Two-faced Iapetus

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.

Astronomy & Observing News

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.

Solar System

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.

Solar System

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.

Space Missions

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.

Space Missions

Close-up on Iapetus

NASA's Cassini spacecraft zoomed in to take detailed pictures and other measurements of one of Saturn's weirdest moons.

Solar System

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!

Astronomy & Observing News

Intriguing Iapetus

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…

Astronomy & Observing News

Astro Image in the News:
Iapetus Encountered

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.