A controversial hypothesis, presented by Paul Silver at last December’s AGU Fall Meeting in San Francisco, was featured in a December New Scientist article entitled “The day the Earth stands still.” According to Silver, plate tectonics on Earth will stop in about 350 million years—and such an event may even have been an integral part of Earth’s history.

Earth’s surface is made up of tectonic plates that float on the more viscous mantle below. Their movement relative to each other causes earthquakes and volcanic activity. It also rips continents apart, allowing slivers of water to develop into oceans. Oceans basins can also disappear when one plate slips under another—subduction—bringing land-masses closer together until they eventually form superconinents. According to Silver, about 1.6 to 1.1 billion years ago, as a supercontinent called Rodinia formed, tectonic activity on the planet may have stopped.

For the full article, see the December issue of the New Scientist. The full text is also available online for subscription holders.