So how do you tell what's going on in the center of the Earth? Geologists have traditionally been limited to seismic studies, which definitely have their limitations. Now, however, it appears there's a new way to peer into the "down below". By using an exotic detector buried deep underground, a group of scientists have detected neutrinos, special sub-atomic particles, generated by the decay of radioactive materials in the Earth's core. Each "geoneutrino" carries a signature of its chemical origin, providing unique insights into the core's composition. While current detectors aren't sensitive enough to provide a lot of data, it's hoped now that the general concept has been proven that other, more sensitive devices can be created to provide more detailed observations.