Within the cave’s cool confines in 1980, a local monk happened on something unexpected: a jaw with two huge teeth that, while human, was definitely not like that of humans today. A detailed analysis of its physical features as well as proteins extracted from the fossil suggest that the mandible, dated to 160,000 years ago, comes from the enigmatic human population known as the Denisovans—a sister group to the Neanderthals previously identified from scant remains found in a single cave in Siberia’s Altai Mountains. A study published earlier this year suggested that what we call Denisovans might actually be three distinct genetic lines, one of which is nearly as different from other Denisovans as they are from Neanderthals But the similarity of proteins across groups and through generations makes it difficult to pinpoint precisely how similar the owner of the jaw is to these three Denisovan lines—or if it was from yet another sister group.

“This is the first impact flash unambiguously recorded on the Moon during a lunar eclipse and discussed in the scientific literature,” the authors write. The night of the lunar eclipse in early 2019 did not coincide with any major meteor showers on Earth, and based upon their analysis, the Spanish scientists said they are 99 percent sure the impact was associated with a random or “sporadic” meteoroid—the same kind of meteors that people on Earth see in the night sky when there are no active meteor showers. These impacts can be fairly bright because the Moon lacks an atmosphere, and so some strikes hit the lunar surface traveling as fast as 30km/s, releasing a flash of light and heat that can be seen from Earth.