The internet is the wider network that allows computer networks around the world run by companies, governments, universities and other organisations to talk to one another. The result is a mass of cables, computers, data centres, routers, servers, repeaters, satellites and wifi towers that allows digital information to travel around the world.
It is that infrastructure that lets you order the weekly shop, share your life on Facebook, stream Outcast on Netflix, email your aunt in Wollongong and search the web for the world’s tiniest cat.
How big is the internet?
One measure is the amount of information that courses through it: about five exabytes a day. That’s equivalent to 40,000 two-hour standard definition movies per second.
It takes some wiring up. Hundreds of thousands of miles of cables criss-cross countries, and more are laid along sea floors to connect islands and continents. About 300 submarine cables, the deep-sea variant only as thick as a garden hose, underpin the modern internet. Most are bundles of hair-thin fibre optics that carry data at the speed of light.
The cables range from the 80-mile Dublin to Anglesey connection to the 12,000-mile Asia-America Gateway, which links California to Singapore, Hong Kong and other places in Asia. Major cables serve a staggering number of people. In 2008, damage to two marine cables near the Egyptian port of Alexandria affected tens of millions of internet users in Africa, India, Pakistan and the Middle East.
Last year, the chief of the British defence staff, Sir Stuart Peach, warned that Russia could pose a threat to international commerce and the internet if it chose to destroy marine cable.