The characteristic period of the Sun’s p-mode oscillations is about 5 minutes.
P-modes are pressure modes: acoustic waves in which pressure acts as the restoring force. They form resonant patterns inside the Sun, causing portions of the visible surface to move slightly inward and outward. The observed oscillations are not one perfectly uniform pulse; the Sun vibrates in a superposition of many modes with different frequencies, depths, and surface patterns. Five minutes is the characteristic timescale of the strongest commonly discussed solar oscillations.
The phenomenon was first observed in the early 1960s by Robert Leighton, Robert Noyes, and George Simon. It was initially thought to be a local disturbance connected with convection. Later work showed that the oscillations are global resonant waves, creating the foundation of helioseismology—the study of the Sun’s interior through its surface vibrations.
By measuring tiny Doppler shifts and brightness changes, researchers infer properties such as sound speed, rotation, and internal structure. The term “five-minute oscillations” is a useful shorthand, not a claim that every p-mode has exactly the same period; many detectable modes span nearby periods.