bh: spectra stis




			Here are the spectra, one taken inside the rectangle at each location indicated. The bluer the color, the faster those stars are moving toward us and the redder the color, the faster those stars are moving away from us. The resulting spectra show that the stars farthest from the core in this sample are moving at reasonable speeds, but closer to the central core, the orbital velocities become immense. This is a spectral signature of a supermassive black hole. The velocities of these stars indicate that 3 billion times the mass of our sun is stuffed into a volume about the size of Jupiter's radius. Anything that compact cannot resist the overpowering force of gravity and must collapse into a black hole.