WEBVTT - The History of Subsea Cables 0:00:04.400 --> 0:00:07.800 Welcome to tech Stuff, a production from I Heart Radio. 0:00:12.119 --> 0:00:14.680 Hey there, and welcome to tech Stuff. I'm your host, 0:00:14.840 --> 0:00:17.560 Jonathan Strickland. I'm an executive producer with iHeart Radio and 0:00:17.600 --> 0:00:22.160 I love all things tech and longtime listener and Tricks 0:00:22.320 --> 0:00:24.840 wrote in on Twitter to ask if I had done 0:00:24.880 --> 0:00:30.520 an episode on undersea cables, and you know what, I haven't. 0:00:31.320 --> 0:00:34.800 So today we're going to start to talk about them, because, 0:00:34.840 --> 0:00:37.120 as it turns out, there's a lot to cover with 0:00:37.280 --> 0:00:42.120 undersea cables to kind of understand not just how they work, 0:00:42.400 --> 0:00:46.280 but the challenges that people faced in order to make 0:00:46.360 --> 0:00:49.200 them a reality in the first place. This is also 0:00:49.240 --> 0:00:53.280 a timely topic because recently a company called x Links 0:00:53.720 --> 0:00:58.360 made headlines for the Morocco UK power plant project. That 0:00:58.400 --> 0:01:01.080 project's goal is to create a bowler and wind farm 0:01:01.160 --> 0:01:05.039 in Morocco and use a very very long sub sea 0:01:05.319 --> 0:01:09.760 power chord, essentially to send electricity to the UK. Now, 0:01:09.959 --> 0:01:12.840 while a lot of headlines called this the longest subseed cable, 0:01:13.240 --> 0:01:16.880 that's misleading because there are actually many different types of cables, 0:01:17.400 --> 0:01:22.399 and technically the ce ME WE three cable that's s 0:01:22.440 --> 0:01:26.200 E A dash M E dash W E three, the 0:01:26.280 --> 0:01:30.080 number three cable is actually about ten times longer than 0:01:30.120 --> 0:01:33.679 what the Morocco UK cable will be. But we're gonna 0:01:33.720 --> 0:01:36.920 get to all that probably in the next episode, definitely 0:01:37.000 --> 0:01:40.200 not this one. But as and Tricks pointed out in 0:01:40.240 --> 0:01:42.880 a tweet to me, undersea cables trace their history back 0:01:42.920 --> 0:01:47.000 to the mid nineteenth century. So in order to understand 0:01:47.040 --> 0:01:49.279 all of this, we really have to take a moment 0:01:49.320 --> 0:01:52.360 and talk about the telegraph and the development of the 0:01:52.440 --> 0:01:55.800 first undersea cables. So there were a few things that 0:01:55.880 --> 0:01:59.800 had to happen for undersea cables to even become a necessity. 0:02:00.320 --> 0:02:02.480 You know. One of those was the development of the 0:02:02.480 --> 0:02:06.520 electric telegraph, because without that, there's no need to worry 0:02:06.560 --> 0:02:09.440 about subsea cables. Right, If you don't have long distance 0:02:09.520 --> 0:02:13.200 electric based communication, then cables aren't really a thing you 0:02:13.280 --> 0:02:16.839 gotta worry about, at least as far as connecting, say 0:02:16.919 --> 0:02:21.880 an island to a continent. Now, the word telegraph is 0:02:21.960 --> 0:02:27.240 Greek and it means essentially distant writing. But this word 0:02:27.280 --> 0:02:33.079 actually predates electric telegraphs. For example, there were semaphore systems, 0:02:33.320 --> 0:02:37.040 ones that used visual cues with flags. Those were used 0:02:37.120 --> 0:02:40.440 throughout France, and we're really developed during the Napoleonic wars, 0:02:41.120 --> 0:02:45.040 and that was referred to as telegraph. Before any kind 0:02:45.040 --> 0:02:48.200 of electric version came along in the late seventeen hundreds, 0:02:48.560 --> 0:02:52.440 you had various smarty pants around the world experimenting with electricity, 0:02:53.080 --> 0:02:56.280 you know, like Ben Franklin, and this was just something 0:02:56.320 --> 0:02:58.760 that was just beginning to be understood at the time. 0:02:59.240 --> 0:03:03.400 Alissandre of Volta had created a sort of proto battery 0:03:03.440 --> 0:03:06.399 that we later called a voltaic pile or and then 0:03:06.560 --> 0:03:10.240 later on we had the voltaic cells. These inventions could 0:03:10.240 --> 0:03:14.160 produce a good electric current, but at a very low voltage. 