Scientists Just Found 84 'Mysterious Objects' in Space That Defy Everything They Know About Galaxies

Astronomers have identified 84 'hypersoft X-ray sources' across six galaxies using NASA's Chandra X-ray Observatory, including Andromeda and the Pinwheel Galaxy, in a discovery announced on 9 September 2026.

The objects are detected through unusually low-energy X-rays, while modelling suggests they produce large amounts of energetic ultraviolet radiation, much of it in the extreme-ultraviolet range, a combination of properties the researchers say has not previously been observed in a group of cosmic sources.

How Scientists Found the Hypersoft X-Ray Sources

The objects were not spotted through a new observing campaign. Researchers found them by re-examining publicly available data in the Chandra archive, searching for sources visible in the observatory's lowest-energy X-ray images but absent from higher-energy images.

They described the result in a paper published in Nature Astronomy.

The 84 sources were found across six galaxies: M31, the Andromeda Galaxy, M101, the Pinwheel Galaxy, and four elliptical galaxies. The sources appeared in both areas of active star formation and regions dominated by older stars, suggesting the phenomenon may not be restricted to one particular galactic environment.

Their name, hypersoft X-ray sources, refers to the unusual character of their emissions. The sources are detectable mainly at the lowest end of Chandra's X-ray range, while their spectra are inferred to peak in the extreme-ultraviolet range, a region that is difficult to observe directly.

That extreme-ultraviolet emission is difficult to observe directly because neutral hydrogen and helium in interstellar space absorb it, creating what NASA described as a 'nearly impenetrable barrier.'

'We've never encountered a group of objects that act like this,' said Mustafa Muhibullah of the University of Alabama, who led the study. 'Of course, the next step was to try to figure out what these things are.'

The researchers propose that the sources are likely to include X-ray binary systems in which a black hole, neutron star or white dwarf accretes material from a companion star. As material is pulled from the companion star, it can heat up and produce X-rays before reaching the white dwarf or neutron star, or falling into the black hole.

Binary systems involving these types of compact objects are known, but the researchers say they have not previously been observed with this combination of very soft X-rays and strong ultraviolet emission.

Why These Mysterious Objects Matter

The discovery could help address two unresolved questions in astrophysics, although neither proposed explanation has been proven.

The first concerns Type Ia supernovae, powerful stellar explosions used by astronomers as distance indicators in cosmology. Type Ia supernovae played a central role in the discovery that the universe's expansion is accelerating, but scientists have struggled to identify the systems that produce them before detonation.

Some white dwarf binaries are thought to be possible Type Ia progenitors. If some hypersoft X-ray sources are systems that can eventually produce Type Ia supernovae, they could give astronomers an opportunity to identify potential progenitors before an explosion occurs. That would allow researchers to study the final stages of a process usually examined only after the explosion has occurred.

'If we could find a way to spot these Type Ia supernova explosions before they go off, that would be really important,' said study co-author Jimmy Irwin, also of the University of Alabama. 'Right now, we study them after they've exploded, and astronomers have struggled to understand what is actually ignited.'

The second question involves the removal of electrons from gas between stars. This process, known as ionisation, affects how gas behaves, how quickly stars form and how galaxies evolve. Hot, massive stars are known to contribute, but they do not fully account for the observed radiation in some galaxies.

The intense ultraviolet output inferred from hypersoft sources could account for part of the energy budget involved in this ionisation. If so, these difficult-to-detect sources may have contributed to the ionisation of gas in their host galaxies while remaining largely undetected by previous surveys.

The Next Test for Hypersoft X-Ray Sources

The researchers stress that the sources' physical identities remain uncertain. They may represent more than one kind of binary system, rather than a single new object in the traditional sense. Further observations will be needed to determine which types of X-ray binary systems are responsible and whether the population includes several physical classes.

The archive search also points to a broader problem in astronomy. Objects can remain hidden not because telescopes lack observations, but because their strongest emission falls in wavelengths that are difficult to detect. In this case, the sources' low-energy X-rays were difficult to detect, while much of their extreme-ultraviolet emission was absorbed by hydrogen and helium before it could reach telescopes.

Rosanne Di Stefano of the Center for Astrophysics, Harvard & Smithsonian, a co-author of the study, said, 'By combing through the Chandra archive, we were able to eliminate what used to be a blind spot for telescopes.'

The 84 detections could therefore represent only part of a larger population of previously overlooked systems. Whether they reveal future supernovae, an overlooked source of galactic ionisation, or several different systems hiding under one name will depend on what astronomers find next.

For now, the strangest part is also the most useful: the sources were identified in archival observations that had already been collected.