The Grand Canyon is one of the natural wonders of the world. Its mile-deep chasm slices through the heart of the American southwest, carrying the waters of North America’s seventh-largest river basin. Yet for most of its 300-mile length, the Grand Canyon is accessible only by
July 2026 marks the 250th anniversary of the American colonies’ Declaration of Independence from Great Britain. From a geological perspective, of course, two hundred and fifty years is merely the blink of an eye. Yet this particular quarter-millennium happens to include a geologically consequential explosion in human population and
A quarter of a mile from my office stands the Norlin Library. It is the University of Colorado Boulder’s main treasure trove of books, and the heart of its campus. The library is named for George Norlin (1871–1942), a professor of Greek language and literature who served as
On April 10, 1815, a mountain on the island of Sumbawa exploded. Mount Tambora, a fourteen thousand foot (3400 meter) peak at the Indonesian island’s north end, had begun stirring three years earlier, rumbling and spitting out clouds of ash. Somewhere below, pressure began to build, and on that
In the course of a project I’ve been working on, I’ve learned a bit about the life and times of various earth scientists of the 18th, 19th, and 20th centuries. It's been interesting to see how these scholars dealt with living in tumultuous times. Alexander von
During the week of the Thanksgiving holiday, I had the opportunity to visit a remote part of southeastern Utah near the Bears Ears National Monument. A striking feature of this landscape is a long hogback called Comb Ridge, or Tséyik’áán in Navajo. The ridge is formed from layers of
In a course I teach on geophysical fluid mechanics, I like show students a video depicting a year of weather on planet earth. The video looks down on a projected map of the world as viewed from space. Moisture rings the equator in a belt of clouds, riding ever westward
Last month I was invited to give a lecture on earth science to a group of 8th graders at a nearby middle school. I leaped at the chance. Although my day job is teaching university students, it’s not often I get to share science stories with kids at that
I’m enchanted by waterfalls, and not just for the obvious reasons. To a geologist, a waterfall is a slow-motion wave in solid rock. Occasionally you find waterfalls that are stationary, pinned in place by some hard piece of geology: an ancient dike of frozen lava, say, or a
On a hot afternoon this past July I paid a visit to Crawford Lake, a tiny dot of water 30 miles southwest of Toronto. Only 300 m long and about half as wide, the lake fills an ancient sinkhole that formed when the roof of an underlying cave collapsed. In
This month marks the 80th anniversary of a report that transformed American science and technology. In July 1945, Vannevar Bush delivered a report to President Harry Truman titled “Science: The Endless Frontier,” outlining a bold set of recommendations for future US science policy. The story of Bush’s vision and
June 15, 2025, marks the 34th anniversary of the eruption of Mount Pinatubo. In 1991, an unassuming peak fifty-four miles north of the Philippine capital of Manila blew its top, blasting more than a cubic mile of debris into the sky. Searing clouds of hot ash poured down its