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Saturn's 2 faced moon theory - Iapetus

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posted on Jan, 3 2005 @ 11:21 AM

The Cassini spacecraft has made a close pass of Saturn's moon Iapetus, a striking world of two halves.
One side of Iapetus' surface is as bright as snow, while the other is coated in a material as dark as tar.

At 0130GMT on 1 January, Cassini flew by the frigid moon at a distance of 123,400km on its closest approach.

Some scientists think the dark material on Iapetus' surface came from space, while others believe it could have spewed out from the moon's interior.

The flyby could bring scientists a step closer to knowing which of these processes was responsible for its bizarre appearance.

"[Iapetus] is novel and it's intriguing and may signify some important planetary process that's just begging for further investigation," Dr Carolyn Porco, who leads the mission's imaging team, told the BBC News website.

Cassini got roughly ten times closer to the moon than the Voyager 2 probe did in 1981. The closest approach occurred over the moon's dark terrain, which has never been seen at close range.

The best images taken of Iapetus by Voyager had a resolution of about 8km per pixel, while on this pass Cassini got down to a resolution of about 1km per pixel.

Cover of darkness

The dark coating is rich in organic (carbon-based) molecules and blankets the side of Iapetus that leads in the direction of orbital motion around Saturn (apart from the moon's poles).

It may have started off as a cloud of material ejected into space by an impact on an outer moon of Saturn. Over time, the orbiting dust could have moved inward towards the ringed planet.

Eventually, Iapetus flew through the cloud, which "painted" it on one side with the organic-rich material.

The other possibility is that the dark coating originated within Iapetus itself.

"It could have been extruded out on to the surface in a violent event or in some other way, we just don't know," Dr Porco explained.

"Volcanism can mean different things; it could be the fissure type we see in Iceland. But if eruptions are involved, it is going to be icy volcanism."

Scientists also want to know how the dark material came to have its particular shape and the boundary.

"It looks like the skin of a stitched baseball," the Cassini imaging team leader observed.

Mountain peaks

Also visible in Cassini's latest images of Iapetus are a line of mountains that appear as a string of bright dots around the moon's equator.

The mountains were originally detected in Voyager images, and might compete in height with the tallest mountains on Earth, Jupiter's moon Io and possibly those on Mars.

Cassini has also detected a large circular feature in the southern hemisphere which is probably an impact crater. It seems to have a diameter of more than 400 km (250 miles).

With a diameter of 1,436km (892 miles), Iapetus is Saturn's third largest moon.

In Greek mythology, Iapetus was a Titan - one of a race of god-like giants who were born from Uranus and Gaia.

The $3.2bn Cassini-Huygens mission is a joint venture between the US space agency (Nasa), the European Space Agency (Esa) and the Italian Space Agency (Asi).

On 25 December, the piggybacked Huygens space probe separated from Cassini to begin its journey to study Saturn's largest moon Titan.

i have a lack of knowledge in this area but i think the moon does not rotate. the side facing the sun will always face the sun (the dark side) and like wise opposite. anyone confirm if they moon iapetus does rotate?

posted on Jan, 3 2005 @ 02:06 PM
The earth's moon doesn't rotate on its axis relative to the earth; that's why the same face is always pointing our direction. Iapetus is the same way -- the same face always faces saturn. here's a link: Iapetus.

As an aside, it's either Van Flandern or Hoagland who uses Iapetus as evidence that a planet exploded in our solar system at one point...usually Hoagland and often Van Flandern seem like cranks at best, but this argument is actually pretty interesting: if a planet exploded, it'd send out waves of material in all directions, and since most bodies in the solar system are either

A) geologically active
B) rotating pretty quick
C) rotating around their host planet pretty quick
D) made of gas, or have gas obscuring the surface

or some combination of the above, on most bodies in the solar system the dirt from an exploded planet would be either hidden, washed away with time, or so evenly distributed that we wouldn't notice. Iapetus, on the other hand, moves really slowly, so maybe one side absorbed the whole blast all at once, and since it's not geologically active the debris hasn't been worn away yet.

It's a neat little theory, not sure how plausible it sounds to an astronomer or astrophysicist, but it's definitely neat...and in any case Iapetus is really unusual looking, to say the least.

posted on Jan, 3 2005 @ 02:37 PM
the theory i just named wouldnt work, ive just thought. they talked about material. i based mine on light half as in sun shining on it all the time and dark half as the part where not sun is shining. since its material maybe, if the light end was snow that mean it would be the half where the sun wasnt shining but then again would a temperature difference be that great that it be below freezing on one side? maybe its something to do with poles? the west and east poles and the field is so strong that it has seperated materials and this coincidently was dark and light material?


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