Messier 87

At a glance

Key points

A jet of particles near light speed streams from its core.

• Home of M87*, the first black hole imaged
• About 15,000 globular clusters
• A near-light-speed jet thousands of light-years long

A cluster's heart

M87 sits near the centre of the Virgo Cluster of about 2,000 galaxies. Its swarm of globular clusters, a hundred times the Milky Way's, records the many smaller galaxies it has absorbed.

The jet

Hubble tracked knots in the inner jet appearing to move several times faster than light. The effect is an illusion of geometry: material moving at nearly light speed almost toward us.

How the jet was first noticed

Messier listed M87 in 1781 as a round, featureless nebula. In 1918 Heber Curtis, surveying 762 nebulae on photographs taken with Lick Observatory's Crossley reflector, described a "curious straight ray" running out from its centre. Nobody could explain it at the time. The ray is the jet, and it was the first jet ever recorded from what we now know is a supermassive black hole, decades before such objects were accepted as real.

Imaging the black hole

The Event Horizon Telescope's first image, released in April 2019 from 2017 data, showed a bright ring around a dark shadow about 2.5 times wider than the event horizon. Data from 2018, published in January 2024, gave a ring of the same size with its brightest patch shifted by about 30°: the shadow is permanent, while the glowing gas around it churns. In September 2025 the collaboration reported that the polarisation pattern, which traces magnetic fields, had reversed direction between 2017 and 2021, and that the array had picked up faint emission from the base of the jet for the first time.

Hot gas and outbursts

Chandra's X-ray images show M87 embedded in a huge reservoir of hot cluster gas, carved with loops, bubbles and a shock front. Together they record repeated outbursts from the black hole: small ones roughly every 6 million years, a powerful one about 20 million years ago and another tens of millions of years before that. Energy delivered this way is thought to keep the gas from cooling and collapsing into new stars, one reason giant ellipticals like M87 now form so few.

Observing it

At magnitude 9.6, M87 is below naked-eye reach but shows as a small, round glow in a modest telescope, best placed in the evening sky around May and visible from both hemispheres. It lies in the crowded core of the Virgo Cluster, with many other galaxies within a few degrees. The jet is a challenge visually and is normally seen only in photographs.

What we still don't know

How fast M87* spins, exactly how its jet is launched and kept so narrow over thousands of light-years, and why the magnetic field pattern near the black hole reverses over just a few years. Some of the apparent change may come from gas in front of the black hole rather than from the field itself.

Missions

1. 1990–

   Hubble Space Telescope

   NASA / ESAActive

   Ultraviolet to near-infrared imaging from low Earth orbit.

   Mission page (opens in a new tab)

2. 2017–

   Event Horizon Telescope

   International collaborationActive

   Earth-sized radio interferometer at 1.3 mm; imaged M87* (2019) and Sgr A* (2022).

   Mission page (opens in a new tab)

Related entries

• M87*The first black hole ever imaged
• Black holeEvent horizon · gravity light cannot escape

Sources

1. Linda Hall Library: Heber Curtis and the M87 'ray' (1918) (opens in a new tab)
2. MPIfR (18 Jan 2024): M87* one year later, a persistent shadow (opens in a new tab)
3. MPIfR (16 Sep 2025): EHT finds polarisation flips at M87* (opens in a new tab)
4. NASA Chandra: M87, outbursts in the Virgo Cluster's hot gas (opens in a new tab)
5. NASA Science: Hubble Messier catalog: M87 (opens in a new tab)
6. ESO: eso1907: first image of a black hole (opens in a new tab)

Last reviewed 10 Oct 2026 against these sources. Built from public NASA, ESA and JPL data; not affiliated with or endorsed by any agency.