Resumen de Earth's billion-year youthful rampage
Marshall talks about the planet Earth. Earth has calmed down in its middle age. Earth was at its most active 1.1 billion years ago, when all the continents collided into one huge supercontinent, and has been getting calmer ever since. It's evidence that the planet has a kind of lifespan. Earth's surface layer, the crust, is divided into tectonic plates that constantly jostle against each other. When two plates collide, they can be forced up into mountains, or one plate can slide under another and be destroyed.