0:03:14.280 --> 0:03:16.880 Now we need a reminder here because we're gonna be 0:03:16.880 --> 0:03:21.520 talking about electricity a lot. Voltage in electricity is sort 0:03:21.520 --> 0:03:24.799 of similar to water pressure in a plumbing system. You 0:03:24.840 --> 0:03:28.240 can think of it as how much oomph a current has, 0:03:28.840 --> 0:03:32.160 and current you can think of as the amount of 0:03:32.240 --> 0:03:39.360 electricity present in a system of flowing electricity or flowing electrons. So, 0:03:40.160 --> 0:03:42.760 if we want a really quick analogy, if you had 0:03:42.800 --> 0:03:47.040 a low voltage, high current source of electricity, that's kind 0:03:47.040 --> 0:03:50.040 of like a lazy river, right. The river can be 0:03:50.120 --> 0:03:52.640 really wide and it might be really deep, so you've 0:03:52.640 --> 0:03:55.160 got a lot of water there, but that water isn't 0:03:55.240 --> 0:04:00.480 moving very quickly. It's just lazily going down. A high voltage, 0:04:00.680 --> 0:04:06.360 low current electric device produces a very tight, high pressured stream. 0:04:06.480 --> 0:04:10.400 So think of like a a concentrated stream of water 0:04:10.480 --> 0:04:13.880 coming out of a pressure hose. You don't it's not 0:04:14.000 --> 0:04:16.839 nearly the same amount of water as the lazy river. 0:04:17.080 --> 0:04:20.800 It's much less current in other words, but the pressure 0:04:21.320 --> 0:04:27.520 or voltage is way higher. Well before Volta's discovery, scientists 0:04:27.520 --> 0:04:30.840 and engineers were mostly reliant on devices that would build 0:04:30.920 --> 0:04:35.039 up electrostatic charges. So electro static charges have a high 0:04:35.120 --> 0:04:39.080 voltage but a low current, and they have limited applicability 0:04:39.640 --> 0:04:43.320 in things where you need sustained electric current. So Volta's 0:04:43.480 --> 0:04:48.440 invention would allow for new applications of electricity. Now in 0:04:48.480 --> 0:04:51.800 the early eighteen hundreds you had some other smarty pants 0:04:51.839 --> 0:04:56.120 like Hans Christian Orstead of Denmark. And by the way, 0:04:56.600 --> 0:05:00.360 as always, my apologies for all the mispronunciation, and I'm 0:05:00.360 --> 0:05:03.080 going to do of all the different names that is 0:05:03.120 --> 0:05:07.720 on me and I apologize. However, he discovered that electricity 0:05:07.760 --> 0:05:11.880 and magnetism have a connection. He observed that a magnetic 0:05:11.960 --> 0:05:17.279 needle would deflect from magnetic north if it came close 0:05:17.320 --> 0:05:20.400 to a wire that was carrying an electric current or 0:05:20.480 --> 0:05:24.039 transmitting an electric current, and so we first began to 0:05:24.080 --> 0:05:27.680 realize that electro magnetism is a thing, that there is 0:05:27.760 --> 0:05:33.200 this relationship between electricity and magnetism. This would lead to 0:05:33.480 --> 0:05:36.080 yet more smarty pants people thinking of ways that we 0:05:36.120 --> 0:05:41.320 could use electricity through wires to communicate across vast distances. 0:05:42.000 --> 0:05:45.359 One way, a way that Sir William Father gil Cook 0:05:45.600 --> 0:05:50.280 and Sir Charles Wheatston suggested was to have a multi 0:05:50.320 --> 0:05:55.240 wire system that would use up to five needles. They 0:05:55.279 --> 0:05:59.000 experiment with different ones, but the one that they would 0:05:59.080 --> 0:06:03.279 use heavily would have five needle pointers, and that would 0:06:03.320 --> 0:06:06.120 be at the receiving end of this system. So you 0:06:06.120 --> 0:06:09.880 could send different electrical signals down these different wires and 0:06:09.920 --> 0:06:13.960 thus direct these needles these pointers to point to different 0:06:14.120 --> 0:06:18.680 letters on a placard that would have the alphabet there. 