May 13, 2021
Scientists call it a “diffuse auroral eraser.” That’s because this newly named aurora first appears as a bright stripe over a diffuse auroral background. Then, when it disappears, it scrubs out the faint auroral light behind it.
Scientists at the University of Iowa said on May 6, 2021, that they’ve given the name
diffuse auroral eraser to a new type of aurora not often seen and not well understood. This new and elusive type of aurora – noticed in a 19-year-old video made by a physicist – has never before been described in scientific literature. The new name
diffuse auroral eraser describes how this sort of aurora first appears as a brighter stripe within a fainter, more diffuse aurora. When the stripe disappears, it blots out the diffuse light from the background aurora, as though the aurora is erased from that specific patch of sky. Then, after about 20 seconds, the diffuse background aurora reappears.