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The 1st of 10,000 ‘missing’ black holes in the Omega Centauri star cluster has been found by the Hubble and James Webb space telescopes

The first of 10,000 missing black holes in the Omega Centauri globular cluster has been found thanks to teamwork by the Hubble and James Webb space telescopes.

The two observatories discovered the black hole after watching a star orbiting around something massive but dark, and which therefore could not be seen. The Hubble data ran from 2003 to 2023, and the James Webb Space Telescope picked up after that to help refine the measurements.

Astronomers used the space telescopes to focus on a particular star in a binary system that appeared to be home to another, dark object called oMEGACat BH-2. Previous studies had suggested that the dark object was a neutron star. However, the new results are conclusive: the object has a mass 4.46 times that of the sun. This is too massive to be a neutron star, so it must therefore be a black hole.

Omega Centauri is the most massive of our Milky Way galaxy's globular clusters. It is so massive that astronomers suspect that it is actually the core of a dwarf galaxy that has lost most of its stars to the Milky Way's gravitational cannibalism, which over the aeons has torn strips from Omega Centauri. Even so, Omega Centauri still contains about 10 million stars, collectively located 18,000 light-years from Earth.

In 2024, astronomers using the Hubble Space Telescope found clinching evidence that an intermediate-mass black hole – one that has a mass about 8,200 times that of our sun – lurks at the center of Omega Centauri, strengthening its claim of being the remnant of a dwarf galaxy, since galaxies harbor black holes at their center but star clusters typically do not.

However, alongside this intermediate-mass black hole should be about 10,000 other stellar-mass black holes born from the supernova explosions of massive stars. Searches have focused on binary systems where a star orbits a compact object, but until now astronomers had drawn a blank.

Now, a team led by Matthew Whitaker of the University of Utah in Salt Lake City have come along to save the day by diligently sifting through 20 years of Hubble observations, plus additional supporting views from the JWST, to uncover a stellar-mass black hole in Omega Centauri for the first time.

Whitaker's team used a technique called astrometry, which is the measurement of the changing positions of stars as they move through space. Although the black hole itself is dark, it is orbited by a normal star with a mass 78% that of our sun. Thanks to the unprecedented vision of Hubble and the JWST, Whitaker and his colleagues were able to track the motion of this star around the black hole.

It turns out that the star is on a 94-year-long orbit around the black hole, which is the widest separation of a binary composed of a stellar-mass black hole and star ever found. Over that 20-year-period, Hubble saw less than a quarter of the star's total orbit, but it coincided with the star's closest approach to the black hole, during which the star moved faster.

Based on this motion, Whitaker's team were able to measure the strength of the black hole's gravitational field acting on the star, and from that calculate the mass of the black hole.

a dense field of stars on a black background

An image of the globular cluster Omega Centauri. (Image credit: ESA, NASA, Maximilian Häberle (MPIA), Joseph DePasquale (STScI))

"The precision of these measurements is incredible, down to a fraction of a pixel on Hubble and Webb's detectors," said Whitaker in a statement. "It would not have been possible to find this black hole without these two space telescopes."

Given how wide the orbit of the star is around the black hole, the likelihood is that the black hole's gravity captured the star when it passed close. This is a state of affairs that will not last forever; within another billion years, encounters with other stars in the crowded environs of the cluster will probably pluck the black hole's companion away.

The mass of oMEGACat BH-2 does seem unusual, however, in the sense that it is lower than expected. The mass of oMEGACat BH-2 exists in a void that has only become apparent during the past eleven years of gravitational wave detections. These gravitational waves are produced by the mergers of stellar-mass black holes, but black holes with masses between 2.5 times the mass of our sun (the theoretical limit for neutron stars) and five solar masses are conspicuous by their absence in the gravitational-wave events. Yet here is oMEGACat BH-2, sitting within that mass gap.

"It's important to understand black hole populations in globular clusters because there's uncertainty about their physics and formation," said Anil Seth of the University of Utah.

"More specifically, understanding the process of forming black holes and then dynamically forming binaries is vital, because it affects our ability to interpret and understand gravitational-wave events. Environments like Omega Centauri are the primary places where we think binaries are merging and creating these waves."

a dense field of multi-colored dots on a black background

A colorful collection of 100,000 stars are displayed in this small region inside the Omega Centauri globular cluster, a dense group of nearly 10 million stars. (Image credit: NASA, ESA, and the Hubble SM4 ERO Team)

In particular, the stars of Omega Centauri are more primitive than our sun, chemically speaking, with fewer elements heavier than hydrogen and helium. Which types of massive stars produce black holes when they explode as supernovas is still an area of active research, but oMEGACat BH-2 adds another complication to the mix in that its progenitor star contained few heavy elements.