0:06:19.160 --> 0:06:21.240 Uh The system would remain in use in the UK 0:06:21.480 --> 0:06:24.760 up through the early twentieth century, so the UK was 0:06:24.800 --> 0:06:27.479 reliant on this system, whereas the rest of the world 0:06:27.520 --> 0:06:30.400 would move on to other ones. The neat thing about 0:06:30.400 --> 0:06:33.240 the system is that it arranged the alphabet in a 0:06:33.360 --> 0:06:37.960 diamond pattern, so it only used twenty letters of the alphabet. 0:06:38.000 --> 0:06:42.400 It left out the letters C, J, Q, U, X, 0:06:42.440 --> 0:06:44.800 and z, so sometimes you had to do, you know, 0:06:46.040 --> 0:06:50.040 approximations of certain words. And the letter A was at 0:06:50.080 --> 0:06:52.600 the top point of the diamond, and then you know, 0:06:52.640 --> 0:06:54.840 you had B and D at the next level, and 0:06:54.880 --> 0:06:56.479 then so on and so forth, and then at the 0:06:56.520 --> 0:07:00.360 bottom you had the letter Y. And the five needles 0:07:00.360 --> 0:07:03.000 were split right in the middle of this diamond. They 0:07:03.000 --> 0:07:05.760 were in the widest part of the diamond, pointing up 0:07:05.800 --> 0:07:07.880 and down normally, which meant that they weren't pointing at 0:07:07.880 --> 0:07:12.560 any specific letter. So by sending signals down specific wires, 0:07:13.000 --> 0:07:16.000 you could make needles point to a specific letter. You 0:07:16.040 --> 0:07:18.360 would have both of you know, two needles that were 0:07:18.360 --> 0:07:22.640 on a diagonal line with a specific letter, and by 0:07:22.760 --> 0:07:26.040 looking at the common letter that both needles were pointing at, 0:07:26.360 --> 0:07:30.120 you could spell out words. An interesting approach, not necessarily 0:07:30.160 --> 0:07:33.640 the fastest, but it worked. Later on, Wheatstone would create 0:07:33.680 --> 0:07:37.560 a different system that had a circular dial uh than 0:07:37.640 --> 0:07:40.480 a needle on the inside, and you had the alphabet 0:07:40.560 --> 0:07:43.720 laid out along the inside circumference of the circle, so 0:07:43.840 --> 0:07:47.000 sort of like an analog clock, except instead of numbers 0:07:47.080 --> 0:07:49.960 for the time, you had the alphabet, and you also 0:07:50.000 --> 0:07:53.360 could have numbers as well. Then you had keys that 0:07:53.400 --> 0:07:56.360 matched the letters and numbers that were along the outside 0:07:56.400 --> 0:07:59.120 of the style. So pressing down on a key would indicate, Okay, 0:07:59.200 --> 0:08:02.560 I want to send this letter UM, and this is 0:08:02.600 --> 0:08:04.840 the sending station, And then you would have a receiving 0:08:04.840 --> 0:08:06.920 station on the other end that would have a similar 0:08:06.960 --> 0:08:09.720 dial with a needle and the letters and numbers in it, 0:08:10.200 --> 0:08:13.280 and pressing down a specific key would end up sending 0:08:13.280 --> 0:08:15.520 a signal that would have the needle on the other 0:08:15.560 --> 0:08:19.640 side point to the relevant letter or number. This way 0:08:20.120 --> 0:08:22.720 was really neat and the way it worked is super cool. 0:08:23.120 --> 0:08:25.200 But I'm gonna have to save that for another episode 0:08:25.200 --> 0:08:28.880 because I'm supposed to focus on subsei cables, and I 0:08:28.920 --> 0:08:31.280 wrote about a page and a half of stuff before 0:08:31.320 --> 0:08:33.960 I realized I am getting way off track, so I'll 0:08:33.960 --> 0:08:36.240 spare you for now, but that will come up maybe 0:08:36.280 --> 0:08:39.880 in a future episode. Now, in America, it was Samuel Morse, 0:08:39.920 --> 0:08:43.640 who interestingly was an art professor who came up with 0:08:43.679 --> 0:08:47.840 the famous method for transmitting messages electrically using a special code, 0:08:48.480 --> 0:08:51.080 one that today, of course, we refer to as the 0:08:51.160 --> 0:08:55.640 Samuel