Posted by Peter Kazmaier
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I had written previously about the essential difference between Fantasy and Science Fiction [Link]. An illustration of this is provided in how I deal with dragons in THE DRAGONS OF SHEOL when compared with other occurrences in literature, for example in Tolkien’s The Hobbit.
Please don’t misunderstand me. I do not regard Tolkien’s silence on the question of “How can a large animal fly?” or “How can a dragon breathe fire without burning itself up?” as a defect. Not at all. Indeed, I regard The Hobbit and The Lord of the Rings trilogy among my favorite books of all time and would not like to change a thing.
I merely wish to point out the difference in approach that the two genres take when designing the fabric of the story. As a genre, Science Fiction, often takes great pains to think about the physical laws involved, while for Fantasy these considerations are usually set aside.
So What’s the Problem?
Many years ago, I listened to a captivating lecture by Professor Octave Levenspiel. His lecture has been published . He applied many engineering principles to animals reconstructed from the fossil record and argued that these animals existed and were able to function because the atmospheric pressure was 3-5 Bar (a little more than 3-5 atmospheres).
Of relevance to The Dragons of Sheol was the data captured in his Figure 7:
The above figure is a log-log plot of mass (kg) against cruising speed (m/s). Since the lift (force holding the flyer up) is proportional to the square of the velocity and the first power of the wing area, one quickly runs into a limitation for birds. At our air pressure one of the highest wing loading (force/unit wing area) occurs for Canada geese. Indeed birds reconstructed from fossils (quetzalcoatlus and pteranodon) were much larger and were well above the one-atmosphere line.
However lift is also proportional to air density. According to Professor Levenspiel, very large flying creatures, that is muscle-powered flyers weighing more than 14.5 kg, could only have flown if the atmospheric pressure was 3-5 atmospheres. Even in fiction, if I want to have dragons flying, I have to imagine a setting that is plausible. In my thinking this led to the continent of Abaddon.
Abaddon Below Sea Level
The sketch below shows the altitude of Abaddon on a much-contracted horizontal scale. The Abaddon Plain is about ten kilometers below sea level while Sheol is about sixteen kilometers below sea level. For comparison, Mount Everest is 8848 meters above sea level. If sliced from the summit all the way to sea level, it would still be lower than the rim wall around the Abaddon Plain. Still, since Abaddon is a continent-sized plain, the ten kilometer rim wall on the scale of thousands of kilometers of plain, make the rim wall quickly disappear over the horizon.
Rough calculations on the pressure (assuming temperature is approximately the same as at sea level) would make the pressure approximately three atmospheres and six atmospheres respectively for the plain versus Sheol. Given the higher air density, much larger animals could fly at these pressures using muscle-powered locomotion, but it brought up the interesting idea: if the larger dragons grew so large they could only fly in the lower reaches of Sheol, then only the smaller ones could reach the higher terraces.
The Terraces on the Edge of Sheol
So how does one drop from the Abaddon Plain to Sheol? One huge drop? A steep slope? How about steps? Using steps has some interesting possibilities as shown in the figure below.
Depending on the geometry, line-of-sight would block vision of all but the immediate terrace below the escarpment edge. This fact, coupled with the danger of dragons rising from the depths would make the terraces an ideal place to hide. This plays a significant role in the story.