Intro from the Queen's Gazette article What is the Earth made of?
If we can’t drill our way to the centre of the Earth, how do we know what’s there? Scientists investigate phenomena that can be observed from the surface: earthquakes, erupting volcanoes, and lab experiments that put minerals under extreme pressure are a few examples. Now, for the first time in Canada, a new hint into the planet’s interior is being explored: geoneutrinos, small subatomic particles that came from the Earth’s very core.
Geoneutrinos are a type of antineutrino produced by radioactive decays happening inside the Earth. By measuring geoneutrinos, we can measure the chemical composition of the planet.
–Prof. Alex Wright