Code. Don't wait no, I'm sorry. No. Morse code. 0:08:55.880 --> 0:09:00.319 Morse code. Morse code uses dots and dashes to rep 0:09:00.440 --> 0:09:04.000 letters and numbers, and by tapping the dots and dashes 0:09:04.080 --> 0:09:07.120 on a telegraph key, you could send pulses of electrical 0:09:07.200 --> 0:09:09.760 signal down a wire, and a receiver at the other 0:09:09.840 --> 0:09:13.120 end could then emboss dots and dashes on a strip 0:09:13.160 --> 0:09:15.439 of paper, so you could actually read out the dots 0:09:15.440 --> 0:09:18.480 and dashes and translate it that way, or later on 0:09:18.920 --> 0:09:23.079 you had engineers who are trained to listen for dots 0:09:23.080 --> 0:09:25.840 and dashes, and you had a device that was essentially 0:09:25.840 --> 0:09:30.400 tapping like a little anvil, tapping out the messages, and 0:09:30.400 --> 0:09:33.720 you would just listen. Later, a guy named Alfred Vale 0:09:33.720 --> 0:09:36.360 would partner with Morse to refine this system and make 0:09:36.400 --> 0:09:39.880 it a little more practical, essentially looking at the most 0:09:40.200 --> 0:09:45.360 frequently used letters and using the the simplest dots and 0:09:45.440 --> 0:09:48.720 dash patterns to represent those letters, as well as to 0:09:48.840 --> 0:09:53.400 redesign the telegraph key itself. By eighteen thirty seven, Veil 0:09:53.480 --> 0:09:56.720 and Morse were demonstrating this technology, and by eighteen forty 0:09:56.800 --> 0:10:00.640 three they secured funding to set up an experiment telegraph 0:10:00.679 --> 0:10:04.040 line that stretched the thirty five miles around sixty kilometers 0:10:04.440 --> 0:10:08.280 between Baltimore, Maryland and Washington, d c Here in America. 0:10:08.920 --> 0:10:13.240 The project used poles that were erected alongside a railroad 0:10:13.320 --> 0:10:17.320 line and wires connected to the poles via glass insulators, 0:10:17.400 --> 0:10:21.600 and it worked. One thing that really amazed me as 0:10:21.600 --> 0:10:24.400 I was doing research into this, just as a quick digression, 0:10:25.000 --> 0:10:29.600 is how quickly things moved. Because this was eight three, 0:10:30.080 --> 0:10:33.400 and we're gonna be talking about a transatlantic subsea cable 0:10:33.440 --> 0:10:37.000 by the end of this episode. That came a little 0:10:37.040 --> 0:10:40.200 more than a decade after that. And to think of 0:10:40.240 --> 0:10:42.680 it being ten years, a little more than ten years 0:10:42.720 --> 0:10:47.000 between stringing sixty kilometers of cable between two cities in 0:10:47.040 --> 0:10:51.760 America to laying a subsea cable across the Atlantic Ocean 0:10:52.480 --> 0:10:56.800 blows my mind. Well, anyway, the demonstration was a success, 0:10:56.880 --> 0:10:59.199 and it didn't take long for railroad companies to start 0:10:59.280 --> 0:11:02.240 building out tell alegraph systems, and early on they were 0:11:02.280 --> 0:11:05.440 almost exclusively used to help keep track of traffic on 0:11:05.480 --> 0:11:07.880 the rail system, to better plan out routes, and to 0:11:07.960 --> 0:11:11.080 avoid long delays or accidents. By the end of the 0:11:11.080 --> 0:11:13.960 eighteen forties, journalists were starting to make use of the 0:11:13.960 --> 0:11:18.720 telegraph system to wire stories across vast distances, and businesses 0:11:18.760 --> 0:11:21.520 began to get interested in this as well, the ability 0:11:21.600 --> 0:11:24.920 to be able to conduct business between cities without having 0:11:25.000 --> 0:11:29.120 to take you know, a train ride or otherwise have 0:11:29.400 --> 0:11:33.120 you know, like like people on horseback travel from one 0:11:33.160 --> 0:11:35.760 city to another. Because keep in mind this is this 0:11:35.840 --> 0:11:39.959 is before the automobile has really become a thing. So yeah, 0:11:40.000 --> 0:11:43.000 there were limited ways of getting information from one point 0:11:43.000 --> 0:11:47.720 to another. However, until