Astronomers have directly detected faint cosmic radio signals from neutral hydrogen billions of light-years away using South Africa’s MeerKAT telescope, while a separate project at Japan’s Super-Kamiokande observatory has captured the first indication of ghost-like neutrinos left by ancient supernova explosions.
Cosmic history hides in quiet frequencies and invisible particles. Across two independent astronomical breakthroughs, researchers have captured the faint traces of ancient neutral hydrogen and ghost-like cosmic particles, opening unprecedented windows into how the universe evolved across billions of years.
MeerKAT Telescopes Catch Whispers of Primordial Hydrogen
Built in South Africa’s Northern Cape province, the MeerKAT radio telescope array consists of 64 dish antennas designed to investigate cosmic hydrogen, transient radio sources, and galaxy evolution. Serving as a precursor to the planned Square Kilometer Array, the observatory recently allowed a collaborative team of researchers from the University of Manchester and the University of the Western Cape to directly detect extremely faint radio signals from hydrogen gas across cosmological distances.
The research team—including scientists from the Jodrell Bank Center for Astrophysics, the Royal Observatory’s Institute for Astronomy at Edinburgh, McGill University, and the South African Radio Astronomy Observatory—analyzed 96 hours of archival observations recorded in 2018. Led by Sourabh Paul, a Research Associate at the University of Manchester, the study appeared in The Astrophysical Journal Letters.
“What is especially impressive is that the data was obtained nearly a decade ago when MeerKAT had just commenced science operations.”
Sourabh Paul, Research Associate at the University of Manchester, via Universetoday
The team successfully isolated the 21-centimeter line of neutral hydrogen at redshifts of roughly z = 0.32 and 0.44. These measurements correspond to distances of 3.67 and 4.76 billion light-years, meaning the detected hydrogen existed when the universe was approximately 10 and 9 billion years old.
Hydrogen Intensity Mapping Breaks New Ground
Instead of resolving individual galaxies optically, the team employed Hydrogen Intensity Mapping, a technique that measures the combined radio emissions of vast galactic populations. As the universe expands, the wavelength of the neutral hydrogen signal lengthens, permitting researchers to probe different epochs of cosmic history.
“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.”
Sourabh Paul, Research Associate at the University of Manchester, via Universetoday
Co-author Professor Laura Wolz noted that extracting the signal from observations not originally designed for hydrogen intensity mapping demonstrates the extraordinary scientific value of MeerKAT data. This milestone points directly toward future large-scale surveys with the Square Kilometer Array Observatory, which will integrate data from South African instruments and Western Australia’s Murchison Radio-astronomy Observatory.
Super-Kamiokande Detects Diffuse Supernova Neutrino Background
While radio telescopes listened for hydrogen whispers, another team of physicists reported spotting the ghostly traces of dead stars. Neutrinos are nearly mass-less, chargeless particles that pass through ordinary matter almost without interacting. Around 100 trillion neutrinos stream through a human body every second, leaving virtually no trace behind.
Researchers analyzing nearly 14 years of data from the Super-Kamiokande detector—situated 3,280 feet underground in Gifu Prefecture, Japan—announced the first indication of a neutrino flux known as the Diffuse Supernova Neutrino Background. The findings were presented on June 25, 2026, at the XXXII International Conference on Neutrino Physics and Astrophysics held in Irvine, California.
“Observing the world’s first indication of the Diffuse Supernova Neutrino Background is a deeply meaningful achievement and has been a long-cherished goal since the beginning of the Super-Kamiokande project.”
Hiroyuki Sekiya, University of Tokyo, via Space.com
Connecting Ghost Particles to Stellar Collapses
The detected neutrino background originates from core-collapse supernovas, which occur when massive stars exhaust their nuclear fuel and can no longer generate the outward energy required to balance gravity. The stellar core collapses into a neutron star or black hole, releasing intense shockwaves and floods of neutrinos.
By examining Cherenkov light generated when these elusive particles interact with 50,000 tons of ultrapure water inside Super-Kamiokande, researchers detected the faint accumulation of neutrinos generated by billions of past stellar deaths across cosmic history.
“We are already planning on incorporating ongoing observations at Super-Kamiokande together with its successor detector, Hyper-Kamiokande, to further improve sensitivity in future collaborative studies.”
Yosuke Ashida, Tohoku University, via Space.com
