Constraining Anisotropic Universe Through Big Bang Nucleosynthesis: A Case Study of The Bianchi Type-I Universe

The isotropy and homogeneity of our Universe are the cardinal principles of modern cosmology built on the definition of metric through the prescription by Friedmann-Lema$\hat{i}$tre-Robertson-Walker (FLRW). From the aspects of geometry, the presence of anisotropy, inhomogeneity, or both are allowed in the metrics defined as the Bianchi type I and V metrics. In this letter, the Big Bang Nucleosynthesis (BBN) formalism, and the latest observational constraints on nuclear abundances are being used to put bounds on the global anisotropy offered in the Bianchi type I metrics, providing a new path to explore in the background of global anisotropy.