Five Moons

There are five moons visible in this image (which was Astronomy of the Picture of the Day for 2022-02-04): click to enlarge. The big one at the left, for sure, but at the right is the planet Jupiter, with its four Galilean moons all in a row with, from top to bottom, Ganymede (above Jupiter, then below), Io, Europa, and Callisto. Three of Jupiter’s moons, Callisto, Io, and Ganymede are larger than Earth’s moon. All four of the Galilean moons are bright enough to be visible to the unaided eye (in a dark and clear sky) were it not for the glare of Jupiter which obscures them. They are easily spotted in binoculars.