The oceans' floors are less well-mapped than the surface of the moon, but thanks to a revolutionary hi-tech diving suit might be make it easier to explore them.
A revolutionary new 'Exosuit', designed to allow divers to spend hours, or even days, underwater has been used to explore the site of a 60BC Roman shipwreck off the island of Antikythera, Greece. The wreck is the location of the discovery of the world's first computer – the 2,000 year-old Antikythera mechanism, a clockwork device it's believed was used to predict eclipses.
Designed by Vancouver company Nuytco Research Ltd, the Exosuit weighs 40 stone (317.5kg) and has a number of innovations to enable divers to remain underwater. These include the ability to recycle ordinary air, which removes the need for compressed oxygen, rotatable joints to aid manoeuvrability and four thrusters which allow the diver to propel themselves through the water.
A team from Woods Hole Oceanographic Institute descended to the wreck, which was explored by Jacques Cousteau in 1976. However, due to "the bends" – bubbles of nitrogen expanding in the blood and joints, as divers return to the surface – Cousteau's team could only spend a few minutes at the wreck, whereas the Woods Hole team could stay down for hours.
"It was like riding a bicycle," said Edward O'Brien, a diver who explored the wreck, "Sitting on a seat inside the suit and operating levers, like inside a little submarine with bendy arms and legs."
Unlike a submarine, the Exosuit's manoeuvrability allows the diver to squeeze into cramped spaces. The pincers on the arms act like hands, allowing them to sift through silt and extract delicate artefacts. Crucially, the diver can remain underwater for up to 50 hours – as long as they do not need the toilet.
"There is no spare room even for a sandwich," says Brendan Foley, another of the divers who explored the Antikythera site, "and there are calls of nature to deal with."
Despite this minor problem, the Exosuit has already captured the imagination of Titanic film director James Cameron, who piloted Deepsea Challenger to the bottom of 6.75 mile deep Mariana Trench in the Pacific in 2012.
Cameron has donated the sub to the Massachusetts team and has said he might use the Exosuit to film the sequel to his blockbuster sci-fi animation Avatar.