Between 2006 and 2014, a NASA balloon experiment floating above Antarctica picked up two bizarre radio signals coming up from beneath the ice at angles that should have been impossible — and more than a decade later, no physicist has been able to explain what the signals actually were, with some researchers suggesting they may have been caused by a particle currently unknown to science

Between 2006 and 2014, a NASA balloon experiment floating above Antarctica picked up two bizarre radio signals coming up from beneath the ice at angles that should have been impossible — and more than a decade later, no physicist has been able to explain what the signals actually were, with some researchers suggesting they may have been caused by a particle currently unknown to science

Twenty years ago, somewhere above the Antarctic ice, a balloon-borne radio antenna recorded an event that, by every available standard of contemporary physics, should not have happened. Eight years after that, it happened again. A particle — or something that behaved like a particle — appeared to have travelled directly upward through approximately 6,000 kilometres of solid Earth, carrying enough energy to register as a brief, bright burst of ra…