A search for meteoritic flashes on the Moon

We present the first results of a search for bright flashes associated to i mpacts of meteoroids on the surface of the night side of the Moon. We have analysed 13 sets of images of a (2.9+/-0.3) 10(6)-km(2)-wide area on the Mo on's night side, totaling 4.3 h of observations. No impact events radiating an amount of energy higher than 5 x 10(6) J have been detected. Five faint er events (E < 2.5 x 10(6) J) have been detected, but they are not confiden tly identified as impact-related, and might be due to experimental problems . This rate of events would imply an influx of 4800 +/- 500 meteoroids per day onto the Earth, with meteoroid masses of uncertain value, but larger th an 0.01 kg. The direct CCD imaging technique that we have used is a potenti al new tool to asses the population of those meteoroids in the vicinity of the Earth whose masses and velocities are such that the radiated energy upo n impact is higher than 5 x 10(6) J, our threshold for 100% confident detec tion. The technique can be improved substantially to detect fainter impacts and might provide unique data for the 1999 Leonid meteor shower.