eldavojohn writes "A group of scientists are disembarking right now to study an open gash in the ocean floor where earth's mantle lays exposed without any crust covering it. The scientists describe this as the result of the mantle moving too quickly for the crust to keep up. Either that, or the mantle was never covered by the crust and just has always been like this. From the article, 'Regardless of how they formed, the exposed mantle provides scientists with a rare opportunity to study the Earth's rocky innards. Many attempts to drill deep into the planet barely get past the crust.'"