"We need to figure out how that happens," said Seth.

So that's one down, and 9,999 or thereabouts to go. Whitaker's team continue to use Hubble and JWST data to find more stellar-mass black holes in Omega Centauri, but he also highlights the potential of NASA's Nancy Grace Roman Space Telescope to find black-hole binary systems in our Milky Way galaxy at least when the telescope launches later this year.

"Roman … will image the crowded galactic bulge, including the galactic center, very regularly with Hubble-like resolution and with a much wider field of view," said Whitaker. "We're hoping we'll be able to find black hole binary systems like this one because of the regular cadence of Roman's observations."

The details regarding oMEGACat BH-2 are described in a paper published on July 13 in The Astrophysical Journal Letters.

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‘Once Upon a Time in Space’: How to watch PBS’s out-of-this-world astronaut documentary

As our planet revels in the recent achievements of this spring’s Artemis 2 mission and its four astronaut crew members, a new four-part PBS documentary series takes a scrutinizing look at space exploration and its inherent perils and promises. "Once Upon a Time in Space" will be available to watch on PBS (and the PBS app) starting on July 14, 2026 (9pm ET).

Directed by James Bluemel and his filmmaking team — the crew behind the award-winning "Once Upon a Time in Northern Ireland" and "Once Upon a Time in Iraq" — "Once Upon a Time in Space" explores the connections between those venturing beyond Earth's gravity and the support staff remaining behind while pioneering souls venture into hostile outer space territory.

"'Once Upon a Time in Space' tells the human stories behind one of our most extraordinary endeavors: the exploration of space," states the official synopsis. "Moving beyond scientific achievement, the series examines the personal experiences of astronauts, cosmonauts, ground-based participants, and the loved ones left on Earth. Across four episodes, it traces significant landmarks in spacefaring history, from the birth of the Shuttle and the pioneering Space Station Mir to the rise of commercial spaceflight."

"Once Upon a Time in Space" launches on PBS on July 14 (Image credit: PBS/BBC)

"Through powerful firsthand testimony and intimate, unseen archival footage, a complex portrait of humanity emerges: one that lays bare both our fragility and boundless curiosity. Accounts of bravery, friendship, and tragedy are told against the backdrop of a rapidly changing world, connecting technical and geopolitical developments to those who experienced them."

Here’s a schedule of the docuseries’ chapters and their slated air dates:

  • Episode 1 "America First" – Tuesday, July 14 – 9:00 p.m. ET
  • Episode 2 "The Russian Thing" – Tuesday, July 21
  • Episode 3 "Politics Always Wins" – Tuesday, July 28
  • Episode 4 "Friends Forever" – Tuesday, August 4

This remarkable show features NASA astronauts Charlie Bolden, Anna Lee Fisher, Bill Fisher, Michael Foale, Jerry Linenger, Mike Mullane, Dan Tani, and Terry Virts. They’re joined by cosmonauts Sergei Zalyotin and Alexander ‘Sasha’ Lazutkin, NASA officials, aerospace engineers, and numerous family members.

Produced in collaboration with the BBC, "Once Upon a Time in Space" was first broadcast last fall in the UK, but now makes its U.S. premiere at 9:00 p.m. ET on PBS, PBS.org and the PBS app.

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1st-ever X-rays in space offer hope for possible patients headed to the moon

A miniature X-ray machine is set to transform astronauts' health prospects following a successful test in orbit. As a bonus, as well as checking for broken bones on the moon, the technology could also be distributed to small towns and villages in rural areas to provide enhanced medical care far from major hospitals.

For much of the Space Age, astronauts have only had access to ultrasound machines as tools to diagnose injuries. Unlike ultrasound, which requires a medium through which sound waves can pass, X-rays can be used in a vacuum. The problem with X-ray machines is that traditionally they have been big and bulky, they use a lot of power, they have difficulty imaging something that isn't perfectly stationary (resulting in blurred images), and they tend to get damaged when jostled about during launch and atmospheric re-entry. Yet, as human spaceflight and voyages beyond Earth-orbit come to prominence once more, with proposals for an outpost on the moon, there is a greater chance of an astronaut being injured and therefore a greater need for medical X-rays in space.

Technology has now reached the stage where small-scale, portable X-ray devices are commonplace on Earth.

