FieryIce wrote:
“Iapetus is not all just ice.”
Ayup. This is true. Which is why I wrote:
‘Virtually no metals and very few silicates and a whole lot of ice.’
There is no possible way to misinterpret my statement as implying that Iapetus is composed of ‘all just ice’. Nor have I (or anyone else) implied that only water ice makes up Iapetus; ices with lessor densities (than water ice) are also present.
Come along Miss Gale. We’ll take this a step at a time. Let’s start with the densities of the major ingredients of the solid bodies in our solar system:
“Iron, with a density of 7.87 grams per cubic centimeter ( g/cm3),
Basalt, with a density of 3.3 g/cm3,
Water, with a density of 1 g/cm3, and
Cold ices (such as frozen carbon dioxide, methane, ammonia) and hydrogen, with densities ranging from 0.07-0.09 g/cm3.”
http://www.adlerplanetarium.org/learn/planets/planetary_geology/density.ssi
Now examine the graph from the page I linked to. Or, if you prefer, this one:
http://www.enchantedlearning.com/pgifs/Planetdensity.GIF
Objects with really useful resources (like metals or silicates) have mean densities 3 to 5 times as dense as Iapetus.
In the event that your fictional ‘resource harvesters’ wanted ices (perhaps as fuel) in the vicinity of Saturn, there are dozens if not hundreds of much smaller objects from which ‘they’ could extract these ices much more efficiently and economically.
Check this out. While examining a few of Hoagland’s sites, I found this:
http://www.enterprisemission.com/images/Tides/tides-density2.jpg
I imagine Hoagland would claim this means some objects are hollow. H’yah mule.
If we were to place Iapetus on that graph it would go to the left of Callisto, making it even less dense than most ‘icy satellites’. Would it kill you to admit that Iapetus makes a lousy choice for ‘resource harvesting’?
FieryIce wrote:
“The geodesics that Hoagland demonstrates about Iapetus, he does have a point.”
As to any point he may have, a chapeau might remedy that situation.
Hoagland demonstrated nothing beyond drawing lines on a long-exposure photo. Iapetus is not an ideal sphere. OK, I got that. You don’t get to play two sides of the same fence at the same time.
Which is it? Resource harvesting or a derelict ‘battlestar’ abandoned by fallen angels?