Space is not the final frontier. Humankind has stumbled about the surface of the Moon, hurled satellites beyond the edge of the solar system -- we even have a rover trundling about the surface of Mars several million kilometres away, zapping rocks and poking Martian soil.
But the final frontier is far closer to home. The Earth's mantle, which sits beneath the outer crust we call home, has never been reached by humankind. An international team of scientists from the Integrated Ocean Drilling Program (IODP) is set to embark on a $1 billion (£617 million) expedition to drill into the mantle layer, and make history by collecting the first ever mantle samples.
The Earth's mantle is 3,000km thick, sitting beneath the Earth's crust -- a layer of continental plates some 35-70km in thickness and oceanic basins of five to ten kilometres thickness. The multidisciplinary team from the IODP has selected three possible locations in the Pacific Ocean where the crust has been formed by spreading oceanic ridges and is at its thinnest. When one of these sites is selected, they hope to drill six kilometres down into the mantle.
However, several technical difficulties standing between the IODP team and the mantle layer. They will be working aboard the Japanese deep-sea drilling vessel, Chikyu, capable of carrying some ten kilometres of drilling pipes. Sitting between them and the ultra-hard igneous oceanic basin will be four kilometres of Pacific Ocean. Once the drilling equipment is successfully lowered through the ocean water and secured, they will set about drilling a hole through the oceanic basin only 30cm wide. The drill bits will need to be replaced after every 50 to 60 hours use, adding to the difficulty of the project as new drill heads will need to be guided into the 30cm hole from a ship four kilometres above.
Such is the challenge facing the team, the project co-leader Damon Teagle of the University of Southampton told CNN that the mission was "the most challenging endeavour in the history of Earth science". "It will be the equivalent of dangling a steel string the width of a human hair in the deep end of a swimming pool and inserting it into a thimble one tenth of a millimetre wide on the bottom, and then drilling a few metres into the foundations," said Teagle. "[The mantle] is the engine that drives how our planet works and why we have earthquakes and volcanoes and continents. We have the textbook cartoons but detailed knowledge is lacking." Should the team be successful in the drilling operation, they will be able to retrieve several samples approximately eight centimetres across and nine metres in length, from a never-before reached layer that makes up some 84 per cent of our planet.
The IODP are still short of their funding target of $1 billion (£617 million), with the Japanese government one of the largest current funders. Teagle is hopeful that if further funding is found, they could start drilling before the end of the decade.
This article was originally published by WIRED UK
