Titanic director tweets from ocean's deepest point

Titanic director and deep-sea diving enthusiast James Cameron has tweeted from the bottom of the ocean's deepest point, down 36,070 feet in the Marianas Trench's Challenger Deep, and promising unseen footage of the inhospitable region. Cameron's dive is the first single-person attempt ever, with the director squeezing himself into a bullet-shaped submersible capable of withstanding the 15,969 PSI pressures.

"Just arrived at the ocean's deepest pt. Hitting bottom never felt so good" Cameron tweeted from the submarine. "Can't wait to share what I'm seeing w/ you."

The dive takes Cameron – a self-confessed undersea addict – roughly three times as deep as the resting place of the Titanic. There, he will use 3D cameras and other equipment to comprehensively capture as much of the environment as possible; in fact, Cameron's own space inside the submersible is significantly constrained by accommodating the technical hardware he specified.

It's not only space which is an issue: heat from the camera and safety equipment makes the beginning of the dive uncomfortable, while other extremes of temperature become an issue the deeper Cameron goes.

The tweet may be the deepest to-date, but this isn't the first time we've seen social networks used in unusual situations. Astronauts on the International Space Station have tweeted, claiming the mayorship of the orbiting habitat on Foursquare – cheat your way to stealing that, Philip Berne! – as have mountain explorers and other expeditions.