eighteen fifty, these distances were all 0:11:47.720 --> 0:11:52.520 over land. The reach of telegraph systems ended at the coastlines, 0:11:53.080 --> 0:11:56.760 which meant that while regions could develop a sophisticated internal 0:11:56.800 --> 0:12:01.319 communications system you know, inside their border or maybe between 0:12:01.440 --> 0:12:05.840 borders of neighboring nations that shared you know, a land border, 0:12:05.960 --> 0:12:08.720 once you hit the ocean, you had to rely on 0:12:08.840 --> 0:12:13.800 other methods, much slower methods. So a mail ship isn't 0:12:13.840 --> 0:12:17.839 a ship that carries mail, not a not a gendered ship, 0:12:18.280 --> 0:12:21.480 but a mail ship between London and New York could 0:12:21.480 --> 0:12:24.560 take nearly a month to travel across the ocean. A 0:12:24.640 --> 0:12:26.520 fast one might be able to make the journey in 0:12:26.679 --> 0:12:31.199 three weeks. By the mid nineteenth century, steamships were largely 0:12:31.240 --> 0:12:33.439 taking the place of sailing vessels. They could make the 0:12:33.520 --> 0:12:36.920 journey in up around ten days, so still more than 0:12:36.960 --> 0:12:40.079 a week to get from one point to another. That's 0:12:40.280 --> 0:12:44.400 pretty slow for news to travel. It was difficult to 0:12:44.480 --> 0:12:48.959 act with alacrity if you were relying upon information from 0:12:49.000 --> 0:12:53.120 across the pond. So there was a strong use case 0:12:53.520 --> 0:12:57.800 to make for creating an undersea cable infrastructure that could 0:12:57.840 --> 0:13:00.680 connect distant parts of the world, you know, parts that 0:13:00.720 --> 0:13:04.600 were separated by oceans, and even in Europe, like England 0:13:04.880 --> 0:13:08.439 in particular, saw the need to do this because while 0:13:08.960 --> 0:13:11.800 the distance was not nearly as great to travel from 0:13:11.880 --> 0:13:17.439 say Dover to France, the delay in getting information from 0:13:17.440 --> 0:13:19.959 other parts of Europe was still pretty considerable, so there 0:13:20.040 --> 0:13:23.480 was definitely a need for that as well. This did, however, 0:13:23.559 --> 0:13:27.080 present some engineering challenges because you had to find a 0:13:27.120 --> 0:13:31.720 way to make this both practical and affordable. Now this 0:13:31.800 --> 0:13:34.199 is going to be obvious, but I need to establish it. 0:13:34.200 --> 0:13:38.040 It is way easier to repair and maintain infrastructure that's 0:13:38.040 --> 0:13:41.400 above the water than it is to do below the water. 0:13:41.840 --> 0:13:46.400 And that's because we live above the water and we 0:13:46.480 --> 0:13:48.880 can't live below the water, at least not with the 0:13:48.920 --> 0:13:52.079 same amount of freedom. And since the Mr folks seemed 0:13:52.160 --> 0:13:56.200 completely uninterested in helping us maintain communication channels. We have 0:13:56.280 --> 0:13:59.440 to take that into consideration. To that end, we have 0:13:59.480 --> 0:14:04.600 to treat cables subseed cables different from terrestrial cables. We 0:14:04.640 --> 0:14:07.679 have to take into consideration what being submersed in ocean 0:14:07.720 --> 0:14:10.480 water is going to do to a cable over time. 0:14:10.760 --> 0:14:14.800 We have to understand that those effects can be detrimental. 0:14:14.840 --> 0:14:16.800 We have to be able to estimate how long a 0:14:16.840 --> 0:14:21.400 particular cable is likely to remain viable, assuming no catastrophic 0:14:21.440 --> 0:14:25.640 instances occur, like assuming that a ship's anchor doesn't tear 0:14:25.680 --> 0:14:28.000 through the cable, for example. So we have to make 0:14:28.040 --> 0:14:31.040 sure that we have the budget to not just install 0:14:31.080 --> 0:14:34.920 a cable in the first place, but to potentially replace 0:14:35.040 --> 0:14:39.040 that cable when we near the end of its estimated lifespan. 