On Christmas Day 2022, a extremely peculiar aurora was seen over an unlimited part of the Arctic sky, the likes of which have by no means beforehand been noticed from the bottom. Often called a polar rain aurora, this distinctive mild present was produced by a waterfall of electrons that emanated from the solar earlier than cascading peacefully over the North Pole.Usually, auroras encompass dynamic, shifting lights that change form and shade as they dance throughout the sky. This phenomenon is attributable to charged photo voltaic particles interacting with the Earth’s magnetic discipline, earlier than being channeled in the direction of the poles.Nonetheless, the spectacle noticed on the evening of December 25 2022 was fully totally different. For one factor, it was huge, masking an space of round 4,000 kilometers (2,500 miles). Extra curiously, although, it was fully uniform and unchanging, consisting of a clean, featureless inexperienced glow that simply hung within the sky with out morphing or rearranging itself into any shapes.To search out out what occurred, the authors of a brand new research examined information from the US Protection Division’s polar-orbiting satellites. In doing so, they found that the photo voltaic wind had dropped to just about zero on the time of the aurora, which additionally coincided with the opening of a so-called coronal gap on the solar’s floor.As a consequence, high-energy electrons had been in a position to stream out of this coronal gap with out turning into scattered by the photo voltaic wind. These particles – which might usually be blown from pillar to publish, creating fast-moving aurorae – had been due to this fact in a position to gently rain down over the North Pole in a gentle stream, creating a very flat aurora.“By combining ground-based and satellite tv for pc observations, we proved that this distinctive aurora was produced by suprathermal electrons streaming straight from the Solar, which is named “polar rain.”,” write the researchers. Till now, this phenomenon had solely ever been noticed from house, however had by no means been seen from the bottom.The research authors additionally calculated that the unfold of electrons streaming out of the coronal gap would have coated some 7,500 kilometers (4,600 miles) of the sky, which explains why this version of the Northern Lights was so massive.“This extremely clean and gigantic type is distinctively totally different from that of a typical polar cap aurora,” clarify the researchers. “Thus, it can’t be categorized as any beforehand recognized class of aurorae seen at polar cap latitudes.”The research has been printed within the journal Science Advances.