It’s been a decade since the United States began fighting irregular wars that require protecting civilians in order to have a shot at success. Yet only now is the U.S. Army, alone among the military services, taking steps to redress an institutional shortcoming: giving its officers a practical guide to keeping civilians safe while waging war.

Danger Room has learned that an official with the Army’s Peacekeeping and Stability Operations Institute, Dwight Raymond, is drafting a manual on preventing civilian casualties. The manual, formally known as Army Tactics Techniques and Procedures 3-37.11, ...

The surface of Earth is being reshaped constantly. Mountainous uplands are broken down by water and wind producing sediment that is moved by rivers to lowlands. Some of this sediment is deposited along the way, some is delivered to the coast and continental shelf, and some makes its way to the ultimate sink, the deep sea. This transfer of material across the Earth’s surface creates the landscapes we inhabit.

However, the reshaping of the planet’s surface varies geographically and varies through time. How long does it take for sediment to be eroded from mountains? How long does it take for t...