Astronomy Picture of the Day—20190129

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2019 January 29

MoonStruck

ImageCredit & Copyright: Petr Horálek

Explanation:Craters produced by ancient impacts on the airless Moon have long been afamiliar sight. But only since the 1990s have observers began to regularlyrecord and study optical flashes on the lunar surface, likely explosionsresulting from impacting meteoroids. Of course, the flashes are difficult tosee against a bright, sunlit lunar surface. But during the January 21 totaleclipse many imagers serendipitously captured a meteoroid impact flash againstthe dim red Moon. Found while examining images taken shortly before the totaleclipse phase began, the flash is indicated in the inset above, near the Moon'sdarkened western limb. Estimates based on the flash duration recorded by theMoon Impact Detection and Analysis System (MIDAS) telescopes in southern Spainindicate the impactor's mass was about 10 kilograms and created a craterbetween seven and ten meters in diameter.