The jury is still out about how life first formed on Earth, but nailing down when the planet’s continental crust first formed will be key to figuring out the planet’s earliest days. An artist’s conception of the early Earth, showing a surface bombarded by large impacts that result in the extrusion of magma onto the surface. At the same time, distal portions of the planet’s surface may have retained liquid water. (Credit: Simone Marchi/SwRI) (CN) — Don’t let their quiet modesty fool you: rocks have a lot to tell. You just need to know where to look and what to ask them.