Ancient rocks from the Earth's crust are being used as 'time capsules' to catch dark matter that passed through them billions of years ago.
April 15, 2026
Original Paper
Toward Neutrino and Dark Matter Detection with Ancient Minerals: TEM Study of Heavy-Ion Tracks in Olivine
arXiv · 2604.09732
The Takeaway
Normally, searching for dark matter requires building massive, multi-million dollar detectors deep underground. This paper proposes that we don't need to build them; the Earth already did. They discovered that ancient minerals like olivine preserve tiny, nanometer-sized 'scars' from when subatomic particles like neutrinos or dark matter crashed into them eons ago. By using high-powered microscopes to look at these 'heavy-ion tracks,' scientists can turn a simple rock into a 2-billion-year-old particle detector. It’s a genius hack that allows us to look back through the history of our galaxy to see how much dark matter was flying around before humans even existed.
From the abstract
Solar, supernova, and atmospheric neutrinos, and possibly weakly interacting massive particle (WIMP) dark matter, have been interacting in the Earth beneath our feet for billions of years. The ''paleo-detector'' technique seeks to detect and characterize the induced crystalline defects from these events, in particular from energetic nuclear recoils, which in some minerals can be preserved on these timescales. Such defects can manifest as nuclear recoil tracks, on the order of a few nanometers wi