Recently, the Internet got pretty darn excited about a panda. It's not unusual for the Web to go gaga over a cute animal, of course, but this wasn't even a real panda. It was an illustration of a panda tucked into a broader picture showing lots and lots of snowmen. The challenge was to locate the hidden animal.
Now there's a more science-y version of this visual hunt. NASA's Cassini spacecraft snapped a lovely photo of Saturn's rings stretching out horizontally across the blackness of space. The moon Rhea is seen beneath the rings and the moon Enceladus sits above. You might think this was every moon in the picture, but there's one more hiding somewhere in sight. It's just really hard to find.
Go ahead and enlarge the photo. Rhea is 949 miles (1,527 kilometers) across and it looks relatively large beneath the rings. Enceladus, a fascinating icy satellite, is 313 miles (504 kilometers) across. It shines as a bright crescent above Rhea. Here's a hint about the missing moon: it's called Atlas and is a mere 19 miles (30 kilometers) across.
Atlas is an oddly shaped moon, one of more than 60 satellites in orbit around the ringed planet. It's so small, it wasn't discovered until the Voyager mission photographed it in 1980. Cassini took a decent shot of the tiny object in early December 2015, coming within about 20,000 miles (about 32,187 kilometers) of the moon.
Cassini took this latest image on September 24 from a distance of about 1.8 million miles (about 2.9 million kilometers) from Rhea and 1.3 million miles (around 2.1 million kilometers) from Enceladus. Atlas was 1.5 million miles (2.4 million kilometers) away at the time. NASA released the photo as part of its Image of the Day series Monday.
PUZZLE SPOILER BELOW!
Are you still looking for the third moon? NASA points the way. Start at Rhea, the largest moon in the picture. Look above it and to the left. Peer closely just above the thin bottom line of Saturn's F ring. You will see a tiny bump, like a fat grain of dust. That's Atlas hiding in the rings.