A new eye in the sky is revealing monster lightning discharges, including a bolt that travelled more than 500 kilometres.

A lightning-mapping instrument aboard one of the newest US weather satellites has spotted record-breaking electrical flashes in the sky — including a behemoth lightning bolt more than 500 kilometres long that blazed above Oklahoma two years ago.

Walter Lyons at FMA Research in Fort Collins, Colorado, and his colleagues studied data from ground-based lightning detectors and an instrument aboard the GOES-16 spacecraft, which was launched in 2016. The researchers identified a lightning flash that travelled more than 500 kilometres — from Texas, across Oklahoma and into Kansas — in October 2017. It illuminated an area of 67,845 square kilometres.

This ‘megaflash’ dwarfs the official record for the longest lightning flash, a 321-kilometre-long bolt that was observed over Oklahoma in 2007. But records will continue to be broken thanks to data from the GOES-16 lightning mapper and a twin mapper on the GOES-17 satellite, which was launched in 2018. Other scientists have already spotted a 673-kilometre-long flash in GOES data..

Such extreme lightning might lead scientists to reconsider their understanding of how much electricity the atmosphere can generate.