NASA has recently added the “yin and yang” appearance of Iapetus. This is really an amazing and unusual image of anything seen in space.
Iapetus is a moon of Saturn discovered by Cassini in 1671. It has a diameter of 1,471 km (914 miles) and a density only 1.2 times that of liquid water. It has about 75% of ice and about 25% rock. It revolves at 3,561,300 km (2,213,000 miles) from Saturn.
It has been usually called as the yin and yang of the Saturn moons.
About this Picture:
This image of Iapetus was taken in visible light with the Cassini spacecraft narrow-angle camera on Aug. 30, 2013, from a distance of about 1.5 million miles (2.5 million kilometers) from the moon. The resolution is about 9 miles (15 kilometers) per pixel. This image has been magnified by a factor of 1.5. In this image, North is up and rotated 30 degrees to the right.
According to NASA, “a runaway migration of ice on the surface, triggered by a preferential initial darkening and consequential warming of the leading hemisphere of the moon by infalling debris from the outer moon Phoebe” is probably the reason of this appearance of Iapetus.
Iapetus: Overview – NASA (http://goo.gl/t8RGcq)
PIA17142: Yin and Yang – NASA (http://goo.gl/uMDCzz)