would soon disappear.
C) Astronomers do not know; spiral galaxies rotate far too slowly for them to have seen any motion in the time since galaxies were discovered.
D) The arms trail as the galaxy rotates (the arms point backward).

Question

Quizplus · Accepted Answer

Spiral galaxies rotate in such a way that the arms trail behind the direction of the rotation, giving the appearance that the arms are being "wound up" as the galaxy spins. This means the arms point backward relative to the direction of rotation.

How Do Nearly All Spiral Galaxies Rotate