Unicorns, Bigfoot, and banshees have been scientifically debunked, but ghosts are real – kind of. The exceptionally elusive neutrinos and their counterpart antineutrinos are known as ghost particles because they almost never interact with matter, due to their lack of electric charge and near-nonexistent mass. Yet these phantasmal fundamental particles can help improve nuclear safeguards by providing a non-intrusive way to examine the goings-on inside nuclear reactors – including the spectral flux of antineutrinos after a power plant has been switched off. In a recent breakthrough, physicists measured this residual emission for the first time, detecting the dim, eerie glow of electron antineutrinos emanating from the darkness of slumbering nuclear reactor cores in France. Led by physicists from the Max Planck Institute for Nuclear Physics (MPIK), researchers from the Double Chooz Collaboration have experimentally validated this predicted flux, emanating from burnt fuel inside two reactors as well as the removed waste material placed in cooling pools.