Blurs

In October 1991, something extraordinary slammed into Earth's atmosphere. It wasn't an asteroid, a comet, or a burst of solar radiation. It was a single subatomic particle carrying more energy than physicists believed Nature should be able to produce.  More than three decades later, scientists still cannot say with certainty where it came from.  The event has become one of the greatest unsolved mysteries in modern astronomy—and it all began with a detector quietly watching the skies over the Utah desert. A Visitor from the Edge of the Impossible Every second, billions of tiny particles pass through your body without leaving a trace.  These particles, known as cosmic rays, arrive from every corner of the universe. Most are harmless and possess relatively modest energies. They originate from the Sun, exploding stars, or distant galaxies, continually bombarding Earth without attracting much attention. Then there are the exceptions. On 15 October 1991, an observatory known as...