Clemson astrophysicist Marco Ajello was part of a team that located the source of a high-energy subatomic particle that pierced Earth. The neutrino traveled 3.7 billion light years (each light year is equivalent to about 5.88 trillion miles) at almost the speed of light before it passed through the crust of Antarctica on September 22, 2017, and interacted with a nucleus in the ice. The neutrino — the smallest known particle that contains mass — was produced by protons accelerated in a jet that was fueled by a supermassive black hole. For the other end of the spectrum, see “macro.”