Sign up for the free Nautilus newsletter for beautiful writing on science and culture. The eerie experience of walking alone in the night forest can be chilling, especially the mysterious sounds you can’t identify. While loud cracking sounds attributed to trees have long been explained by freezing sap, acoustics professor Unto Laine discovered a surprising alternative source in the night sky. Through extensive research, Laine found that the noises are actually produced by the inversion layer of warm air that traps ions and discharges energy. The groundbreaking findings bridge atmospheric science and acoustics, although further evaluation is needed. The spooky noises in the night sky reveal a fascinating twist to the nature of auroral sounds.
https://nautil.us/how-the-night-sky-speaks-to-us-772258/