New technology will connect large swathes of land and most of the ocean depths to the internet

The internet may feel like it's everywhere, but large pockets of sky, swathes of land and most of the ocean depths are still beyond a signal's reach.

Three decades after the first cellphone went on sale - the US$4,000 Motorola DynaTAC 8000X "Brick" - half the world remains unconnected. For some it costs too much, but up to one-fifth of the population, or some 1.4 billion people, live where "the basic network infrastructure has yet to be built", according to a Facebook white paper released last month.

Even these figures, says Kurtis Heimerl, whose Berkeley-based start-up Endaga has helped build one of the world's smallest telecom networks in an eastern Indonesian village, ignore the many people who have a cellphone but have to travel hours to make a call or send a message. "Everyone in our community has a phone and a SIM card," he says. "But they're not covered."

Heimerl reckons up to two billion people live most of their lives without easy access to cellular coverage. "It's not getting better at the dramatic rate you think," he said. The challenge is to find a way to connect those people, at an attractive cost.

And then there's the frontier beyond that: the oceans.

Improving the range and speed of communications beneath the seas that cover more than two-thirds of the planet is a must for environmental monitoring - climate recording, pollution control, predicting natural disasters like tsunami, monitoring oil and gas fields and protecting harbours.

There is also interest from oceanographers looking to map the sea bed, marine biologists, deep-sea archaeologists and those hunting for natural resources, or even searching for lost vessels or aircraft. Canadian miner Nautilus Minerals said last week that qit came to an agreement with Papua New Guinea, allowing it to start work on the world's first undersea metal mining project 1,500 metres beneath the Bismarck Sea.