CHIME Detects Ancient Hydrogen, Opening New Dark-Energy Probe
The Canadian Hydrogen Intensity Mapping Experiment, or CHIME, has for the first time detected faint radio emission from ancient hydrogen using only its own observations. This signal can trace how matter is distributed across space and help measure the universe's expansion, offering a new way to study dark energy. The results were published in The Astrophysical Journal.
CHIME, a radio telescope near Penticton, British Columbia, scans the entire northern sky daily. Its original design anticipated this kind of measurement, and the project involves Canadian institutions including UBC, McGill, Toronto, and the Dominion Radio Astrophysical Observatory, plus North American partners such as Arizona State University.
Previously, CHIME's team had to pair its radio data with galaxy surveys from other telescopes — costly efforts that mostly cover hot, dense regions where stars form. Detecting hydrogen's own emission lets researchers cover wider areas and look further back, at far lower expense.
Cheaper, independent measurements of cosmic expansion could broaden who participates in cosmology, letting smaller teams and institutions contribute without multimillion-dollar surveys. If the technique holds up, it may sharpen constraints on dark energy, though the payoff depends on follow-up work by other groups. For the public, the practical effects are likely indirect — improved maps of the universe may shape science education and long-term research funding priorities rather than daily life.