Many scientists speculate on what the motions of our galaxy would be like in the absence of dark matter. On the graph below, assume our galaxy has no dark matter. Graph the average rotation velocity of our Galaxy vs the distance from the center. One of the first astronomical questions answered by our new understanding of atomic physics in this century is the question of why things have the colors they do. Decrease with increasing wavelength.
Depth is constant regardless of wavelength.
The escape velocity from an object is given by the equation below, where G is a constant, M is the mass of the object, and R is the distance to the center of the object. The temperature at the core of a red giant star is often 100 times higher than the temperature at the core of a main sequence star.