0:14:39.560 --> 0:14:42.800 It has to make financial sense, or else it's a 0:14:42.840 --> 0:14:46.400 loss in the long run. Right. So you can argue, yes, 0:14:46.480 --> 0:14:52.320 it's invaluable to have two distant places connected together, but 0:14:52.400 --> 0:14:57.080 if you're constantly having to replace the communication channel, then 0:14:57.360 --> 0:15:01.040 that invaluable might start to take on of value where 0:15:01.040 --> 0:15:03.760 you just say, yeah, it's invaluable, but I don't want 0:15:03.760 --> 0:15:06.240 to pay for it. So coming up with a way 0:15:06.280 --> 0:15:10.080 to make subsea cables work extends beyond just the technology. 0:15:10.920 --> 0:15:13.400 I mean, obviously the tech is a critical component or 0:15:13.400 --> 0:15:18.360 else nothing happens. But you can't ignore the financial element, 0:15:18.560 --> 0:15:22.360 right or the physical challenges, because if you do that, 0:15:22.440 --> 0:15:26.360 you're setting yourself out to fail. So we're gonna take 0:15:26.400 --> 0:15:28.160 a quick break. But when we come back, we're gonna 0:15:28.200 --> 0:15:31.760 talk about a couple of other things before we get 0:15:31.800 --> 0:15:36.200 to the first subseed cable, like some basic things about 0:15:36.520 --> 0:15:40.360 electrical transmission. But before we do that, let's take this 0:15:40.440 --> 0:15:51.360 quick break. All right, So in the eighteen twenties and 0:15:51.440 --> 0:15:55.000 eighteen thirties you had all these various smarty pants is 0:15:55.400 --> 0:15:58.680 is all learning about electro magnetism. And we now know 0:15:59.040 --> 0:16:02.440 that if you pass an electric current through a conductive material, 0:16:03.160 --> 0:16:06.960 that generates a magnetic field. And similarly, should you have 0:16:07.120 --> 0:16:10.800 a conductive material like a wire, encounter a magnetic field, 0:16:11.240 --> 0:16:14.720 that field will induce an electric current to flow through 0:16:15.040 --> 0:16:19.080 the conductive wire. And you've probably played with this in school, 0:16:19.200 --> 0:16:21.920 making a simple electro magnet with like an iron nail, 0:16:22.120 --> 0:16:24.920 some copper wire, and a battery. You know, you connect 0:16:25.000 --> 0:16:28.840 the wire to either terminal of the battery, you've coiled 0:16:28.840 --> 0:16:32.760 the wire around the nail to act as a core, 0:16:33.200 --> 0:16:35.320 and it becomes magnetic. You can pick up paper clips 0:16:35.320 --> 0:16:37.640 and stuff. I remember I did that in school. I 0:16:37.640 --> 0:16:41.520 imagined that people still do well. There's a whole lot 0:16:41.520 --> 0:16:44.320 more to electro magnets, but we're just going to focus 0:16:44.360 --> 0:16:48.080 on a couple of little things first. And the first 0:16:48.120 --> 0:16:52.640 important bit is, because of this relationship between electricity and magnetism, 0:16:52.720 --> 0:16:55.160 we need to make sure that wires and cables that 0:16:55.200 --> 0:16:59.400 we use to transmit electricity have really good insulation around them. 0:16:59.440 --> 0:17:02.880 And that's because us Without insulation, that is, without some 0:17:02.960 --> 0:17:06.959 sort of barrier that resists the flow of electricity and 0:17:07.000 --> 0:17:11.200 the interaction of magnetic fields, you have the potential for interference. 0:17:11.560 --> 0:17:14.920 So let's say you've got two copper cables and there's 0:17:14.920 --> 0:17:18.480 no shielding on them, you don't have any insulation on them, 0:17:18.560 --> 0:17:20.719 and you've got them close to each other. And then 0:17:20.800 --> 0:17:24.760 let's say you send electricity through one of those two cables, 0:17:24.760 --> 0:17:28.440 not the second one, just cable number one. Well, as 0:17:28.440 --> 0:17:32.000 the electricity flows through cable number one, that creates a 0:17:32.040 --> 0:17:35.600 magnetic field which overlaps to the second cable, and that 0:17:35.640 --> 0:17:38.680 induces a current to flow Now, if we're using direct 0:17:38.760 --> 0:17:42.880 current something like a battery, uh, the second cable will 0:17:42.920 --> 0:17:46.480 only have electric current running at the very beginning when 0:17:46.520 --> 0:17:50.320 that magnetic field first hits it, but then it will stop. However, 0:17:50.640 --> 0:17:54.439 if the source is alternating current then which means that 0:17:54.480 --> 0:17:58.000 the current is changing direction many times per second, then 0:17:58.080 --> 0:18:00.520 what you have is a fluctuating magnet at it field. 