Australia is connected to the world by cables no thicker than a garden hose – and at risk from sharks, accidents and sabotage

Last month two Baltic Sea cables were damaged and experts say Australia's cables are not immune from threats. How worried should we be?

• Follow our Australia news live blog for latest updates
• Get our breaking news email, free app or daily news podcast

More than 1m kilometres of cables snake along the world's ocean floor, ferrying data between distant lands. Fibre-optic filaments whisk emails, Netflix and military secrets through deep water, where the cord - about as thick as a garden hose - gathers barnacles and seaweed.

Australia is connected to 15 of them (that we know of), with the main landing stations in Sydney and Perth. They are buried under the beach, then fed out into the open water at depths of up to 8km before re-emerging in landing stations in Singapore, Oman and Hawaii, among others.

Sign up for a weekly email featuring our best reads