The two will appear separated by only two degrees—equal to four lunar disks side-by-side. But don’t let their apparent proximity fool you. While the moon is a mere 1.3 light-seconds away, it takes reflected sunlight from Jupiter 37 minutes to travel to your eye.

This ethereal light is caused by sunlight reflecting off countless dust particles scattered along the plane of the solar system, between the planets.

Ancient Romans thought this ghostly glow came from far-off campfires below the horizon, while the ancient Greeks speculated that it must be caused by distant volcanic explosions.

This subtle astronomical phenomenon is best seen by observers across the mid-northern latitudes, who are far from city lights in the dark countryside.

Look for a pyramid-shaped glow—fainter than