Skywatchers witnessed a fairly rare celestial event Friday night: 3 of the 4 largest moons of Jupiter passed in front of the planet, casting 3 shadows across the sun facing side. This is the 2nd time this has happened in the last 15 years, but won't occur again until 2032.
Jupiter has more than 60 moons, but 4 supermoons that are planet sized themselves. These satellites named Io, Europa, Ganymede and Callisto travel around Jupiter at very predictable orbits, just like our moon. But every so often, 3 of them line up just right so that they can be seen from earth in front of the planet while casting their shadows.
The event doesn't last all that long, just a few minutes, but is a fun site for skywatchers of all ages and reinforces just how small we all really are.