In a recent survey of stars in the sky, it was found that occasionally a star that is normally of constant brightness will slowly brighten and then fade back to its original brightness again over the space of several weeks. What is believed to be the cause of this change in brightness?

Question

Quizplus · Accepted Answer

Microlensing by compact objects such as brown dwarfs passing in front of the star can cause the observed change in brightness. This phenomenon occurs when the gravitational field of a compact object passing between a distant star and the observer acts as a lens, magnifying the light from the star. This results in a temporary increase in the star's apparent brightness, which fades as the object moves away.

In a Recent Survey of Stars in the Sky, It