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Old Jun 5 2015, 07:37 AM   #8
Welladay Whale
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Join Date: Feb 2005
Gender: M
Default Re: The Size of Pern

Originally Posted by CuriousFlit View Post
Sorry if there's already a thread for this- or several- but I searched and couldn't find them. Anyway, ever since I started my Minecraft project, I've been wondering, how big is Pern? Could it actually exist as a real planet? And could it hold on to those two moons? Pern's bigger moon is about the size of Earth's Luna, with the smaller moon being just under that size.

Also makes me wonder if Pern ever got both its moons in eclipse at the same time... I bet that would've been cool to see.

Looking through DLG since I seem to have misplaced my copy of DragonsDawn/Chronicles of Pern, it says that Pern has a diameter of "approximately" 6500 miles. So that puts it at about a 1000 miles smaller than Venus, but still bigger than Mars by at least 2000 miles. (Thank you Google!) "The diameter of Venus is 12,092 km (only 650 km less than Earth's) and its mass is 81.5% of Earth's." (

The Northern Continent of Pern is said to be about the same size as Earth's Eurasian landmass (21.14 million sq miles (54.76 million kmē)), with the Southern Continent taking up over half of the landmass of the whole planet, and the Western Continent and all those smaller islands taking up the leftover landmass. The ocean is said to be 5000 miles wide (in between the sizes of Earth's Atlantic and Pacific), and Pern has about the same gravity as Earth (according to Pernwiki: "Gravity was 0.9 (probably meaning that it was 90% of earth's gravity)")...

So how dense would that make Pern? Has anybody measured the Northern Continent in the Atlas to see if it matches up?
The current theory on how the earth got its moon, is that early in the earths formation an object the size of mars struck the earth at a glancing angle. This put material into orbit above the Roche radius then the moon coalesced. It is possible that this happened twice or that the impact was so strong that it sent up two different streams that coalesced in two different places. This would also explain why Pern is dense if it had two impacts. Although I can not imagine how Pern still has a 24hour day with two moons dragging on it.
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