Every eleven years, the sun’s magnetic field flips. Sunspots—dark, cooler regions on the sun’s surface that mark intense magnetic activity and often trigger solar eruptions—appear at mid-latitudes and migrate toward the star’s equator in a butterfly-shape pattern before fading as the cycle resets. While this spectacle on the star’s surface has long been visible to astronomers, where this powerful cycle begins inside the star has remained hidden until now.

Researchers at the New Jersey Institute of Technology (NJIT) have analyzed nearly three decades of solar oscillation data to trace the sun’s interior dynamics, and have now pointed to the likely location of the star’s magnetic engine deep beneath its surface: roughly 200,000 kilometers down, about the length of stacking 16 Earths end to end.

The findings, published in Scientific Reports, provide one of the clearest observational windows yet into the sun’s magnetic engine—the solar dynamo—shedding light on hidden forces shaping space weather patterns linked to the solar cycle, not only on Earth’s nearest star, but potentially on other stars across the galaxy.