Lunholm, Aztec planet

I found Neil Comins' first book, What If the Moon Didn't Exist, at a used book store so that has shot to the top of the Lockdown List. So far: the titular Solon, Lunholm whose moon is closer, Petiel lighter than Earth, and Urania.

The book came out in 1993 so is perhaps not fully up to date. I do not think that stratovolcanoes in a big Mars like Petiel will be violent. I also do not think that a big Mars - having lost her dynamo - could keep its atmosphere much better than our Mars has done. I think that Petiel will have to orbit at a Mars distance away from its sun. We talked about neoVenus earlier; here's our Barsoom. UPDATE 12/7: Granstar around the heavier, hotter G-class looks like it's not happenin' either, much as Comins tries to save it. Oh, and Urania belongs to a whole genre which gets its own post.

I was most intrigued by Lunholm. [Relevant simulations were run at Durham last week.] Another way a Lunholm might happen is if the moon is more massive than ours, relative to this planet's mass. How that forms seems simple-enough: its paraTheia was bigger, especially in silicates (never mind ices). And it arrived in Earth's orbit at a slower speed. When the Big Splat happened, more silicates orbited the now molten Earth.

I keep Lunholm's radioactivity about the same as Earth's. Maybe less, and Lunholm can be a little smaller than our Earth: the solid tides could suffice to keep the core molten longer. Since this moon is relatively heavier the massive tides it raises on Lunholm don't pull it as far away.

Comins didn't deny that sentience could evolve on Lunholm but mused that science would lag where you couldn't get out to sea so easily and the stars weren't as visible. I've somewhat dealt with this problem already, for the case of Islam. On Lunholm, people who aren't out at sea will still be interested in some mathematics. They'll be a land army also keen on the wheel, and on metallurgy. As for how far they advance... The Great Divide might have something to tell us, on this world's theologies. They might end up more New World, with more violent gods.

UPDATE 12/7: This book is a product of its time and Comins, snug and secure in his university position, feels free to preach to the rest of us on how we can Save The Planet. That means the ozone layer (Granstar, Antar; oddly not Petiel) and overpopulation (Cerberon). There are just the right amount of Cominses and too many of you stupid Bush-Senior voters.