• 3 months ago
Lurking under the sea is a global web of fibre optic telecommunication cables – the plumbing of the internet. It's how we talk, text and stream, connecting billions of people. These cables are also the frontline of a tech war.


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Transcript
00:00If a shark bites the Internet cable at the bottom of the sea, how is it repaired?
00:05Above all, how is it known where the cable is broken in thousands of miles of sea?
00:10Starting from this video, the entire traffic on YouTube passes through the hidden cables at the bottom of the sea,
00:17a traffic highway that we use every day but cannot see.
00:21Once again, welcome to World Stories Videos.
00:25The network of undersea cables is so big that it connects all the continents.
00:30These cables are laid at a maximum depth of 8,000 meters where the pressure is 5,300 kilograms per square inch.
00:38This is like putting the weight of an African elephant on the smallest finger of a human foot.
00:43Under such high pressure, the smallest part of the undersea cables is passing under the Black Sea between Azerbaijan and Turkmenistan,
00:51whose length is about 300 kilometers and the largest part is 6,600 kilometers long which is named Maria Cable.
00:59It starts from Virginia Beach in America and passes through the dark depths of the Atlantic Ocean and ends at Bilbao in Spain.
01:07If we talk about the cables laid in all the seas of the world, then the total length of all these is more than 14 million kilometers.
01:14So much that if these cables are wrapped around all the planets of our solar system and their masses,
01:20then still enough cable will be left to go around the Earth once again.
01:24Now obviously laying such long cables, that too at a depth of 8,000 meters in the sea, is not an easy task.
01:31The maximum cost of laying just 1 kilometer of submarine cable is 2.5 million US dollars.
01:39So now you can guess for yourself how much it would have cost to lay 14 million kilometers of cable.
01:44But what was the need to do all this when in today's era, the same work can be done with the help of satellites to keep the whole world connected wirelessly?
01:53Actually, there are 493 submarine cables in the whole world.
01:58Each cable can handle 4,000 terabytes of data, that too in just one second.
02:04Understand it this way that 8 crore people can stream a 4K movie simultaneously on just one cable and there are 493 such cables.
02:13On the contrary, if a satellite does the same work, then only 24,000 people will be able to watch the same 4K movie simultaneously on one satellite.
02:23Now, to fulfill the demands of the people, more and more satellites will have to be installed, which will cost more and require maintenance.
02:32Compared to submarine cables, the maintenance of satellites is more costly and difficult and if due to some reason a major fault occurs in the satellite, then it will have to be repaired.
02:42Replacing it will cost 400 million US dollars.
02:46This is the reason why laying a cable of millions of kilometers under the sea is easier than satellite or wireless connectivity.
02:54Crores of gigabytes of data are traveling all the time on this undersea highway.
02:59This means that this highway will also be quite wide, that is, these cables will be thicker than a common domestic fiber optic cable, but this is not so.
03:09This yellow and black cable looks as thick as a hose pipe, but in reality the fiber optic cable passing through it is as thin as a hair.
03:17So now the question arises how much data is sent through such a thin wire.
03:22This hair-sized wire is called the core of fiber optic, which is made of glass or plastic.
03:28Light passes through it, which travels carrying data in small packets.
03:32First of all, the data present in the computer is converted from electrical signals to light signals with the help of a transmitter.
03:40Transmitter is done.
03:42This work is done through laser light or LED.
03:46This light signal is transmitted in the form of pulses, which have only two parts, ones and zeros.
03:52Light pulse indicates one and when there is no pulse, it indicates zero.
03:57It is the work of the core to take these pulses from one place to another through which light travels.
04:03There is a layer outside this core, which even if it tries to reflect, the layer makes it bounce back inside the core.
04:10This process is called total internal reflection.
04:14Now this light signal becomes weak at a greater distance, for which a repeater is installed after every 100 kilometers, which boosts the light signal.
04:23To complete this part, a DC current of 100,000 volts is sent in the core and gladius because there is no power source in the middle of the ocean.
04:32To power these amplifiers, the current passing through the copper layer is used.
04:37Fiber optic cables are capable of transmitting more than one signal simultaneously.
04:43This technique is called wavelength division multiplexing, DMM.
