A Big Whack That Made the Moon May Have Also Created Continents That Move
by Lucas Joel
Some 4.5 billion years ago, many scientists say, Earth had a meetup with Theia, another planetary object the size of Mars. When the two worlds collided in a big whack, the thinking goes, debris shot into space, got locked into the orbit of the young, damaged Earth and led to the formation of our moon.
But the collision with Theia may have done more than that, according to a study published last month in the journal Geophysical Research Letters. The impact may have given rise to something else: plate tectonics, the engine that drives the motion of Earth’s giant continental and oceanic plates and causes earthquakes, volcanic eruptions and the eventual remaking of our planet’s surface about every 200 million years.