The Sturtian glaciation, the longest Snowball Earth event, lasted about 57 million years — almost as long as the age of mammals after the dinosaurs vanished — yet new research from Scottish rocks shows that during at least one brief “slushy” interval, seasons, solar cycles and even El Niño-like rhythms were still pulsing through the frozen planet.

The Sturtian glaciation, the longest Snowball Earth event, lasted about 57 million years — almost as long as the age of mammals after the dinosaurs vanished — yet new research from Scottish rocks shows that during at least one brief “slushy” interval, seasons, solar cycles and even El Niño-like rhythms were still pulsing through the frozen planet.

The Sturtian glaciation is difficult to hold in the mind because its scale is so out of proportion to human history. It began roughly 717 million years ago and lasted tens of millions of years, making it the longest of the Snowball Earth episodes. A commonly cited duration is about 57 million years, almost as long as the entire age of mammals since the asteroid impact ended the reign of the non-avian dinosaurs 66 million years ago. For that span…