Scientists will set out this week to drill a hole into the Indian Ocean floor to try to get below the Earth's crust for the first time. They want to sample rock from the planet's mantle - its deep interior. In the process, the researchers hope to check their assumptions about the materials from which the crust itself is made. It will probably take several years to drop the full 5 to 5.5km, says co-team leader, Prof Chris MacLeod. Read more