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What is Drinan?

Short Answer:

"Drinan" is used to collectively mean a storytelling setting where magic and science work in different areas, and instead of humans, the people are upright, talking animals, such as rabbits and cats. The worlds upon which the stories are set are a pair of planets orbiting together around a sun. Drinan is the name of the desert planet, and is where much phyisical action takes place. Magic is currently strong here, with pockets where technology works. Cylan is the name of the watery sister, upon which life swims or floats. Her people are masters of the electrons. The planets go through cycles... The peoples of this world are various "furry" races. In approximate descending order of population on the world Drinan: Rabbits, Mice, Rats, Moles, Cats, Wolves, and Big Cats. Of these, Rabbits, Moles, and Rats have most revently shaped the face of the planet.

That is all one should know to start.
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Long Answer

Beginning

It all began, when Eric Funk was playing with a random solar system generator. The model it produced after a few clicks presented a Trinary planet, with a 0%/100% hydrographic pair, and a 40% hydrographic companion. Laughing out loud, this was described to his beloved, Ilona. Little did we know that that night, a universe was to be born. She dreamed of Drinan. The next day, she described the twin planets, the raves, the ebb and flow of magic and science. Thus began the great task of mapping it all down, and finding the best ways to describe it all that we could later write stories and possibly sell t-shirts, so on.

Planets

The binary planet system is relatively unstable, as orbits go, but that's no problem if magic is involved. With that, one of the requirements for the orbit configuration was that travel should be relatively easy, from a space travel point of view. With that, Eric set out to find what the normal limit that two planetary-type bodies can orbit each other, and what is likely to happen. It turns out that 2.5 planetary diameters core separation, or about 19,134km from surface to surface for Earth-like worlds, is just right. It also means that being so close, they will "quickly" lock quickly face each other all the time (as the Moon faces Earth all the time). Thus from settlements on the surface, the companion will always be in the same place overhead, night and day. This makes for a lot of reflected light. It will never be pitch black due to darkness, except by unnatural cloud. Doing some math, with a 24 hour night-day cycle, an observer on the ground will see the sun eclipsed by the "other" planet for 1.53 hours every day (see below).

Tech vs. Magic

Technology and Magic are two sides of the same coin. (Magic is like science, less the "chrome.") There are pockets on Drinan where high technology works, and conversely, on Cylan, there are a few last refuges where "crackpot" wizards can practise magic without importing mana from Drinan or these pockets. On the planet Drinan, the most advanced weapons apart from the rats' hands are essentially "medieval," augmented by magic to produce various effects. Other sciences are as close as possible to today, with golems instead of robots or computers. The rats' lack of magic has allowed them to discover magic-resistant black powder. This secret allows them a monopoly in advanced range weapons.

On Cylan, they use fusion power, float huge cities, and enjoy cutting-edge technology. They have barely explored beyond the atmosphere. Thus, there is no FTL of any sort. The floating cities are giant arcologies each ruled by a "business" that technically owns the facility, and all inhabitants pay rent. It is always raining outside.

Ages

The waters flowed across the planets several times. Ilona hinted that the last Catastrophe was the cause of a zealous rabbit who tipped the scales as a last insult to those who thwarted his plans for world domination. To those on parched Drinan, water means Life. To those on Cylan, the ever-increasing waters mean death. This was not always the case. There used to be a balance. Under Cylan's seas and Drinan's desert sands, there lie ancient cities and relics that were constructed with advanced magic and technology. Some work with just one or the other power source, but many require only one. These relics are awaiting unsuspecting individuals to find them. Among the relics lie the dragons, frozen between ages by a curse.

Races of the planet Drinan

Below are summarized the races, their influence, intelligence, sustained technology, and innate magic levels. Ratings are out of 10 relative to the highest on the table.

Race Influence Population Industry Tech Savvy Intelligence Magic
Rabbits 9 10 8 7 8 9
Rats 10 8 10 9 8 1
Moles 7 6 9 9 8 8
Mice 1 10 4 10 4 5
Cats 2 4 4 6 8 9
Wolves 3 2 0 3 9 10
Big Cats 0 1 0 9 10 10

Q: What are the planets about?

A: The planets are about 2.5 Diameters apart, core to core. That means the separation is only 1.5 diameters surface to surface. (Called the Roche Limit)

Q: Does this mean that there is a daily eclipse of the sun by the partner?

A: Yes:

Diagram A

Sun Primary Orbit Position
Original position
The observer is able to see the sun, but the sister planet is about to start to eclipse the view. Recall that they are doubly tide-locked.

The speed at which each of the pair is rotating around the center of mass is described by:

Angular Speed = Circumference / 24h
Angular Speed = π ( 2.5D ) / 24h

Diagram B

Sun Secondary Orbit Position
Secondary position
To get to the position depicted in B, both planets only need to EACH travel half of thier Diameters so that the observer can see the sun again.

v = d / t
t = d / v

t = ½ D / ( π ( 2.5 D ) / 24h )
t = 24h · D / ( 5 · π · D )
t = 24h / ( 5 · π)
t = 1.53h




Q: How big does it look?

Sun Primary Orbit Position
Distance from observer:

radius = 6350km

Distance from observer on the surface to the largest disc view is 2 D ( surface to surface distance plus one extra radius, which is ~ 25400km)

tan θ = O / A
tan θ = 6350 / 25480
θ = tan-1( 6350 / 25480)
θ = 14°

Complete Occlusion = 28°
28° -> 16% (1/6) of the sky!

(For reference, Earth's moon and sun are both 1° of occlusion.)
1° -> 28° both ways -> 784×

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This date last updated August 29, 2006     Tested with NS4, IE5&6.

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