On March 17 NASA detected the largest meteor impact on the Moon since they started watching for such impacts 8 years ago. This impact was observed as a brief flash of light as the meteor, estimated at 30-40cm (12-18 inches) across and travelling at 56,000 miles per hour, slammed into the lunar surface.
Here’s an informative short video from NASA which includes actual video of the impact, along with discussion of their monitoring program, interpretations of where this object came from and possible relevance of such impacts on future lunar missions.
Interestingly, they state that at certain times of the year, when the Earth-Moon system passes through meteor debris fields, lunar explorers might be best advised to stay indoors. One wonders, given that the energy released by this basket-ball sized object was equivalent to 5 tonnes of TNT, what kind of “indoors” they are thinking would protect their astronauts!
(Realistically, of course, the odds of getting hit on the head by such a thing, even in the midst of a meteor shower, are infinitesimal. Nonetheless, it is an interesting video.)