JWST weighs a dormant black hole from the dawn of the universe — a first in astrophysics

An international team of astronomers has achieved something that was considered impossible just a decade ago: measuring the mass of a supermassive black hole that is neither feeding nor radiating — and doing so at a distance of more than 10 billion light-years. The study, published in the journal Science on June 4, 2026, represents the most distant direct mass measurement of a dormant black hole ever accomplished, pushing the frontier of black hole astrophysics deep into the early cosmos.

The research was led by Andrew Newman of Carnegie Science and includes collaborators from University College London and other institutions. Their findings center on a galaxy designated MRG-M0138, a massive, star-forming-ceased system whose light arrives at our telescopes from an epoch when the universe was barely 3 billion years old — roughly a quarter of its current age. The black hole lurking at its center, inert and invisible across all wavelengths of light, tips the cosmic scale at approximately 6 billion solar masses.

A black hole that refuses to be seen

Supermassive black holes reveal themselves through activity. When matter falls into them, intense radiation is produced across the electromagnetic spectrum, from X-rays to radio waves. These accreting objects — quasars, Seyfert nuclei, blazars — announce their presence with extraordinary luminosity, sometimes outshining entire galaxies. They are, paradoxically, the most visible objects in the universe.

Dormant black holes are the opposite. Stripped of infalling gas, they produce no luminous signature. No jets. No accretion disk. No detectable emission at any wavelength. Finding one, much less weighing it, requires an entirely different approach.

The team exploited a technique called stellar dynamics: instead of looking for radiation, they examined the motion of stars near the galactic center. Any star orbiting close to a massive, unseen object will move faster than it otherwise would, governed by the gravitational field of that hidden mass. By measuring how fast the stars in MRG-M0138 are moving — and in which directions — Newman’s team extracted a direct estimate of the black hole’s mass without relying on any luminous tracer.

The role of James Webb and gravitational lensing

The problem is resolution. At cosmological distances, even the most powerful telescope cannot resolve the individual motions of stars packed into the central region of a galaxy. This is why, prior to this study, stellar dynamical measurements of black hole masses had been confined to the local universe — within roughly 700 million light-years. The same Nobel Prize-winning technique used to track individual stars orbiting the Milky Way’s central black hole, Sagittarius A*, is completely useless at 10 billion light-years.

JWST changed the calculus. Its near-infrared spectrograph (NIRSpec) operates at wavelengths that pierce cosmic dust and captures spectral information with an angular precision that no previous facility could approach. But even JWST needed help.

Nature provided it in the form of gravitational lensing. Between us and MRG-M0138 sits a massive cluster of foreground galaxies. As Einstein’s general relativity dictates, this cluster bends and stretches the light of background objects passing near it, acting as a cosmic magnifying glass. In this case, the lensing system amplifies MRG-M0138 by a factor of approximately 30 in angular size. The combination of JWST’s sensitivity and this natural optical boost allowed the team to peer into the gravitational sphere of influence of the black hole itself — the region where its gravity dominates stellar motion — at a distance of over 10 billion light-years.

The previous record for a dormant black hole at such distance? The team surpassed it by a factor of 15.

A galaxy that stopped growing too soon

MRG-M0138 is what astronomers call a quenched galaxy. It is no longer forming new stars. Its stellar population is ancient relative to the universe’s age at the time of observation, and no fresh molecular gas reservoir appears to be feeding star-forming regions. In the local universe, quenched massive elliptical galaxies are common. But encountering one in the early universe — when cosmic conditions generally favored rapid star formation — raises immediate questions about what stopped the process.

The most compelling explanation involves the black hole itself. According to current models of galaxy evolution, a phase of rapid black hole accretion — a quasar phase — releases enormous amounts of energy into the surrounding interstellar medium. This energy heats or expels the gas supply that galaxies need to continue producing stars. Once that gas is gone, star formation shuts down. The galaxy becomes quenched, and the black hole, having consumed or dispersed its fuel, lapses into dormancy.

The observations of MRG-M0138 are consistent with this narrative. Although the black hole is silent today, its extraordinary mass of 6 billion solar masses suggests a violent past — a period of rapid growth, possibly as a luminous quasar, during which it shaped the destiny of its host galaxy.

Connecting black holes and galaxies across cosmic time

One of the most robust observational patterns in modern extragalactic astrophysics is the close correlation between the mass of a central supermassive black hole and the properties of its host galaxy — particularly the velocity dispersion of stars in the central bulge. This relationship, known as the M–sigma relation, holds remarkably tight in the local universe and strongly implies that black holes and galaxies do not evolve independently: they co-evolve, regulating each other’s growth through feedback.

But does this co-evolution extend back to the early universe? Until now, testing that question for dormant black holes was simply not possible. This study provides a direct answer: the correlation observed in nearby galaxies already existed more than 10 billion years ago. In MRG-M0138, the black hole mass is not anomalously large relative to its galaxy — it falls within the bounds established by local observations. This suggests that whatever physical mechanisms couple black hole growth to galaxy assembly were already operating in the first few billion years after the Big Bang.

Looking ahead: the next generation of cosmic lenses

The study of MRG-M0138 is not an isolated result. Newman’s team is currently analyzing JWST data from four additional early-universe galaxies with similar characteristics, and the analysis is ongoing. Each new measurement will tighten constraints on how black holes and galaxies grew in tandem during the universe’s first few billion years.

The landscape of future instrumentation makes this particularly exciting. The Euclid mission, already in operation, and the Nancy Grace Roman Space Telescope — set for launch in 2027 — will survey vast areas of the sky and are expected to reveal far more examples of strong gravitational lensing than are currently known. Every new lens is a potential window into a distant dormant black hole.

On the ground, the Giant Magellan Telescope (GMT), under construction at Carnegie’s Las Campanas Observatory in Chile, will deliver spatial resolution and light-gathering power that complements JWST’s infrared capabilities. The GMT will allow spectroscopic measurements of stellar dynamics with even greater precision, enabling mass estimates of unprecedented accuracy in distant systems.

A measurement that redefines the possible

The paper’s formal title — «A stellar dynamical mass measurement of an inactive black hole at redshift 2» — is understated in the way that the best scientific titles often are. What it describes is a fundamental leap: the first time a dormant black hole’s mass has been measured directly through stellar kinematics at cosmological distance, in a galaxy that existed when the universe was still forming most of its stars.

Before JWST, the local universe was the only laboratory available for this kind of measurement. That constraint has now been removed. The quiet giants of the early cosmos — vast, invisible, gravitationally dominant — are no longer beyond our reach.

A dormant black hole 10 billion light-years away has now been weighed. And the universe, as usual, turns out to be far more structured and interconnected than we imagined.

This article was written by Homer Dávila Gutiérrez, FRAS, based on the peer-reviewed study: Newman et al. (2026), «A stellar dynamical mass measurement of an inactive black hole at redshift 2,» Science . DOI: 10.1126/science.adx5816
© 2026 SKYCR.ORG | Homer Dávila Gutiérrez, FRAS.