The Ishango bone is a tool and possible mathematical device from prehistoric times. Its name is taken from the area of Ishango in the Democratic Republic of Congo where it was found.
[…] The bone, probably a fibula of a baboon, large cat, or other large mammal, has been dated to the Upper Paleolithic Period of human history, approximately 20,000-25,000 years ago. It is 10 cm long and bears an articulated, organized series of notches readily identifying it, to many observers, as a tally stick. However, its original purpose remains a subject of debate. The Ishango Bone is now housed at the Museum of Natural Sciences in Brussels, Belgium, with whose cooperation the image above was obtained.
Is it a tally stick? Is it the oldest table of prime numbers? Or is it a calendar?
Alexander Marschak, an independent scholar, argued that it represents a six-month lunar calendar. In 1970 Marshack published his innovative Notation dans les gravures du Paléolithique Supérieur. He argued that talley marks on certain bones represented a system of proto-writing, and proposed the controversial theory that notches and lines carved on certain Upper Paleolithic bone plaques were notation systems, specifically lunar calendars notating the passage of time. Using microscopic analysis, Marshack showed that seemingly random or meaningless notches on bone were sometimes interpretable as structured series of numbers. Marshack expanded upon these ideas in his book, The Roots of Civilization (1972). If Marshack’s interpretation is correct, notched bones such as these may be, in the words of John Eccles, the earliest “conceptual performance of homo sapiens.” Alternatively they may be a yet to be understood method of recording information, or something else.
Whatever it is, or was, it wasn’t made by aliens.