The European Space Agency (ESA) recently posted footage of the pair of flashes that occurred on July 17 and July 18. Although the flashes were detected from Earth, the original meteoroids — fragments of the midsummer Alpha Capricornids meteor shower — were probably each only the size of a walnut, researchers said.
The moon received these lumps from space while passing through the dusty tail of Comet 169P/NEAT, the ESA said in a statement released with the footage.
"For at least a thousand years, people have claimed to witness short-lived phenomena occurring on the face of the moon," ESA officials said in the statement. "By definition, these transient flashes are hard to study, and determining their cause remains a challenge.
"For this reason, scientists are studying these 'transient lunar phenomena' with great interest, not only for what they can tell us about the moon and its history, but also [for what they can tell us] about Earth and its future," the officials added.
The new images come courtesy of the Moon Impacts Detection and Analysis System (MIDAS), which is installed on three observatories across Spain. The system is endowed with high-resolution CCD video cameras designed to pick up these subtle flashes of light. It's even easier to spot these flashes if they happen during full lunar eclipses, such as the one that just occurred on July 27.
Researchers said that while the flashes are interesting in and of themselves, the events also help us learn more about meteorite impacts on other locations in the solar system.
"By studying meteoroids on the moon, we can determine how many rocks impact it and how often, and from this we can infer the chance of impacts on Earth," Jose Maria Madiedo, a member of MIDAS and a meteorite researcher at the University of Huelva in Spain, said in the statement.