Cosmic rays are streams of highly energetic particles arriving at the Earth from sources beyond the Milky Way galaxy. In this video, Gordon Thomson from the University of Utah in the US explains what this phenomenon can teach us about the nature of the cosmos. Specifically, Thomson introduces the Telescope Array experiment in Millard County, Utah, which observes the secondary radiation produced by cosmic rays interacting with particles in the Earth’s atmosphere. The experiment is being used to create a map of the sky to identify cosmic ray sources and investigate how they might be able to accelerate particles to such high energies.

This video is part of our 100 Second Science series, in which researchers give concise presentations covering the spectrum of physics.