Plate Nº 96 · recorded October 10, 2026
Space & AstronomyReported finding
CHIME Telescope Detects Cosmic Hydrogen Glow, Opening New Path to Dark Energy
CHIME detected hydrogen's faint radio glow from when the universe was 5 billion years old using only its own data, opening a cheaper, independent way to study dark energy.
By Elena Vasquez3 min read695 words
In brief
- CHIME detected hydrogen's radio glow from when the universe was about 5 billion years old, using its own data alone.
- The detection is based on 94 nights of observations collected in 2019.
- The team spent over a year verifying the signal before publishing in The Astrophysical Journal (2026).
- Roughly 2% of hydrogen in the universe was in neutral atomic form at that time.
- Nearly seven years of CHIME data remain available, with plans to reach an epoch when the universe was 3 billion years old.
A Canadian radio telescope has, for the first time, detected the faint radio glow of hydrogen gas from roughly 5 billion years ago using only its own data. The Canadian Hydrogen Intensity Mapping Experiment (CHIME) near Penticton, British Columbia, achieved the milestone after analyzing 94 nights of observations collected in 2019. Two papers describing the work appear in The Astrophysical Journal (2026).
The result matters because dark energy—the mysterious force thought to be pushing the universe to expand ever faster—remains one of the biggest open questions in physics. Astophysicists hold conflicting theories about its nature. CHIME's independent measurements can now help prove or disprove them.
"Hydrogen is the most common element in the universe and the raw material from which stars form," said co-author Dr. Arnab Chakraborty, a postdoctoral fellow at the University of Toronto who first proposed the finding. "Its faint radio emission acts like a cosmic tracer, revealing how matter is distributed across space."
What makes this detection different?
CHIME maps the entire northern sky every day. It was built specifically to chart hydrogen gas in the early universe, letting astronomers calculate cosmic expansion and probe dark energy.
Until now, the telescope had to combine its measurements with galaxy survey data from other instruments. Those surveys study galaxies in fine detail using light, but they cost millions of dollars more and only cover regions hot and dense enough to form stars.
By mapping the combined radio glow that hydrogen emits on its own, CHIME can explore the same questions:
- on a greater scale,
- further back in time,
- at a fraction of the cost,
- without depending on anyone else's results.
"This is a completely new technique for probing the cosmos, delivered by an instrument that was conceived, built by Canadians," said co-author Dr. Mark Halpern, a professor at the University of British Columbia and CHIME principal investigator. "It's a bold new step in the global cosmology program and a Canadian success story."
What does the signal say?
In an accompanying paper, the team examined what the detection reveals about how hydrogen is spread through the universe.
"Our data indicate that roughly 2% of the hydrogen in the universe was in neutral atomic form at this time, broadly consistent with other measurements," said co-author Dr. Shabbir Shaikh, a postdoctoral fellow at Arizona State University. "By measuring how that hydrogen is distributed and clustered, CHIME gives us a new way to test our understanding of how galaxies form and evolve."
The neutral atomic form means hydrogen atoms holding their electron intact—as opposed to ionized hydrogen, where the electron has been stripped away. Radio waves at the 21-centimeter wavelength reveal this cold, neutral gas, which optical telescopes cannot see directly.
How did the team rule out a false alarm?
The discovery was no eureka moment. The signal sits amid overwhelming noise from the background universe, human technology, and the instrument itself. Researchers developed new data analysis and processing techniques to extract it, then spent more than a year testing whether it genuinely came from the era when the universe was about 5 billion years old.
"We worked very hard to convince ourselves that this wasn't a false alarm," Chakraborty said. "After all the tests, the signal remained. That gave us confidence we were seeing real hydrogen from the distant universe."
What comes next?
The current measurement uses only a small fraction of CHIME's total archive. The team now has nearly seven years of observations and plans to extend the analysis to earlier cosmic epochs, when the universe was just 3 billion years old.
"By actually showing that the technique works in practice, we've opened up a whole new window on the universe," said co-author Dr. Simon Foreman, an assistant professor at Arizona State University. "We can use it to test our current theories, and learn new things about galaxies and other properties of the universe."
CHIME is a pan-Canadian project operated by scientists at UBC, McGill University, the University of Toronto, and the Dominion Radio Astrophysical Observatory, with collaborators including Arizona State University. The National Research Council of Canada hosts the telescope.
via Phys.org Space & Astronomy (Source)
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