0:18:00.520 --> 0:18:04.359 Because the magnetic fields direction also changes many times per second, 0:18:04.880 --> 0:18:07.800 that will continue to induce electricity to flow in the 0:18:08.000 --> 0:18:12.480 second cable. This would be in interference. It creates phantom 0:18:12.560 --> 0:18:16.800 signals when no signal is intended, or it interferes as 0:18:16.800 --> 0:18:22.960 one signal overpowers or changes another. I remember back in 0:18:23.000 --> 0:18:26.119 the day, I had these cheap desktop speakers that I 0:18:26.160 --> 0:18:28.520 had connected to my computer, and I would put my 0:18:28.560 --> 0:18:32.160 cell phone down on the desk, and every time my 0:18:32.320 --> 0:18:37.160 cell phone got a notification, it would make this weird 0:18:37.240 --> 0:18:42.199 electric chirping noise in the speakers because that was radio 0:18:42.240 --> 0:18:47.200 frequency interference that was inducing a current to flow through 0:18:47.240 --> 0:18:50.600 the speakers. So these are things that can happen, and 0:18:50.640 --> 0:18:53.040 you don't want them to write. You want to shield 0:18:53.840 --> 0:18:57.520 your components so that only the signals you want to 0:18:57.600 --> 0:18:59.920 send are going through so you have to protect a 0:19:00.000 --> 0:19:03.600 against that. Now, in the nineteenth century, there were people 0:19:03.640 --> 0:19:08.080 who discovered a plant that had a kind of sap 0:19:08.160 --> 0:19:10.719 essentially that was found to be a really effective insulator, 0:19:11.160 --> 0:19:14.280 so it resisted the flow electricity and protects or insulates 0:19:14.280 --> 0:19:18.600 against interference. That material is called Gutta percha. It's a 0:19:18.720 --> 0:19:22.959 biologically derived latex. And like I said, the plant has 0:19:23.000 --> 0:19:25.600 the name Gutta percha, but that's also the name everyone 0:19:25.720 --> 0:19:31.240 used for the derived latex from it. Now, this was 0:19:31.359 --> 0:19:34.439 fortunate at the time, but I should also add that 0:19:34.480 --> 0:19:38.280 the telecommunications industry would spell doom for the Gutta purchase 0:19:38.320 --> 0:19:41.520 trees because the rampant harvesting of the trees created an 0:19:41.600 --> 0:19:47.639 unsustainable situation. And before too long people realize, oh, we 0:19:47.680 --> 0:19:50.679 need an alternative to this, because pretty soon there's not 0:19:50.720 --> 0:19:52.679 going to be any of this plant left on the 0:19:52.720 --> 0:19:56.920 planet will have harvested at all. Anyway, Gutta percha has 0:19:57.160 --> 0:20:00.960 many of the same properties as synthetic rubber, including the 0:20:00.960 --> 0:20:04.920 ability to insulate conductive materials. Next, we need to think 0:20:04.960 --> 0:20:08.000 about what happens with electricity as it travels over greater 0:20:08.119 --> 0:20:11.920 distances of wire um. This is going to get more 0:20:11.960 --> 0:20:15.080 complicated later in this episode, because, as it turns out, 0:20:15.880 --> 0:20:17.520 there are certain things that we have to take into 0:20:17.560 --> 0:20:20.479 consideration with any length of cable, and then there are 0:20:20.480 --> 0:20:23.240 other things that come into play when you're talking about 0:20:23.280 --> 0:20:26.480 cable that happens to be under the water. But under 0:20:26.480 --> 0:20:31.240 most circumstances, even a great electrical conductor has some level 0:20:31.320 --> 0:20:34.639 of resistance. Now I say under most