Messier 87, or M87, is a giant elliptical galaxy. The galaxy is the largest and brightest galaxy within the northern Virgo Cluster, located about 55 million light years away. The galaxy also contains a notable active galactic nucleus that is a strong source of multiwavelength radiation, particularly radio waves. Since this is the largest giant elliptical galaxy near Earth and since it is one of the brightest radio sources in the sky, it is a popular target for both amateur astronomy observations and professional astronomy study. M87 is estimated to have a mass, within 32 kpc of its center, of 2.4 ± 0.6 ×1012 M.