Environmental Science - Blog Posts

“Those who dwell, as scientists or laymen, among the beauties and mysteries of the earth are never alone or weary of life. Whatever the vexations or concerns of their personal lives, their thoughts can find paths that lead to inner contentment and to renewed excitement in living. Those who contemplate the beauty of the earth find reserves of strength that will endure as long as life lasts.”

— Rachel Carson, The Sense of Wonder

Physicists have finally figured out why these massive ice discs start spinning on their own

New physics from a 100-year-old mystery.

New physics doesn’t always come from the recesses of space or the bowels of the Large Hadron Collider. Sometimes, you just need some cameras, a nickel bead, a magnet, and Petri dish popsicles.

Every once in a while, someone notices a big disc of ice eerily spinning in a river. These discs can be anywhere from 1 to 200 metres across, and almost everything about them has mystified physicists and environmental scientists for over a century. While it’s thought that this rare natural phenomenon is likely was caused by cold, dense air coming in contact with an eddy in a river, no one’s been able to definitively explain why these giant discs continue to rotate as they melt. Until now.

The most common explanation for the spinning ice discs says that as the discs float along in a river, they’re spun around by eddies - little spinning currents that form when water flows over rocks or into an enclosed space. And while this is this is probably part of what’s happening, it can’t be the whole story.