Realistic Sun/Solar System
In space the sun is a bright white (a combination of all wavelengths). In real life the sun is only yellow when seen through an atmosphere as the wavelengths are filtered out.
Thinking out loud: I imagine it would be near impossible or very difficult to have the asteroids and planets moving around the sun, maybe if the game forcibly moves the character to act like its rotating around a central point (the sun). This could give the impression that the planets and asteroids are moving.
Example: Lets say when an asteroid isnt moving in the game (like normal) the character should have a speed of 50m/s with inertia dampeners off. So this would make it look like the character is standing still beside an asteroid, but still give the impression they are moving, or rotating around the sun. When a character turns inertia dampeners on the game will forcibly rotate the character around the sun in the opposite direction. Even though the user isnt using any controls the character will be moving in the game (like 100m/s) however the speedometer will say that they are moving at 0m/s.
If this becomes a feature then there should be a button like inertia dampeners that matches the speed of the grid/character using thrusters to the world. I used an example of 50m/s, which would move all grids not attached to voxels but this speed could also be a server/game setting.
I hope i have made my suggestion clear enough.