ARE WE SURFING ON A WAVE OF MAGMA?

Earth’s tectonic plates are like giant fins in a sea of magma that is in constant motion. This viscous material—which breaks through the surface of the Earth from time to time in a burst of volcanic activity ( photo)— is kept in motion in our planet’s interior by two processes. The convective fl ow associated with plate tectonics is caused by cold plates at the surface sinking back into the mantle, while mantle plumes carry heat upward from the planet’s interior. But what would happen if Earth’s core stopped moving? Scientists believe that Germany, for example, would sink by more than 300 feet, causing the North Sea and the Baltic Sea to overspread large northern areas of the country. Iceland could possibly sink by more than 3,000 feet, leaving nothing visible but a small chain of islands. But some places would rise: New York City by more than 300 feet and the Andes in South America by almost 3,300 feet. But is there any danger of Earth’s internal activity ever coming to rest? In order to find out, geologists at Germany’s University of Potsdam ran a simulation of the Earth’s core over a period of 200 million years and came to an astonishing conclusion: The magma inside Earth takes 150 million years to undergo a complete cycle before starting over— thus making it the longest and oldest geological process on the planet. These currents are part of a continuous operation, and it’s unlikely that a whole continent would ever sink into the sea—with just one possible exception. Australia has been tipping to the north and east for the past 100 million years, and Sydney is, indeed, sinking.