your family whatsapp group runs on a hidden  network of undersea cables why should you  

care because modern life is increasingly  dependent on those slinky subaquatic wires  

and they get attacked by sharks from time to  time how do they work what's the future for them  

join us today as we plunge the depths and  ask how the internet travels across oceans  

according to the authoritative submarine cable  map website there are currently 493 active or  

actively under construction sub-sea internet  cables criss-crossing the globe these range from  

the relatively modest 300 kilometer azerbaijan  to turkmenistan wire running under the black sea  

to the absolutely gargantuan 6600 kilometer  maria cable linking virginia beach in the us  

with bill bow in northern spain maria weighs  the same as 24 blue whales apparently the  

firm's laying down this serpentine superhighway  worldwide there's now 1.5 million kilometers of  

undersea data wires arcadey about how much it  all costs but professional estimates indicate  

a typical transoceanic cable should set you  back between three and four hundred millions of  

dollars which seems like a lot because they're not  especially thick typically around the girth of a  

garden hose and that includes layers of protective  thixotropic jelly around the all-important fiber  

optic core plus multiple plastic sheaths and  copper wiring to power the thing but even so  

on average they can ferry an awesome 100  gigabytes per second in data with newer and  

forthcoming cables able to transmit 400 gigabytes  per second so how does so much data fit down such  

slim channels part of the answer is an extremely  sophisticated data wrangling technique known as  

dense wavelength division multiplexing put simply  dense wavelength division multiplexing lets data  

providers use more than one wavelength of light  to convey information fibre optically instead  

several wavelengths are employed simultaneously  and stacked creating astonishing data speeds this  

happens at buzzing data center-like landing sites  at either end of the cable are the cables just  

straight forward long wires not quite every 70  to 100 kilometers or so along the seabed cables  

are punctuated with so-called repeaters these  essentially serve as amplifiers keeping the signal  

strength up to par over long distances that's  why the cables incorporate copper conductors  

by the way carrying up to 10 000 volts of dc  to power the repeaters how are the cables late  

they're first coiled into vast cylindrical drums  on specialized cable laying ships as much as a  

year's planning and charting will go into plotting  the perfect trans-oceanic route bad locations  

for undersea cables include anywhere volcanic or  anywhere especially earthquake or mudslide prone  

or anywhere heavily trolled by fishermen the  cable is spooled out the back of the ship at a  

sedate pace of around 10 kilometers an hour if the  ship encounters bad weather the captain can decide  

whether to break off the cord tie it to a boy and  retreat to karma waters when the storm passes the  

ship returns to the boy and picks up where it left  off accidents and outages on the cables can and do  

occur in 2012 hurricane sandy in the u.s knocked  out several key transatlantic cables disrupting  

networks for hours in 2011 the fukushima  earthquake in japan caused similar online  

the vast majority of such disruptions however  are the result of human carelessness typically  

trawler nets or wayward ships anchors cables  situated close to the shore are significantly  

more at risk from such disruption as such the  nearer to lander cable is the more likely it'll  

be carefully armor-plated many are even dug  into the seabed in long dedicated trenches  

carved out using ship-drawn plows awesomely sharks  have been spotted nibbling on one of google's  

subsea cables get your teeth into this 2014 clip  more sinister even than that the us government  

has consistently warned of interference in the  cables from hostile foreign powers like russia  

or china the us government should know all about  that whistleblower edward snowden revealed in 2013  

how the nsa had no qualms eavesdropping on fiber  optic communications the geopolitical implications  

of undersea cables are also fascinating last year  the australian government intervened to prevent  

chinese technology giant huawei from installing  a cable connecting australia with the solomon  

islands the fear is that china could use the link  to gain access to australia's sensitive internal  

networks so who actually owns these cables that's  an interesting question it's an expensive business  

so historically nations or quasi national telecom  providers have picked up the bill the world's  

biggest owner of cables remains america's a t with  a stake in some 230 000 kilometers of undersea  

cable the second biggest owner is china telecom  frequently cables are owned by groups or consortia  

of up to 50 separate owners including tech firms  local government agencies and other businesses  

and while this model helps spread the initial  cost it's less helpful when something goes wrong  

and nobody can agree who has to put on a wetsuit  and do something about it increasingly big tech  

is recognizing its scope for growth is limited  by the undersea cable network so over the past  

few years the overwhelming majority of investment  in undersea cable infrastructure has come from  

companies like facebook which currently owns  nearly 100 000 kilometers of cables google owns  

roughly the same amount amazon has its own massive  private network hooking up the online giant's  

mighty aws data centers through cables traversing  the atlantic pacific and indian oceans plus the  

mediterranean and the red sea and the south  china sea the tech giants like to frame these  

vast environmentally disruptive infrastructure  projects a civilization enhancing largesse on  

their part but they're also shareholder companies  remember who know perfectly well that increasing  

the number of human beings online is the only way  they can continue to grow hang on a second you're  

probably thinking what about starlink isn't  our old mate elon about to make the internet  

wireless any day now for now cable is by  far the cheapest and most efficient means  

of eating vast packets of data over incredibly  long distances fast even normally bullish musk  

says starlink is only aimed at people who don't  presently enjoy access to high speed fiber but  

who knows how that'll pan out in a decade or two  for now the future is very much undersea cables  

only this summer google and facebook announced  a joint initiative to build an undersea cable  

named apricot apricot will link up singapore  japan guam the philippines taiwan and indonesia  

by the year 2024. the longest subaquatic cable  ever a 45 000 kilometer billion dollar monster  

called to africa that will link up 33 nations was  just bankrolled by a facebook-led consortium what  

do you think will mankind's ingenious submarine  network one day look as obsolete as the telegraph  

let us know in the comments and don't forget to  subscribe for more totally wired tech content