In 2022, NASA engineers in Pasadena watched a new image come down from Perseverance and saw a small heap of broken rocks resting on the Martian surface in a pattern that looked almost intentional, and the explanation they eventually offered involved a vanished river that has not flowed in three billion years. (opens in new tab)

Perseverance landed in Jezero Crater on February 18, 2021, in a basin that scientists believe held a lake roughly 3.5 billion years ago, and almost everything the rover has photographed since then is haunted by water that is no longer there. The crater floor is dry. The river that fed it is gone. What remains […]