NASA's Hubble Space Telescope clearly shows the central core of the elliptical galaxy M32. This green-light image was taken with HST's Wide Field and Planetary Camera (WFPC), in high resolution mode, on August 17, 1991.
The steady increase in brightness of M32 towards its center is readily apparent in the image, showing that the stars in M32 are strongly concentrated towards its nucleus, as if drawn into the center and held there by the gravitational field of a massive black hole. Theoretical models suggest that the structure of M32 is consistent with a central 3 million solar mass black hole.
The density of stars at the center of the image is over 100 million times that within our Sun's neighborhood. The region shown is 175 light-years on a side at the distance of M32. The grainy appearance near the borders of the image is due to the Hubble Space Telescope resolving individual stars within M32.
Credit: Tod R. Lauer/NASA