Mysterious Monopole Remains Elusive

New search for hypothetical particle focuses on old rocks where monopole abundance should be higher.

The magnetic monopole is the Yeti of the subatomic world—avidly sought but never incontrovertibly seen. Reporting in Physical Review Letters, a team of physicists argues that old, high-latitude rocks derived from the Earth’s interior should be prime hunting ground for the hypothetical particles. Although the team’s search came up empty, their strategy may offer a way to set stronger limits on the abundance of monopoles within the planet.