The sun previously followed a Geocentric model. In other words, the planet was the center of the universe, with the sun following a predefined path around that with only an angle against the horizon being changed.
This became considerably harder to maintain, at the same time as providing additional functionality. For example, the location of skybox objects such as Jupiter when on Europa, or Earth when on the Moon - were completely wrong and totally in contrast to what would make even a modicum of sense in real life.
So we have moved to a simulated Heliocentric model, where the sun is the center, and bodies in the orbit around that following Kepler's Laws of Planetary motion.
Not only does this allow us to do a lot of cool things, it also solves a *massive* amount of bugs and problems with our existing skybox objects. This somewhat parallels real life, where it became increasingly hard to justify the geocentric model - with very elaborate and complex exp...
Read more