# Eli5 How does the teeny tiny ‘actual’ undersea internet cable transport all the information requests from both sides of the Atlantic?

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If the huge layers of cables around it are just for protection, how can the large number of requests be transmutted through a cable that thin?

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Data isn’t a physical object which needs a certain diameter of cable to travel through, like an oil pipeline or something, it only depends on the ability to rapidly vary the signal in order to convey information. The more quickly the signal can be varied the more quickly information can be transferred, and those cables have switching equipment on either end which are capable of *very* fast switching.

Another technique is to use the same fiber to transmit information using different frequencies of light. In essence there are multiple conversations taking place just at different “colors” of light, and by applying various filters each of the many different conversations can be separated out from their combined signal.

The thickness doesn’t matter. Per wire only one signal can exist at a given timepoint, no matter how thick it is.

And there you got your solution: you have to send the signals in very short time intervals. In an optical cable those are just extremely short pulses of laserlight.

The limiting factor for that is “dispersion”. That is how much the signal gets “smeared” over time. That is caused by tiny impurities in the glass fibres, wich randomly make parts of the signal slower so a _| pulse gets stretched into a _/ (so if you transmit too fast they blur into each other)

Data doesnt have a volume like water or electricity. To move lots of data around you need high frequencies. These little electrons which transport the data for us are not travelling through the cable – instead they are sitting in a nice long line; if data arrives the electron gives a “lady bump” with its hips to the next electron, this repeats this etc. So the speed of transportation is limited by the frequency of the hip bumps we can feed to these electrons with our equipment, but not by the thickness of the cable.

Fiber optics. The cable is a bundle of tiny tubes the size of a human hair and they use lights or lasers to transmit data. It quite an amazing thing to see. There are videos on YouTube. Check them out. Very educational

From what we know, light has no mass, so “fitting” light into space is not a problem. I believe engineers have created a fiber optic strand that could fit all internet traffic at one time with tons of “room” to spare, it is roughly 8 million times faster than home internet.

The difficulty is engineering the rest. For example, having a laser that can pulse fast enough to transmit the signal, repeaters (devices that keep the light going strong because it will dissipate over time) at the bottom of the ocean, and other issues that might impact the spatial and spectral integrity of the signal, and of course, getting high-speed internet to more places in the world.