Earth as a Detector: The Newest Front in the Dark Matter Search

For decades, the search for dark matter has been a story of ever-larger underground tanks and ever-colder crystals. But in 2025 and 2026, that story has taken several new turns. Researchers are now proposing to use the Earth itself as a detector, deploying superfluid helium cooled to near absolute zero, and pushing collider experiments to their limits. At the same time, the leading alternative theory to dark matter—Modified Newtonian Dynamics (MOND)—has faced some of its strongest observational challenges yet.

Using Earth as a Giant Dark Matter Detector

A collaborative team from Kyoto University, Hiroshima University, and Nihon University has proposed using the Earth itself as a giant detector for dark matter. The approach, published as a research news release on August 5, 2026, exploits the planet's immense volume to capture rare interactions from dark matter particles passing through the Earth . "We asked ourselves whether we could use the Earth itself as a giant detector in the search," says corresponding author Atsushi Taruya . The Earth-ionosphere cavity acts as a resonant structure that could amplify faint signals.

Separately, a team led by Atsushi Nishizawa (Hiroshima University) proposed searching for axion dark matter by monitoring ultra-low-frequency terrestrial magnetic field fluctuations, treating the Earth's natural magnetic environment as the detection medium . When axions with masses between 1×10⁻¹⁵ eV and 1×10⁻¹³ eV pass through the Earth, the theory predicts they would interact with the global geomagnetic field, generating detectable electromagnetic waves .

Japan is also leading on mineral-based detection. The third "Mineral Detection of Neutrinos and Dark Matter" (MDνDM'25) meeting was held in Yokohama in May 2025, hosted by JAMSTEC, focused on using mineral deposits as natural, long-exposure particle detectors .

The Status of MOND: The Leading Dark Matter Alternative Faces New Tests

Modified Newtonian Dynamics (MOND) proposes that gravity behaves differently at low accelerations, eliminating the need for invisible dark matter . It successfully predicts galaxy rotation curves, but recent evidence has significantly challenged it:

• A May 2026 study of Milky Way dynamics found the data strongly favors dark matter over modified gravity models (MOND and STVG), disfavoring MOND at >13σ and STVG at >4σ . This breaks previous degeneracies between baryonic structure and gravitational laws .
• A June 2026 re-analysis of the Bullet Cluster found observations could still be consistent with an alternative without dark matter, but if dark matter exists, it would likely be in smaller quantities than previously thought .
• A May 2025 review concluded MOND successfully explains galaxy rotation curves but fails on galaxy cluster scales . The most serious problem is that galaxy clusters show a residual mass discrepancy even when analyzed using MOND .
• A separate 2025 study using dwarf galaxies found that MOND predictions fail to reproduce observed behavior, while dark matter models naturally explain the data .

The prevailing scientific consensus remains that dark matter is favored over modified gravity as an explanation for the full range of cosmological and astrophysical data .

New Detector Projects: DELight in Heidelberg

In April 2026, the German Research Foundation (DFG) approved €5.3 million in funding for the DELight experiment—a direct search for light dark matter using superfluid helium-4 as the target material . The consortium is led by Heidelberg University, with partners at KIT (Karlsruhe) and the University of Freiburg .

DELight focuses on particles with very low mass as candidates for dark matter, explained Professor Kathrin Valerius . The detector uses ultra-cold superfluid helium instrumented with large-area magnetic microcalorimeters (LAMCALs), optimized to detect very low-mass dark matter particles that would produce tiny energy depositions . Helium offers several advantages: its low nuclear mass and intrinsic radiopurity make it ideal for low-threshold experiments, and it enables scalable detector designs .

The OMNIA research group at the Max Planck Institute for Nuclear Physics (MPIK) in Heidelberg is also active in dark matter searches through microlensing and astroparticle experiments .

CERN's FASER Experiment: Pushing the Boundaries of Dark Photon Searches

The FASER (Forward Search Experiment) at the Large Hadron Collider continues to produce results. In April 2026, it reported new searches for dark photons using 177 fb⁻¹ of proton-proton collision data from LHC Run 3 . Dark photons are hypothetical mediators of a hidden "dark sector" that could explain dark matter .

FASER's new search uses data collected between 2022 and 2024, corresponding to an integrated luminosity of 177 fb⁻¹ at a centre-of-mass energy of 13.6 TeV . The observed limit excludes dark photons with masses between about 10 and 150 MeV and couplings of around 10⁻⁵–10⁻⁴, ruling out part of the cosmologically viable parameter space . CERN's EP-News highlighted in June 2026 that FASER has opened new windows into both dark sectors and TeV-scale neutrino physics .

The Bigger Picture

The field is moving on multiple fronts—Earth-scale natural detectors (Japan), new dedicated cryogenic experiments (DELight in Heidelberg), collider-based dark sector searches (FASER at CERN), and continued tension between the dark matter paradigm and modified gravity alternatives. Direct detection has not yet found dark matter, but the sensitivity of experiments is improving rapidly . Next-generation detectors such as DarkSide-20k, DARWIN/XLZD, and PandaX-xT are in design, R&D, or construction phases .