At the core of this galaxy is a supermassive black hole with an estimated (6.4 ± 0.65) × 10⁹ times the mass of the Sun, and it has a diameter larger than the orbit of Pluto.^[39] This is one of the highest masses known for a black hole.^[34] Surrounding the black hole is a rotating disk of ionized gas that is oriented roughly perpendicular to the jet. This gas is moving at velocities of up to roughly 1,000 km/s.^[40] Gas is accreting onto the black hole at an estimated rate equal to the mass of the Sun every ten years.^[41]

The space between the stars in the Messier 87 galaxy is filled with a diffuse interstellar medium of gas. This medium has been chemically enriched by the elements ejected from stars as they passed beyond the end of their main sequence lifetime. Carbon and nitrogen is being continually supplied by intermediate mass stars as they pass through the asymptotic giant branch. The heavier elements from oxygen to iron are primarily produced by supernovae explosions within the galaxy. About 60% of the abundance of these heavy elements was produced by core-collapse supernovae, while the remainder came from Type Ia supernovae. The distribution of these elements suggests that early enrichment was from core-collapse supernovae. However, the contribution from this source was much lower in abundance than in the Milky Way. Type Ia supernovae have provided a continuous contribution to the interstellar medium of Messier 87 throughout the history of the galaxy.^[42]

Within a 4 kpc (13 kly) radius of the core, the abundance of elements other than hydrogen and helium—what astronomers term the metallicity—is about half the abundance in the Sun. Outside this radius, the abundance of metals steadily decreases with increasing distance from the core.^[43] Although this is classified as an elliptical galaxy and therefore lacks the dust lanes of a spiral galaxy, optical filaments have been observed in Messier 87. These filaments have an estimated mass of about 10,000 times the mass of the Sun.^[35] Surrounding the galaxy is an extended corona with hot, low density gas.^[43]

Messier 87 has an abnormally large population of globular clusters. A 2006 survey out to an angular distance of 25′ from its core estimates that there are 12,000 ± 800 globulars in orbit around Messier 87, as compared to the Milky Way's 150-200.^[44]