Physicists hunting for elusive dark matter have turned the entire planet into a giant detector, analyzing a decade’s worth of data from the Earth-ionosphere cavity. According to theoretical physicist Atsushi Taruya, an author on four recent papers, the natural resonator amplifies electromagnetic waves right around the target mass range.
Using Earth as a Giant Dark Matter Detector
Visible matter across the cosmos does not account for the observed gravitational effects, leading scientists to suspect an invisible component dubbed dark matter. Because axions are predicted to interact with regular electromagnetic forces and decay into photons in strong magnetic fields, researchers checked ten years of data for signals within a narrow mass range. After filtering out background noise, the team identified 65 axion candidates, narrowing down to 25 after applying stricter statistical filters, according to the published findings.
Distinguishing Axions From Dark Photons
The detection technique also applies to dark photons, which are hypothesized force carriers that possess mass and interact with magnetic fields. Researchers uncovered up to 342 candidate signals using loose criteria, which reduced to 31 under a stringent signal-to-noise ratio, as detailed in Physical Review D. Because axion signals depend on Earth’s magnetic field while dark photons do not, scientists can test the particles by measuring signal strength globally. According to the research team, axion signals should weaken near the poles and peak around Southeast Asia, though current data sourced from a single UK observatory lacks that global perspective.
Probing Lower-Mass Particles With New Hardware
The device reached a sensitivity threshold of about one-tenth the mass of an electron, probing masses below one mega electron volt (MeV). The researchers equipped the device with superconducting microwires and a thin, planar geometry to pick up directional changes as Earth moves through a cosmic dark matter wind.
Did you know? While traditional detectors like liquid xenon systems struggle to spot particles lighter than an electron, newly optimized SNSPD devices and planetary-scale resonators are opening up entirely new mass ranges for physicists.
Frequently Asked Questions
What is dark matter?
Dark matter is an invisible form of matter that makes up about 80 percent of the universe’s mass, contributing gravitational effects without emitting or reflecting light.
How can Earth act as a dark matter detector?
According to physicists in Japan, the Earth-ionosphere cavity functions as a natural resonator that amplifies electromagnetic waves produced when axions or dark photons interact with magnetic fields.
What is the difference between axions and dark photons?
Axions depend on Earth’s magnetic field to generate their observable signal, whereas dark photons can produce signals with or without a magnetic field present.
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