French anthropologists Griaule and Dieterlen, working 1931-1956, reported Dogon lore: Sirius's invisible companion Po Tolo, a 50-year elliptical orbit, extreme density, a metal not on Earth, plus Jupiter's four moons and Saturn's ring. Robert Temple's 1976 Sirius Mystery made it the pillar of ancient-astronaut literature: the amphibious Nommo taught them. The check came in 1991: Walter van Beek's restudy found no Dogon outside Griaule's informant circle had heard of Sigu tolo or Po Tolo, informants disagreed completely on which star was meant, and several said they learned about the star from Griaule. The data trace to one man, Ogotemmeli, the blind hunter.
Sagan's Broca's Brain noted the knowledge was anachronistically incomplete, aliens would have mentioned Uranus and the larger solar system, and skeptics pointed to transmission: an 1893 French eclipse expedition spent five weeks in Dogon country, and Sirius B was public astronomy by the 1930s. Van Beek's informants said the quiet part aloud: they learned about it from Griaule, meaning the anthropologists may have imported the mystery they reported discovering.
The claim: the Dogon case is anthropology's loudest cautionary tale, the ethnographer found cosmic knowledge in a remote tribe precisely where a cosmic-minded ethnographer was asking, and the tribe politely supplied a mirror; the real mystery is why the West needed its aliens to be teachers. Verdict: van Beek documented the mirror mechanism. The archive files it beside every contact narrative in the collection: the visitor from the stars who arrives knowing exactly what the visitor from the university wanted to hear.
If the knowledge came from aliens, why is it unavailable from anyone else in the tribe?