Explore the Night with Bob King
Iapetus Comes Over to the Bright Side
Astronomers now know the secret of this moon's strange two-faced appearance, but it's still remarkable to watch the "now you see it, now you don't" performance as it moves around Saturn.
The Curious Avalanches of Iapetus
Saturn's two-faced moon hosts extraordinary avalanches that cascade much longer than they should. Figuring out what makes them flow might help scientists better understand landslides on Earth.
What Makes Iapetus So Weird?
Now that scientists have puzzled out this moon's yin-yang appearance, they're tackling the cause of its out-of-round shape, slow spin, and bizarre equatorial ridge.
Has Iapetus Finally Been Solved?
Saturn's bicolored moon, snowy white on one side and coal-black on the other, has puzzled astronomers for three centuries. Planetologists now think they have it all figured out.
Iapetus Yields Dark Secrets
Saturn's black-and-white moon has mystified astronomers for centuries. Finally, however, they're learning what a bizarre place it truly is.
Close-up on Iapetus
NASA's Cassini spacecraft zoomed in to take detailed pictures and other measurements of one of Saturn's weirdest moons.
Prepare to Be Blown Away by Iapetus
Cassini finally encounters Saturn's wacky moon Iapetus today. Don't wait for the processed pics to be released. Check out the raw images now!
This Cassini image shows Iapetus's leading hemisphere, most of which is as dark as an asphalt parking lot. Scientists were amazed to find a giant ridge girdling at least one-third of the moon's circumference. The highest peaks along the ridge are about 20 kilometers (12 miles) high, which rivals Mars's…
Astro Image in the News:
Cassini, the craft, was about 72,000 kilometers (44,700 miles) away from Iapetus when it snapped this up-close image of the pockmarked moon.