Astronomers are saying it might be the first known event of its kind, a flash of light seen during a total lunar eclipse. The eclipse took place during the night of January 20-21, 2019, and many caught it on film (see photos). But some sharp-eyed photographers and livestream viewers also noticed a flash on one edge of the moon, as a rock from space struck the surface of Earth’s companion world, just as the total eclipse was beginning.

Flashes on the moon have been reported before, but never on a moon in eclipse, to our knowledge. The flashes tend to be faint and short lived, and, when one occurs, astronomers want to check to be sure the flash isn’t from a camera, and not the moon itself. In this case, many images showed the same thing, a flash south of the crater Byrgiu – on the western part of the moon – at 4:41 UTC.