The Sun is just one of a hundred billion stars in the Milky Way galaxy. Our front-row seat on Earth allows us to observe it in much greater detail than we can for other stars. However, those observations provide only one snapshot in the life story of stars like the Sun. To piece together the entire tale, astronomers need to study other stars that are younger and older. Their observations have revealed something unexpected that never could have come to light from studies of our Sun in isolation.
Almost half a century ago, astrophysicist Andrew Skumanich noticed that rotation and magnetism in stars are intricately linked. Based on observations of the Sun and a few young star clusters for which stellar ages could be estimated, he proposed that both the rotation rate and the magnetic field strength in stars are inversely proportional to the square root of age.
During a...