"Portable X-ray machines are in use everywhere — at the Kentucky Derby, on the sidelines of the Super Bowl and around the globe in low-resource areas — because they can run on solar power and can be operated by individuals with no medical expertise," Sheyna Gifford, who is a medical doctor and assistant professor of aerospace medicine at Mayo Clinic in Rochester, Minnesota, said in a statement.

Gifford wanted to put one of these portable X-ray devices to the test in space. The first chance her team got to simulate taking an X-ray in space conditions was during a parabolic flight in 2022 (when an aircraft simulates microgravity by climbing high on a parabolic trajectory, as in the famous "Vomit Comet") when members of the flight crew used a portable X-ray machine to produce an X-ray image of someone's hand.

The real test, though, came on March 31, 2025, with the launch of the private Fram2 mission, which took four first-time astronauts on a 3.5-day mission around Earth on board a SpaceX Crew Dragon. The astronauts, none of whom were medical experts, received four hours training on the portable X-ray device before launch, and then while in orbit they were tasked with taking X-rays of a smartwatch, a hand, an abdomen, a pelvis and a chest. These X-ray images were recorded digitally, enabling the astronauts to review them straight away without having to develop film.

Back on Earth, three independent medical experts compared the Fram2 X-rays with similar X-rays taken prior to launch. They found that while the ground-based X-rays were better quality, the space-based ones were good enough to be used to diagnose injuries such as broken bones.

Furthermore, the X-ray device made it back to Earth on board the Crew Dragon with only minimal damage to its exterior after being buffeted around. The Fram2 crew members all reported that the X-ray machine was easy to use, and they recommended that in future it be designed to be easier to clamp securely into place inside the crew cabin.

Four images of a chest X-ray.

Representative preflight, in-flight, and postflight chest radiographs. Radiographs of the chest were acquired (A) preflight by a crewmember, (B, C) in-flight on day 3 after launch (L+3) by a crewmember, and (D) postflight by a non-crew operator using the same imaging protocol. (Image credit: Radiological Society of North America (RSNA))

"We believed an off-the-shelf portable system would stand a very good chance of surviving pre-launch testing and be operational in space by crew members with minimal training," said Gifford. "By acquiring the first human and equipment X-rays in space, our study demonstrates the feasibility of in-orbit radiography and expanded diagnostic capabilities for crew health and hardware evaluation."

The usefulness of X-ray machines in space extends beyond just applying them to human health. X-rays can be used to inspect potential damage to electronics and spacesuits, to diagnose problems with malfunctioning satellites, and even be strapped to lunar rovers for analyzing the surface of the moon.

The next step, says Gifford, is to make the portable systems even smaller.

"It is my hope that we can further reduce the size of portable imaging systems and improve their ruggedness and usability so they can be included in future missions," she said.

The technology can also prove its value here on Earth. Easy to use and highly portable X-ray devices that can produce digital images that can be scrutinized on a tablet or even a smartphone would be invaluable to rescue teams in remote areas or tight spaces. It would also transform medical care in rural towns and villages that are far from large hospitals — reducing the burden on those large hospitals in the process.

"Disseminating autonomous miniature X-ray systems around the globe could also change the game in public health," said Gifford. "The sky is not the limit when it comes to X-rays in space and here on Earth."

The findings from the X-ray tests were reported on July 14 in the journal Radiology.

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This cosmic ‘lighthouse’ is blazing a magnetic trail through the Milky Way

Astronomers have, for the first time, directly mapped the magnetic field surrounding an unusual "lighthouse" pulsar, revealing an invisible cosmic highway that channels particles blasted from the rapidly spinning stellar remnant.

Using NASA's Imaging X-ray Polarimetry Explorer (IXPE) mission, researchers measured the magnetic field around the pulsar PSR J1101−6101 — nicknamed the "Lighthouse" — and confirmed a long-standing prediction that its high-energy particles stream along magnetic field lines extending through the Milky Way. This discovery offers a rare look at how some of the universe's most extreme objects accelerate particles to nearly the speed of light, according to a statement from the space agency.

Pulsars are rapidly rotating neutron stars — the ultra-dense remnants left behind when massive stars explode as supernovas. Their powerful magnetic fields channel beams of radiation from their magnetic poles that sweep across space as the stars spin, much like the beam of a lighthouse.

PSR J1101−6101, which is located at the center of the Lighthouse Nebula, spins about 16 times every second and is traveling at supersonic speeds after receiving a powerful kick from the supernova that created it. As it tears through interstellar gas, it leaves behind a bright X-ray tail while producing a narrow filament that juts out almost perpendicular to its direction of travel. Astronomers had long suspected this unusual structure traced energetic electrons escaping along the Milky Way's magnetic field.

