Earlier this month, Professor Aninda Sinha of the Indian Institute of Science, Bengaluru, and his former student Faizan Bhat discovered a surprising link between the mathematics of Srinivasa Ramanujan and physics. They connected Ramanujan’s special formulas for pi to the physics of turbulent fluids and the expanding universe. Their findings were published in Physical Review Letters. Pi (π) is the famous ratio of a circle’s circumference to its diameter. It is an irrational number with endless digits after the decimal. Ramanujan, over a century ago, found fast formulas to calculate 1/π, which are still used in modern supercomputers. But Dr. Sinha’s interest was not just in computing pi. He wanted to understand the deeper math behind Ramanujan’s work. The journey started in string theory, where tiny energy loops called strings describe fundamental particles. Studying string theory, Dr. Sinha found new formulas for pi—actually an infinite number of them. He said, “If π is somehow hidden in the string answer, it should have an infinite number of different ways of looking at it.” This led him to revisit Ramanujan’s formulas. He noticed the math matched the patterns found in something called conformal field theories (CFTs). CFTs explain critical points in physics, like when water becomes superfluid and the boundary between liquid and gas disappears. Dr. Sinha explained, “At the critical point, you cannot actually say which is liquid and which is vapour.” The math in Ramanujan’s pi formulas closely resembles the math used in CFTs, especially logarithmic ones. Currently, their work does not solve big problems in number theory or cosmology. But it forms an exciting bridge between Ramanujan’s modular equations and modern physics. Faizan Bhat said, “Ramanujan’s motivation might have been very mathematical, but without his knowledge, he was also studying black holes, turbulence, percolation, all sorts of things.” Dr. Sinha gave examples of pure math later explaining real physics. For example, Riemannian geometry became key in Einstein’s theory of relativity. Joseph Fourier’s math on heat led to digital images and music compression. This Ramanujan-CFT link has opened a new research path. Dr. Sinha’s team found that similar math structures appear in models of an expanding universe. They also believe other special numbers like pi might have physics-based formulas like those found here. This discovery shines a light on the deep, hidden connections between ancient math and the universe’s secrets.