A handful of incredibly rare solar neutrino events were detected turning carbon-13 into nitrogen-13 deep underground.

The finding confirms a long-anticipated reaction and provides a new tool for probing the universe’s smallest and strangest particles.

Ghost Particles and a New Kind of Interaction
Neutrinos rank among the most puzzling particles known to science. Often described as ‘ghost particles’, they almost never interact with ordinary matter. Trillions move through each of us every second without leaving any trace behind. These particles emerge from nuclear processes, including those happening at the heart of our Sun, yet they are extremely difficult to detect because they so rarely collide with anything.

Until now, solar neutrinos have only been observed interacting with a limited number of materials. Researchers have now achieved a first: they have documented neutrinos converting carbon atoms into nitrogen inside a massive underground detector.