M.B.Rajani is Associate Professor at the National Institute of Advanced Studies (NIAS), Bangalore. Her research has two inter-related facets: analysing cultural landscapes using geospatial data to identify new features of archaeological interest and advancing the usage of such analysis towards preservation of built heritage in the face of rapid urbanization. Her primary scientific contribution has been to develop a methodology for detecting tell-tale signs of past human activities on landscapes from satellite imagery and integrating these findings with other spatial data to generate new inferences and novel hypotheses about the past. Her work has therefore expanded the field of archaeology to include the study of human impact on landscapes. Her recent book Patterns in Past Settlements (2021) aims at imparting this knowledge to larger research and academic communities. She was a member of Indian National Young Academy of Science 2018-2022, a Young Affiliate 2019-2023 of The World Academy of Sciences and recipient of Rachapudi Kamakshi Memorial Young Geospatial Scientist Award 2011 and P.R. Pisharoty Memorial award 2019 awarded by the Indian Society of Remote Sensing.

Abstract of the lecture

Five Degrees of Variation at Nalanda: a stellar hypothesis

Historical records suggest that Nalanda was a Buddhist monastery of considerable repute, which remained in existence from the 4th/5th century CE until at least the end of the 12th century CE. Phased excavations conducted by Archaeological Survey of India (between 1863 and 1983) have exposed sixteen large structures: six temples (chaitya) and ten monasteries. This talk will focus on the curious variation in the east-west orientations of these six temples, which vary in a narrow band about five degrees wide. The historical record does not suggest any explanation for this mysterious five-degree variation. By measuring temple orientations using satellite imagery, we identify an interesting pattern that could serve as an important clue: older constructions are generally aligned closer to the cardinal directions than newer constructions. Based on this pattern, we present a novel hypothesis: these temples were oriented to the rise of a particular star. If true, not only does this hypothesis explain the five-degree variation as a consequence of axial precession (a well-understood astronomical phenomenon), but it allows us to estimate an approximate date of construction for each temple based only on its orientation.