On May 13, 2015, Prof. Eric Priest from St. Andrews University gave a lecture at NAOC about how astronomers' understanding of the Sun has changed since the 1960s, the time spanning his career as a researcher. Prof. Priest is a world-renown expert in solar astrophysics and is the recipient of many prestigious awards, including the Gold Medal of the Royal Astronomical Society. Prof. Priest started by introducing aspects of the history of St. Andrews University, including a description of James Gregory, who was also a professor at St. Andrews University in the 1600s and one of the founders of Calculus. He described some of James Gregory's contributions to science, including the Gregorian telescope and the first documented experiments with a diffraction grating, which arose from Gregory shining light through the feather of a bird. Prof. Priest then continued on to the main part of his talk, where he showed a photo of a total solar eclipse that was taken in 1966. He said that at that time, astronomers could only see one image of the solar corona per year, during a total solar eclipse, but now with satellites, astronomers can continuously monitor the solar corona. He also commented on how much models of the Sun have changed since his first visit to Beijing in 1983. Prof. Priest continued by describing how our understanding of different aspects of the Sun have advanced, including models that incorporate magnetohydrodynamics, magnetic fields in the photosphere, and temperature transport in the interior, as well as sunspots, filaments and the solar wind. He showed results from sophisticated numerical simulations and high-resolution observations that have contributed to advancements in solar astrophysics. He also mentioned that, a few days previously, he visited the New Vacuum Solar Telescope in Kunming, which is part of Yunnan Observatories, and described how this facility is producing a wealth of observations that monitor solar activity. Prof. Priest ended his talk by saying human curiosity drives progress in science and students should stay curious during and after their studies.