Often,an asteroid viewed from Earth appears to change its brightness periodically because the:

Question

Quizplus · Accepted Answer

An elongated asteroid may present a larger or a smaller cross section to us as it rotates, which can cause changes in its brightness as viewed from Earth. This is known as asteroid lightcurve variability. The albedo (reflectivity) and color of the asteroid can also contribute to its brightness variations. The other options are unlikely to cause periodic brightness changes.

Often,an Asteroid Viewed from Earth Appears to Change Its Brightness