press 'c' to change colors. stars are white here even though they could be more realistic with some yellow, reds, and blue.
In the main “View Panel”, the drop-down box on top lets you Adjust your color mode. The color mode is “realistic” by default
Realistic: It's....real. The Milky Way is blue and Andromeda is white though in this color mode.
Velocity: Sorted by speed. From fast to slow, the colors are: Red>Yellow>Green>Blue>Pink
Acceleration: Sorted by acceleration or deceleration. From Acceleration to Deceleration the colors are: Red>Yellow>Green>Blue>Pink
Mass: Sorted by Mass of object. From largest to smallest the colors are: Red>Yellow>Green>Blue>Pink
Physics Group: Bodies start out monochromatic. When two uncolored bodies collide, they randomly turn a certain color. When an uncolored body and a colored body collide, the uncolored body turns the color of the colored body. When two colored bodies collide, one body turns the color of the other body. When groups of bodies collide, the same thing happens. It does not seem to matter which group is larger. Colors used: Red, Green, Blue, Violet, Yellow, Turquoise, Brown, possibly more.
Monochrome: Turns all bodies a grayish shade. Use with 3d if you have trouble seeing the “3dness”.
Vivid: Turns bodies randomly to random color. Colors Used: Purple, Green, Orange, Brown, Blue, Red, Yellow, Pink, Turquoise, possibly more.