An unusual optical phenomenon explains why the Titanic struck an iceberg and received no assistance from a nearby ship, according to new research by British historian Tim Maltin. Atmospheric conditions in the area that night were ripe for super refraction, Maltin found. This extraordinary bending of light causes miraging, which, he discovered, was recorded by several ships in the area. He says it also prevented the Titanic’s lookouts from seeing the iceberg in time and the freighter Californian from identifying the ocean liner and communicating with it. A 1992 British government investigation suggested that super refraction may have played a role in the disaster, but that possibility went unexplored until Maltin mined weather records, survivors’ testimony and long-forgotten ships’ logs. His findings—presented in his new book, A Very Deceiving Night, and the documentary film Titanic’s Final Mystery, premiering on the Smithsonian Channel at 8 p.m. on April 15—are distilled here:

1 of 6 1. Thermal Inversion The Titanic was sailing from Gulf Stream waters into the frigid Labrador Current, where the air column was cooling from the bottom up, creating a thermal inversion: layers of cold air below layers of warmer air. Extraordinarily high air pressure kept the air free of fog. 1 of 6