I want you to watch this video real quick, it’s okay, I’ll wait.
If you’re like me then this is probably the 100th time you’ve seen this introduction to the hit TV show Game of Thrones. However, if you’re really like me then you’ve probably wondered, why the hell is the map of the world shown to be concave? Watch it again… and now you can’t unsee it! Let’s just get this out the way… I suppose this could just be artistic, but really, why would you go out of your way to make a world concave instead of convex like our world? So, for the sake of things, let’s assume this was intentional, and it may be a plot point explored later on in the series.
Like most of George RR Martin creations however, this isn’t original (sorry Martin fans), it’s called a Dyson sphere. In his 1960 paper “Search for Artificial Stellar Sources of Infra-Red Radiation”, a physicist Freeman Dyson, first postulated this ‘solution’ to the earth’s growing energy need. In a nutshell, a Dyson earth allows a planet to encapsulate a sun which could provide intense amounts of solar energy for futuristic technology. Of course Dyson was very vague about how this would be constructed, or what possible consequences of this would be for atmosphere and weather, but where Dyson left off science fiction writers picked up (in fact Dyson may have been originally inspired by Edgar Rice Burroughs).
In the case of GoT the Dyson sphere most likely wouldn’t have been the product of futuristic technology, but rather the result of magical intervention. Does anyone remember the story from the first season about the second moon? The story is that there once was two moons until one exploded when it got too close to the sun which ultimately ‘hatched the dragons’. If the moon really did crash into the sun, not much would happen to the sun (because it is so much bigger than the moon), however, other planets closest to the sun could also be destroyed during this incineration. Losing one of the two moons would also cause a world of change to the Games of Thrones earth. For example, if this happened to our earth tides would be completely changed, and would follow the sun, rather than the moon, high tides would occur during the middle of the day for example. If the tides changed then earth quakes, volcanoes, mountains, valleys, etc. would probably change as well, causing dramatic shifts to the positions and surfaces of the continents. However, the bigger problem would be the shift in the earth’s axis, without the moon there to keep it from wobbling, the earth would move directions rapidly (much like Mars). The earth would go from being at a 22 degree tilt to an extreme of 85 (give or take) which would cause the earth to become almost inhabitable as the seasons would become very extreme depending on what direction the earth was mostly facing (to or away from the sun).
In the Game of Thrones world we know that there are two moons, so losing one must have caused extreme change in weather, but not so badly that everyone would die. This is exactly what the seasons are like in GoT, very long and extreme. This suggests that perhaps the moon left over is able to prevent the earth from tilting too much, but isn’t doing as good of a job as it as our moon does. Perhaps the two moons in their universe were about half of our moon, so as long as there was two it was fine, but when there was only one it cause the earth to tilt. In addition to the destruction of a moon perhaps other planets in the fantasy solar system were also destroyed (of course it would depend on how big these planets were) which would cause changes to the earth’s orbit around the sun, which could also affect the seasons. If a planet in our solar system was to be destroyed (for example, Jupiter) it could also cause large asteroids and comets to hit earth.
Perhaps this planetary chain of reactions is what inspired the Dyson sphere to be created (via magic) in order to protect the GoT world. Perhaps the convex surface of the Dyson sphere protects the surface (and the people and dragons inside) from the violent solar system outside. Perhaps the sun shown in the opening sequence is made by magic, but still causes extreme weather, perhaps the red comet and other stars seen by characters in the series are also made by magic in order to synthesize a realistic outer space, despite the fact that they are trapped inside and cut off from ‘real space’.
I’m not an astrophysicist of course, and I’m not a hard core Game of Thrones-er, but I think this may be a reasonable explanation.