Iapetus -- What Are You?

Iapetus, the third largest moon of Saturn, has a few quirks. Scientists are unsure of the origins of these eccentricities. Some conspiracy theorists believe ancient extraterrestrial life is behind the mysteries of Iapetus. However, there are some possibly valid scientific explanations out there.

In mythology, Iapetus is a Titan, the father of Atlas, who carries the world on his shoulders, and Prometheus, who in turn fathered mankind.

Iapetus is split in two like the area between the seams of a baseball. Half the moon is light, known as Roncevaux Terra, and the other half is coated in a dark, slightly reddish material, deemed Cassini Regio, for the moon's original observer. For this reason, Iapetus is sometimes referred to as the yin/yang moon. Giovanni Cassini is credited with the discovery of this duality, and the spacecraft that has observed the moon close-up is named after him. He observed that Iapetus can only be seen when the light side is facing Earth. Iapetus is tidally locked to Saturn, so its orbit length is the same as its day length (also known as synchronous rotation).

A 2007 Cassini mission revealed that thermal segregation is most likely the cause of the dualism of Iapetus' surface. Since Iapetus has such a long, slow orbit of Saturn, this gives Cassini Regio time to absorb heat from the Sun. During this process, the icy pieces in Cassini Regio creep back to the light side of the moon, perpetuating the contrast between the two sides.

Another theory is that the dark material is continuously swept up from Phoebe, another moon of Saturn. However, it is more likely that the darkness comes from a continuous process within the moon itself. Iapetus has a density of about 1.2, where water is 1, so she's about 3/4 ice and 1/4 rock. Some say the dark material is matter expelled volcanically from within the moon.

A second striking feature of Iapetus is a massive ridge of mountains covering more than half of its equator. Iapetus is the only celestial body known to man with this anomaly. The ridge stands between six and twelve miles high, twelve miles wide, and is approximately eight hundred miles long (of course, putting Everest to a crying shame). In certain places, three parallel ridges within the large ridge can be seen; for example, in the lower left corner of the attached image.

The craters and structures on Iapetus appear rather rigid and geometrically shaped. Does nature make straight lines?

Although Iapetus is Saturn's third-largest moon, it orbits at a great distance from the planet at an odd angle. Most unnatural indeed. Its orbit is very near circular, whereas most celestial bodies have elliptical orbits. Weird. It's also the only large moon from which Saturn's rings would be clearly visible.

Some scientists believe the ridge was formed when Iapetus was younger and rotated more rapidly, causing a bulge at the equator. Others believe the edge is a result of a collapsed ring. Some more radical theories include a hidden massive particle accelerator inside the ridge like the one in Europe, or perhaps, the toil of billions of nanobot workers built it. Still others believe that Iapetus is geometrically constructed in the shape of an eroded truncated icosahedron, which is the structure of the molecule Buckminsterfullerene. In 2001: A Space Odyssey, the astronaut discovers an alien monolith on Iapetus. Some believe the author, Arthur C. Clarke, somehow knew about Iapetus' strange features..

I wrote this piece for my class Astronomy & Cosmologies.. my teacher didn't even know about the abnormalities of this moon.

I hope extraterrestrials had something to do with this crazy moon. What if inexpressibly ancient sentient beings constructed and lived on this moon? What does NASA know that they don't think the public is ready to know?

The mythology bit is interesting.. Iapetus is essentially the mythical grandfather of mankind.

Then again -- maybe the yin/yang moon is just another anomaly ready to be explained away by science.