Mark Garlick/Science Photo Library/Alamy
Something is wrong with Earth. Billions of years ago, a process unlike any other began here. It has completely reshaped the Earth’s surface and its carbon cycle, forming new landscapes and keeping our homeland warm and habitable for billions of years.
The process is plate tectonics, in which the Earth continually incorporates and reshapes slabs of its rocky outer shell. It is closely related to habitability and is probably considered an essential prerequisite for life itself. Without it, our lakes and rivers would freeze or evaporate, our oceans would lose nutrients, and Earth’s climate would likely have fallen into uninhabitable territory long ago. Life would have been difficult.
At least, that’s the idea. But given that we have nothing to compare it to, it’s hard to know whether plate tectonics is really important to Earth’s lush ecology. We know of no other planet that exhibits plate tectonics. Of the four rocky planets in our solar system, Earth is the only one that recycles its crust in this way, and no conclusive evidence has been found outside the solar system.
Until recently, this more or less ended the story. But now, with the help of the James Webb Space Telescope (JWST), scientists are beginning to explore the geology of rocky worlds outside our solar system. It is very difficult to find anything that involves plate tectonics. But if successful, it could be the key…
