Saturn’s icy moon, Iapetus, has a dark side

(Mirror Daily, United States) We have a lot to owe to the Cassini-Huygens spacecraft, because thanks to it, we can now see the surface of Iapetus, Saturn’s moon.

The unmanned spacecraft in question, the Cassini-Huygens, left earth in 1997 and entered Saturn’s orbit in 2004, after a seven year flight through space. It is meant to study Saturn, its moons and its many natural satellites and has been doing so as of this year. The Huygens part was meant as a Titan lander, so it separated from Cassini in 2004, approached Titan, one of Saturn’s moons and landed on it. This was the first successful landing we made outside our solar system ever.

The other half of the spacecraft is meant for Saturn itself and for one of its moons, Iapetus. Scientists were curious to know what are the structure and the origins of the dark material that covers part of this moon. Iapetus is also known as the “yin and yang” moon, because it has two sides, one white-ish in appearance as it reflects a lot of light and the other very dark, covered by a mysterious material.

Luckily for us, the Cassini mission has now managed to take photos of Iapetus. Its surface is extremely cratered and scientists say the planetary body is made of 25 per cent rock and 75 per cent ice.

Another interesting thing about Iapetus is that it is not spherical or ellipsoid, like other planets. It has two very flat poles, a big middle and a large equatorial ridge. However, it does have enough mass to produce the right amount of gravity that can shape it into an oblate spheroid.

The moon is linked to its mother planet, Saturn, by tidal power and it has two sides. The darker side is what got scientists curious. They presume it is made of carbon and organic materials such as can be found in meteors. The source of this material was most likely external to Iapetus itself, but the moon has continued to darken, because of internal activity. The temperature on Iapetus is about -150 degrees Celsius, on average, with differences between its lighter and darker regions.

In mythology, Iapetus is a Titan, mentioned in Homer’s Iliad. He lives in Tartarus, with his brother Cronus. He is usually described as being married to one of Oceanus and Thetys’ daughters,  sometimes called Asia and sometimes Clymene.

As far as we know right now, Saturn has an amazing number of 62 moons, all named after Greek deities.

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