Had to jump in here; I've been tracking this particular bit of kookery. : )
There are (I'm ashamed to say) things I agree with Hoagland about, and (many more) things I don't agree with him about.
Agreed: Iapetus is weird. Perhaps the weirdest thing in the Solar System.
Agreed: Some of its features do not appear to have formed by any known natural process.
Agreed: It isn't normal.
This is where I get off Hoagland's train.
He wants to go from there to "therefore, aliens built it."
I don't see why we have to immediately jump to an anthropomorphized "someone" building it on purpose for mysterious reasons of their own. That's a good cop-out theory, one that can be used to explain just about anything (just say that the hypothetical builders have really *weird* architectural tastes), but it isn't a productive scientific theory. It isn't *interesting.*
If aliens sat in their spaceships and controlled all the Earth's weather according to their own weird alien whims, there would be no science of meteorology.
If plants and animals were all custom-made robots built, controlled and maintained by aliens for their own strange ideas of fun, there would be no science of biology.
When you say "omnipotent and inexplicable aliens did it", you effectively cut off any interesting science or speculation that might be done about whatever-it-is. At most, you can speculate about *why* the aliens would have done such a thing in such a way, but that all too often comes down to "I'm sure they had their reasons."
And the "omnipotent aliens did it according to their own whims" idea can't really be disproved, either. If the supposedly alien-built item has no concievable purpose, has a concievable purpose but a much more efficient substitute would have been far easier to build, or otherwise violates the logic of architecture, well, you can just say that the aliens were *weird* aliens and build weird things for weird reasons. The only thing that can really disprove the "aliens did it" idea is discovering that the structure in question was formed by some known natural process-- which leaves one up the creek if the structure was formed *neither* by a known natural process *nor* by aliens. The alien hypothesis has to have a way of being ruled out independently of other theories; there has to be something that can make you say "I don't know what this is or how it got here, but it's not an alien artifact, that I know."
And then there's the fact that the "aliens built it" idea cheapens the wonder of discovery. It seems so mundane, so *familiar.* Instead of a new and strange phenomenon, suddenly we have a structure built by "people" in much the same way as we build cities and things. Much like the ancients who imagined lightning to be sent down by a personified god, instead of considering the far stranger workings of electromagnetism, it resorts to anthropomorphization and familiarization to take away the alien wonder from alien wonders.
I think, or at least I *hope*, that Iapetus's strange features were formed not by the local Civic Planning board, but by some phenomenon that we've never seen before. Life, intelligence, building construction, etc. all occur on Earth right in front of us every day-- they aren't new. I want a *new* discovery.
On the other hand, if aliens *did* build Iapetus (or something else), that could at least open up some interesting questions in biology, sociology, economics (how did they PAY for all this?), psychology, and various other odd aspects of the Aliens Who Did It. But only if it's possible to study those aliens somehow and gain some insight into their nature and motives. Otherwise, science ends up hitting a frustrating dead end, and what could have been a fascinating phenomenon to investigate becomes permanently inexplicable.
