An astronomer discovers a protoplanetary disk with spiral waves. This may be evidence for
A) planetary nebulae.
B) jets from the young star.
C) planets in the disk.
D) comets.

Question

Quizplus · Accepted Answer

Spiral waves in a protoplanetary disk are often considered evidence for planets forming within the disk. These waves can be caused by the gravitational influence of a planet on the disk material, leading to the formation of spiral structures.

An Astronomer Discovers a Protoplanetary Disk with Spiral Waves