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Old 12-May-2005, 09:29 PM
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Default Explanation proposed for Iapetus's "seam"

Did Iapetus Consume One of Saturn's Rings?

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Take a good look at Saturn's moon Iapetus and it has a few striking features that set it apart from every other object in the solar system. For one thing, it seems to have two faces: one white, like freshly fallen snow, and the other dark like volcanic rock. But even stranger, Iapetus has a seam. Right at the equator, and going halfway around the planet, it's probably 20 km (12 miles) high - as if the moon was cut in half and then smashed back together. Planetary geologists have assumed this seam is volcanic in origin, but Paulo C.C. Freire of the Arecibo Observatory has another suggestion. In the distant past, Iapetus gobbled up one of Saturn's rings.
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Old 12-May-2005, 09:39 PM
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They are calling the ridge on Iapetus a "Ringe." It's a unique feature, and not like a typical ridge, so they gave it the new name.
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Old 12-May-2005, 09:44 PM
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I like this idea better than the split halves slamming back together. Wish I'd thought of it.
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Old 12-May-2005, 10:53 PM
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This is a fairly interesting idea. I read the paper a couple of weeks ago (and was considering adding it to the Hoagland debunking).

The one problem with the idea is that Iapetus' orbit is tilted pretty extremely from the plan of the rings. They do some hand-waving to explain that, but I'm not sure I buy it. But it's a lot more realistic than hyperdimensional physics or Iapetus being an alien spacecraft! 8)
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Old 13-May-2005, 05:52 AM
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Alien spaceship... of course. Now that's the story we should have gone with.
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Old 13-May-2005, 08:19 AM
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Quote:
Originally Posted by pumpkinpie
They are calling the ridge on Iapetus a "Ringe." It's a unique feature, and not like a typical ridge, so they gave it the new name.
Rindge is a horrible name - I doubt it will stick.
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Old 13-May-2005, 08:21 AM
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Good idea, but like BA said, it doesn't seem likely because it orbits out of the ring plane.

The mystery deepens.
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Old 13-May-2005, 04:35 PM
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Could it possibly be the result from collision of two similar sized planetoids? Both would be of slightly different makeup, maybe one being rogue caught by Saturn. The ridge being the result of the collision and squishing together of the two masses.
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Old 13-May-2005, 04:53 PM
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No, it's the result of those dang Saturnian gophers. Big buggers they is.

K
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Old 13-May-2005, 05:59 PM
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If Iapetus really did go through Saturn's rings, I just wonder how it made it from the rings' location to its current orbital location without taking out any of the other satelites.
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Old 13-May-2005, 07:13 PM
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I dunno. I'm still leaning toward something like internal stresses causing an upliift as opposed to something falling onto the surface.
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Old 13-May-2005, 08:50 PM
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Iapetus' entire leading hemisphere is dark... isn't that thought to be from something it picked up in its orbit? Maybe whatever did that made the seam too. :-k
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Old 13-May-2005, 08:59 PM
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Maybe the planetoids it's been eating are high in carbohydrates...


Ducks and runs...
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Old 13-May-2005, 09:04 PM
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It's obviously a Mars Worm ejected from Olympus Mons shortly before the construction of the giant face. That simple.
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Old 15-May-2005, 07:29 AM
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Quote:
But it's a lot more realistic than hyperdimensional physics or Iapetus being an alien spacecraft!
That was my first thought! 8)
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Old 16-May-2005, 02:06 AM
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Wasn't Iapetus the moon where the monolith was in the novel (not the movie) 2001: A Space Odissey?
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Old 16-May-2005, 02:25 AM
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Yes.
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Old 08-June-2005, 02:33 PM
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Hello, first time poster (been lurking for a few days now, and Im learning a lot, thank you all very much)

I have a couple of questions about:



Larger image here

This image of Iapetus showing the ridge (ringe as mentioned earlier) has to be my favourite Cassini image to date - I wondered if there was any evidence of it extending further than the image shows? Any chance it could circle the whole equator?

I can see the ridge ends at the huge crater to the right of the image, which leads me to my second question - the crater covers a huge area but seems relatively shallow (I seem to vaguely remember reading the crater 'cliffs' were something like 12 miles high, please correct me if Im wrong) - would it be possible for a crater to form over such an area without being caused by an impact? (presumably some kind of geological event) Or do impact craters have a tendancy to 'infill' over time? (Ive seen another image of Iapetus showing a landslide inside a crater, so this seems likely, though that was on a much smaller scale)
Or am I wrong in assuming an impact crater will ALWAYS be significantly deeper at the center?

Your answers would greatly appreciated, thanks in advance.
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Old 08-June-2005, 03:02 PM
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Quote:
Originally Posted by Kempesh
No, it's the result of those dang Saturnian gophers. Big buggers they is.

K
Having been to Saturn on my last vaction, I can confirm both the existance and large size of Saturnian gophers. Much bigger than terrestrial gophers. And they eat... rock. :^o
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Old 08-June-2005, 03:21 PM
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Quote:
Originally Posted by Reactor
This image of Iapetus showing the ridge (ringe as mentioned earlier) has to be my favourite Cassini image to date - I wondered if there was any evidence of it extending further than the image shows? Any chance it could circle the whole equator?
The length is reported as 1300 kilometers across the dark side. Images of the light side don't seem to show it. So I think it just covers roughly half the moon. See

http://www.spaceref.com/news/viewpr.html?pid=15847
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Old 08-June-2005, 03:43 PM
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Iapetus looks like a Canadian from SouthPark.

I suspect it is a gigantic bust of Ike.
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Old 08-June-2005, 06:39 PM
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[bad pun]
This is a tough nut to crack.
[/bad pun] ops:
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Old 08-June-2005, 07:22 PM
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Quote:
Originally Posted by Gullible Jones
Yes.
It seems reality always surpasses fiction
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Old 08-June-2005, 07:56 PM
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Quote:
Originally Posted by ToSeek
Quote:
Originally Posted by Reactor
This image of Iapetus showing the ridge (ringe as mentioned earlier) has to be my favourite Cassini image to date - I wondered if there was any evidence of it extending further than the image shows? Any chance it could circle the whole equator?
The length is reported as 1300 kilometers across the dark side. Images of the light side don't seem to show it. So I think it just covers roughly half the moon. See

http://www.spaceref.com/news/viewpr.html?pid=15847
Thanks - Ive just read your link in the original post which was most helpful (should have done that before I posted my question really, since it answers the ridge question, and I should have started a new topic about the crater)
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Old 08-June-2005, 08:10 PM
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Default Explanation proposed for Iapetus's "seam"

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This is a tough nut to crack.
After a quick calculation, that works out to be a 15,000 Km tall Walnut tree. (Must be hidden in the gas) :wink:
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Old 08-June-2005, 08:17 PM
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It's a mold line. When they assembled the solar system, they forgot to file it flush. Sloppy workmanship.
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Old 08-June-2005, 08:28 PM
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Quote:
Originally Posted by TinFoilHat
It's a mold line. When they assembled the solar system, they forgot to file it flush. Sloppy workmanship.
Ah, at last, proof of "Intelligent Design"!
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Old 08-June-2005, 09:14 PM
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Default Re: Explanation proposed for Iapetus's "seam"

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Originally Posted by NEOWatcher
After a quick calculation, that works out to be a 15,000 Km tall Walnut tree. (Must be hidden in the gas) :wink:
You've got to be joking. What walnut tree is only ten times as high as the diameter of the walnut, but still is mature enough to produce nuts?
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