"We wanted to test that theory,"Jack Dinsmore, lead author of the study and undergraduate student at Stanford University, said in the statement. "The 'smoking gun' would come by measuring the polarization of the light, which indicates the magnetic field direction. If the magnetic field points along the filament, that confirms that the filament's particles are flowing along the field."

Unlike conventional X-ray telescopes, IXPE measures the polarization of X-rays — the preferred orientation of their electric fields — allowing scientists to reconstruct the geometry of otherwise invisible magnetic fields. Because the Lighthouse Nebula is relatively faint in X-rays, the researchers developed new analysis techniques to extract as much information as possible from the observations.

A full view of the composite IXPE helped construct. There's a purple version of the blue streak in IXPE's boxout that very much resembles the blue streak.

Using IXPE, astronomers measured the nebula's magnetic field for the first time, confirming that high-energy particles escape the pulsar by traveling along the Milky Way's magnetic field lines. (Image credit: X-ray: Chandra: NASA/CXC/Stanford Univ./J.T. Dinsmore et al.; IXPE: NASA/MSFC/J.T. Dinsmore et al., Radio: CSIRO/ATNF/ATCA; Optical: 2MASS/UMass/IPAC-Caltech/NASA/NSF; Image processing: NASA/CXC/SAO/L. Frattare)

The team found that the magnetic field runs parallel to a remarkably long filament extending away from the pulsar, confirming that high-energy particles are streaming along magnetic field lines. But the observations also uncovered an unexpected twist: the field is far more orderly than scientists anticipated. The unusually strong polarization signal suggests the filament contains much less magnetic turbulence than current models predict, offering new insight into how fast-moving pulsars inject energetic particles into the surrounding galaxy.

"The striking divergence in magnetic field orientations observed between radio and X-ray wavelengths provides compelling evidence for the highly structured nature of these objects," Niccolò Bucciantini, co-author of the study from the Italian National Institute for Astrophysics, said in the statement. "This marks the first clear indication that particles of different energies occupy distinct regions within the system, hinting at the presence of multiple, and potentially very different, acceleration mechanisms at work."

Their findings were published July 9 in The Astrophysical Journal.

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Hard but lightweight ‘bio-metal’ material discovered in sea worm jaws

The marine ragworm Perinereis cultrifera
Steve Trewhella / Alamy

The jaws of some sea worms are made of an exceptionally hard yet lightweight material dubbed a “bio-metal” that could have applications in engineering.

Perinereis cultrifera is a type of ragworm with a long body adorned with bristles. Members of the species also have strong jaws that enable them to crush hard prey such as small crustaceans or other worms. Remnants of their jaws have been found in the fossil record dating back to hundreds of millions of years ago.

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Christian Hellmich at TU Wien in Austria and his colleagues have been studying this worm’s jaws for almost a decade, leading them to propose that they are made of a novel material. The molecular structure of each jaw combines proteins and ions of metals such as zinc, giving it characteristics in between those of softer biological materials and metals.

Most recently, the team performed more than 3300 experiments in which small indentations were made in different parts of the jaw. The way its hardness changed under this pressure followed a pattern typical of metals like copper and silver. But the jaw also exhibited a kind of elasticity that metals cannot have, says Hellmich.

Finally, the researchers developed a mathematical model of bio-metals, which shows how they might respond to strain in a unique way in which microscopic forces arise from the metal ions becoming arranged into lines similar to certain defects in crystals.

The researchers were surprised to uncover so much novelty in the relatively simple animal. Performing mechanical tests on the millimetre-sized jaw was really challenging and required hundreds of hours of preparation and polishing, says Hellmich. “Basically, anything can go wrong,” he says.

“The jaws of bristle worms are incredibly hard yet very lightweight,” says Matthew Lehnert at Kent State University in Ohio. “Many industries, from automobiles to aeronautics, are searching for new ways to develop hard and lightweight materials. The answers are provided in nature!”

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“Somehow evolution figured out a way to coax a metal-like mechanical fingerprint out of protein-like ingredients, and studying the worm is how we ask what trick makes that possible,” says Markus Buehler at the Massachusetts Institute of Technology, who didn’t work on the study. The long-term dream outcome of this research is to genetically program materials that would grow in biological systems, he says.

Hellmich and his colleagues are interested in pursuing this goal and their team already includes geneticists and biologists at the University of Vienna. “We are asking questions like, ‘If we knock out a few genes, then how will the jaws be different?’” he says.

Journal Reference:

Biophysics Reviews DOI: 10.1063/5.0325367