This building is on Route 50 at the western edge of Delta, Utah. It may not look like it, but it’s an important building.
It is the headquarters of the Telescope Array project, a collaboration of researchers from the U.S., Japan, Korea, Russia, and Belgium, formed to study the impact of cosmic rays on the earth’s atmosphere.
“Cosmic rays” are not rays at all, but particles that were once part of an atom. The Millard Cosmic Ray Center detects a specific type of particle, called an “ultra-high-energy cosmic ray,” thought to be the nucleus of an iron atom. These particles have traveled at very high speed to arrive at our planet from up to 160 million light years away. They are extremely rare — a similar cosmic ray installation in Argentina, observing over 1,100 square miles of the earth’s surface, detected the arrival of just one such particle every four weeks.
The project in Utah is the largest such observatory in the northern hemisphere. It has been collecting data since 2007 using detectors placed in the nearby desert. Some are positioned in a triangle roughly 19 miles on a side, while others are spread across an additional 300 square miles.
These instruments detect two manifestations of cosmic rays: very faint flashes caused when arriving particles hit gas atoms in the earth’s atmosphere, and also the result of such a collision — a cascade of other particles called an “air shower.”
Heading west out of Delta, Route 50 passes southeast of the research area.