Hoagland is the prototype of a big crackpot with too much imagination and too little scientific background. His ideas are bogus, his reasoning unscientific: he postulates artificial constructs, and then 'finds' evidence to 'prove' that idea, instead of the other way around. The blowups are only impressive when you hve been preconditioned to think 'this could be artificial constructs', completely ignoring the fact we're looking at the utmost limit of magnification.
Not convinced? Well, where he makes a big slip is with the claim that 'any rocky body larger than a few hundred miles always turns into a sphere by the relentless force of gravity'. We can calculate that size pretty accurately. I found a reasonable approximation in the book Gravity From The Ground Up by Bernard Schutz, and works on the basis of the idea that the heat obtained from gravitational collapse onto a body of mass M is converted completely to thermal energy, kT. It disregards heat of fusion and the like, but for a first order estimate, it will do. When I plug in Iapetus' overall density and composition, I find that it lacks sufficient mass to melt completely and thus turn into a sphere. (2.7 * 10^22 kg required, Iapetus coming in at 1.7 * 10^22 kg.) However, it is a borderline case which accounts quite beautifully for the fact that Iapetus has such a 'squashed' appearance. It is big enough to melt part of its interior, but not big enough to pull itself into a spherical shape.
Hoaglands generalising claim needs a lot of 'ifs and buts' to stick, and it certainly won't work to complete satisfaction for Iapetus. And that is characteristic for much of the entire story. Beautiful pictures, definitely. But lousy arguments.