04:48Light of different colors is passed through fiber optics simultaneously and each color of light contains different data packets.
04:55As you know, the speed of light is 1079 million kilometers, which means that this data travels from one place to another in the blink of an eye at the speed of light.
05:06On reaching thousands of kilometers, this data is converted into electrical signals again with the help of photodiode or photodetector
05:14and then the computer or mobile device reconstructs it and brings it in graphics or any other form.
05:20The cables have to be protected from cladistic pressure, but despite this, these cables are vulnerable to earthquakes, shark attacks and underwater accidents.
05:30Volcanic eruptions can damage many cables, but submarine cables are the most likely to be damaged.
05:36The reason for this is fishing.
05:39Some vessels hunt the fishes living at the bottom of the sea with this trawl door, which has a rope attached to it, which is directly connected to the vessel.
05:47This trawl door is sent to the bottom and is dragged on the ocean floor and then the fishes get trapped in it.
05:53When this trawl door is accidentally thrown at the place of the submarine cable, then the cable gets damaged due to the dragging.
06:01Now here the same question must be coming to your mind.
06:04If submarine cables get damaged at the bottom of such a vast and desolate sea, then how are they repaired?
06:10Repairing is a matter of later, but first of all how is the location of thousands of kilometers of wire damaged and how is that location pinpointed?
06:19Let us tell you here that nowadays modern submarine cables are one inch thick and one kilometer of wire weighs about 1,400 kilograms.
06:28That is, thousands of kilometers of such wire is installed in one piece on the bottom of the sea with the help of special ships for installation in the sea, as much as a sedan car.
06:39After complete research, when a specific area is selected, then big rolls of wire are loaded on the ship and brought to that location and a special robotic machine,
06:49which has the capability to walk on the seafloor, is used to dig the floor up to one meter and cable is laid in it simultaneously.
06:56This is very slow work, which is very important to be done with great caution.
07:01According to an estimate, it took about two years to install the 6,600 kilometers wire to be laid between the US and Europe.
07:10When the wire kept in one vessel gets exhausted, then another vessel filled with cable is put in and the laying work is carried forward by connecting the corner of the first wire with the new wire.
07:21The biggest obstacle in this entire work is the weather of the Atlantic.
07:25There is a series of strong winds in the ocean 365 days a year and no one can stop these winds from turning into a sea storm.
07:34Apart from this, there are often Category 1 hurricanes in the Atlantic Ocean.
07:40Even at this time, when I am doing research for the video, there is a Category 1 hurricane in the Atlantic Ocean, which according to the forecast will reach the coast of Ireland on August 23rd.
07:51Due to hurricanes or strong storms, the installation work is paused for many days until the weather clears.
07:58Now when the installation work itself is so difficult, then imagine how difficult the repair work would be.
08:04There are data centers at both the end points of the submarine cable which monitor the cable's activity 24-7.
08:11As soon as the connection between the two breaks, it means only one thing that the cable has broken in the middle of the ocean thousands of kilometers of wire.
08:20To find out exactly where the damage has occurred, a special device is used which is called Optical Time Domain Reflectometer.
08:28This device sends a light pulse from both ends and because the cable is broken, that light pulse bounces back.
08:35The time taken by the returning pulse to return and the strength of the signal left is used to estimate exactly after how many kilometers the damage has occurred in the cable.
08:45The same process is done from both ends and it is verified whether the location of both is the same or not.
08:52Now the DC supply IE, the current released in the cable, is turned off from both ends and ROVs are sent to the bottom of the sea at that location.
09:01With the help of ROVs, the physical cable is first measured and then the cable is taken out and brought to the vessel present above.
09:09The part of the cable which is damaged is cut and another piece of fiber optic core is inserted in it.
09:15Because it is made of glass, this work has to be done very carefully so that one glass joins the other just like it was in one piece.
09:23This process is called splot.
09:26If the cable is falling short or the bottom of the sea is very low, then first one part is lifted up, another extra wire is added to it and it is laid down again.
09:36Then the same process is done on the other end of the broken wire.
09:40You must have got the answers to many of your questions about the benefits of submarine fiber optic cable, how it works, installation and repair.
09:49Hope you will like and share this video of world stories.
09:53Thank you very much for the loving comments.
09:56See you in the next great video.

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