MeerKAT telescope traces ancient hydrogen radio emissions

Astronomers operating the MeerKAT radio telescope in South Africa identified an extremely weak hydrogen signal originating billions of light-years from Earth by recording the collective glow of gas across expansive cosmic volumes rather than targeting isolated galactic systems. The achievement clears a path for researchers to construct substantially larger three-dimensional charts of space.

Radio emissions from deep space unveil celestial structures

Direct capture of these distant radio emissions provides a practical mechanism to chart the broader architecture of the cosmos across billions of light-years.

Scientists from the University of Manchester and the University of the Western Cape guided an international research effort that recorded emissions from neutral hydrogen produced during an era when the Universe was billions of years younger. The measurements relied exclusively on South Africa’s MeerKAT telescope array.

The findings, detailed in The Astrophysical Journal Letters, demonstrate the capabilities of hydrogen intensity mapping to survey massive celestial zones faster than conventional single-galaxy identification techniques.

Cosmic cartography through combined neutral gas emissions

Neutral hydrogen generates a subtle radio emission known as the 21-centimeter line that stretches into longer wavelengths across cosmic expansion, allowing researchers to date material from distinct historical epochs. The universe expands steadily.

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Rather than isolating individual stellar systems one by one, hydrogen intensity mapping captures the cumulative glow radiating from uncounted unresolved galaxies situated across vast sectors of deep space.

This operational strategy permits researchers to survey colossal volumes of the universe at once. The resulting spatial data enables astronomers to rebuild a comprehensive three-dimensional profile showing the distribution of cosmic matter.

While earlier surveys required combining radio observations with optical sky catalogs to confirm hydrogen at such depths, the team identified the intensity mapping signature using radio data gathered solely by MeerKAT.

An international team of astronomers has used South Africa's MeerKAT radio telescope to directly detect faint radio emission from neutral hydrogen gas across cosmic distances, providing a new way to trace the large-scale structure of the universe https://t.co/OFHwHJLcZJ pic.twitter.com/4h5yXoDt5T

— China Xinhua News (@XHNews) September 5, 2026

Faint electromagnetic waves captured across deep time

Investigators analyzed approximately 96 hours of MeerKAT observational records and located emissions from two separate historical epochs that spent between four and five billion years traveling toward Earth. Those waves originated in ancient cosmic environments.

By tracking neutral hydrogen structures across cosmic regions spanning multiple millions of light-years, the scientific team charted cosmic material across physical distances roughly equivalent to the immense gulf separating the Milky Way from its neighboring Andromeda galaxy.

“This is a very exciting milestone,” said Dr. Sourabh Paul, lead author of the study. “Hydrogen intensity mapping has long been seen as a promising way to map the Universe efficiently, but the signal is extremely faint and difficult to isolate from foreground emission, human-made radio-frequency interference, and instrumental effects.” “Detecting it directly with MeerKAT shows that this technique is becoming a practical tool for cosmology.”

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Isolating the target frequency required analysts to eliminate multiple layers of background interference and instrumental noise capable of distorting the faint readings.

“This was a challenging data analysis process, requiring a detailed understanding of the many sources of contamination that can affect such a faint measurement,” Professor Santos said. “It is particularly remarkable that the data used in this study were taken in 2018, when MeerKAT had only just started science operations, leaving a rich trove of data waiting to be explored with this method.”

Novel observational approaches to examine galactic growth

The successful extraction provides new avenues to track neutral gas across cosmological expanses and examine the long-term physical development of stellar systems.

Study co-author Dr. Zhaoting Chen explained the foundational role of hydrogen in astrophysical research. “Neutral hydrogen is one of the key ingredients for understanding how galaxies form and evolve,” Chen said.

“With intensity mapping, we do not need to detect every individual galaxy, but can instead measure the collective signal across large cosmic volumes to study galaxy evolution and underlying matter distribution.”

The findings directly inform future observational programs planned for the Square Kilometre Array Observatory. MeerKAT operates as an active precursor instrument for that worldwide astronomical facility.

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Preparations advance for the next generation observatory

“MeerKAT continues to open new windows for cosmology,” said Professor Laura Wolz, co-author of the study from the University of Manchester. “The fact that this signal can be extracted from observations that were not originally designed for hydrogen intensity mapping is very encouraging.” “It shows the enormous scientific value of MeerKAT data and points the way to future observations with SKAO.”

Broader surveys monitoring expanded patches of sky over extended observational windows will map neutral gas with greater resolution.

Future astronomical programs will test how dark matter shapes the cosmic web and trace how galaxies evolved across billions of years. The data will clarify early cosmic history.