Life needs more than water alone. Recent discoveries suggest that plate tectonics has played a critical role in nourishing life on Earth. The findings carry major consequences for the search for life elsewhere in the universe.

Quote Originally Posted by Quanta Magazine
From a distance, it’s not obvious that Earth is full of life. You have to get pretty close to see the biggest forests, and closer still to see the work of humans, let alone microbes. But even from space, the planet itself seems alive. Its landmass is broken apart into seven continents, which are separated by vast waters. Below those oceans, in the unseen depths of our planet, things are even livelier. The Earth is chewing itself up, melting itself down, and making itself anew.

A dozen cold, rigid plates slowly slip and slide atop Earth’s hot inner mantle, diving beneath one another and occasionally colliding. This process of plate tectonics is one of Earth’s defining characteristics. Humans mostly experience it through earthquakes and, more rarely, volcanoes. The lava currently spurting from backyards in Hawaii — a result of a deep-mantle hot spot — is related to tectonic activity.

But there’s more to plate tectonics than earthquakes and eruptions. A wave of new research is increasingly hinting that Earth’s external motions may be vital to its other defining feature: life. That Earth has a moving, morphing outer crust may be the main reason why Earth is so vibrant, and why no other planet can match its abundance.

“Understanding plate tectonics is a major key to understanding our own planet and its habitability. How do you make a habitable planet, and then sustain life on it for billions of years?” said Katharine Huntington, a geologist at the University of Washington. “Plate tectonics is what modulates our atmosphere at the longest timescales. You need that to be able to keep water here, to keep it warm, to keep life chugging along.”