Alternate timeline
(covers information from an alternate timeline)
Polaric radiation is a form of radiation caused by proximity to polaric ions which can interfere with sensors.
In 2371, the USS Voyager encountered a planet that had been devastated by a polaric ion explosion. Kathryn Janeway and Tom Paris were exposed to polaric radiation while investigating the surface. After they were transported backwards in time to before the explosion by a "fracture in time", Pe'Nar Makull detected the radiation was five times higher than normal. Because of this, he believed they were either government spies from the power plant, or were at the site of a polaric disaster worse than any in the history of the planet. (VOY: "Time and Again")