91av

There is something strange about Earth. A few billion years ago, a process started here that we have never seen anywhere else. It completely reshaped the planet’s surface and its carbon cycle, sculpted new landscapes and has kept our home temperate and habitable for billions of years.

That process is plate tectonics, in which Earth continuously subsumes and reforms the slabs of its rocky outer shell. It is thought to be inextricably linked to habitability and perhaps an essential prerequisite for life itself. Without it, our lakes and rivers might have frozen or evaporated, the oceans could have been starved…