circumstances, because as 0:20:34.680 --> 0:20:39.720 it turns out, if you're able to super cool a conductor, 0:20:40.080 --> 0:20:42.199 like a good conductor, and you're able to get it 0:20:42.240 --> 0:20:45.840 down to an incredibly low temperature, like just a few 0:20:46.320 --> 0:20:50.439 units of kelvin above absolute zero, then you can have 0:20:50.480 --> 0:20:55.159 a superconductor which has no resistance. But under most normal conditions, 0:20:55.440 --> 0:20:58.360 you know, conductors have resistance to electricity. You can think 0:20:58.359 --> 0:21:01.640 of electrical resistance as kind of being like friction. It's 0:21:01.680 --> 0:21:06.680 working against or resisting the flow of electricity. So resistance 0:21:06.720 --> 0:21:11.040 depends upon a few different factors, such as the material itself, 0:21:11.080 --> 0:21:13.439 like some conductors are better than others, like coppers a 0:21:13.600 --> 0:21:17.400 really good conductor, and it also depends upon the thickness 0:21:17.400 --> 0:21:21.200 of that material. A thin copper wire has a greater 0:21:21.280 --> 0:21:26.200 electrical resistance than a thick copper cable for example. Well, 0:21:26.320 --> 0:21:31.159 resistance means that as you transmit electricity across this conductor, 0:21:31.720 --> 0:21:36.120 you'll see the electrical energy diminish over distance. And we 0:21:36.200 --> 0:21:39.760 know that energy can be neither created nor destroyed, right, 0:21:39.840 --> 0:21:43.520 so we're not destroying that energy. However, that energy is 0:21:43.560 --> 0:21:46.399 converting from one type to another. In this case, the 0:21:46.440 --> 0:21:50.080 resistance causes the conductive material to heat up and we 0:21:50.200 --> 0:21:53.280 lose some of that electrical energy in the form of 0:21:53.320 --> 0:21:58.360 waste heat. So if you want to push electricity further 0:21:59.200 --> 0:22:02.080 down a trans mission line, you really have to use 0:22:02.160 --> 0:22:05.720 a lot of voltage. And remember voltage is the pressure 0:22:05.840 --> 0:22:09.520 in this system. So with alternating current, we can actually 0:22:09.600 --> 0:22:14.160 use devices called transformers, which, while they are not robots, 0:22:14.200 --> 0:22:17.480 they are arguably more than meets the eye. If you 0:22:17.520 --> 0:22:20.280 were to look at an electrical transformer, like open up 0:22:20.280 --> 0:22:22.040 a cover, and by the way, never do that, but 0:22:22.080 --> 0:22:25.000 if you did do that, you would see that consists 0:22:25.160 --> 0:22:29.160 of two coils of conductive wire wrapped around a core, 0:22:29.440 --> 0:22:33.240 usually a ferro magnetic iron core in a simple transformer, 0:22:33.320 --> 0:22:37.120 not necessarily a solid core, but a core. So passing 0:22:37.119 --> 0:22:41.320 electricity through one coil of this wire induces electricity to 0:22:41.359 --> 0:22:44.639 flow through the other. We already talked about inductance, right, 0:22:45.320 --> 0:22:49.439 and the number of turns in each coil determines a 0:22:49.760 --> 0:22:53.240 change in voltage. So let's say we've got coil number one, 0:22:53.359 --> 0:22:55.880 which will call the primary coil. This is the coil 0:22:55.880 --> 0:22:59.879 where we're going to send electricity through the wire. Let 0:23:00.040 --> 0:23:04.440 say that primary coil has five turns and coil number two, 0:23:04.480 --> 0:23:08.720 which is our secondary coil, has ten turns. Well, then 0:23:08.760 --> 0:23:12.800 the ratio of turns is one to two, one for primary, 0:23:12.800 --> 0:23:16.200 two for secondary, and the voltage of the second coil 0:23:16.240 --> 0:23:19.439 will be double that of the first coil. This is 0:23:19.640 --> 0:23:23.360 a step up transformer. We're stepping up the voltage. We're 0:23:23.359 --> 0:23:26.280 increasing it by a factor of two. Now, if the 0:23:26.320 --> 0:23:29.800 primary coil has ten turns and the secondary coil has 0:23:30.080 --> 0:23:33.720 five turns, that's a two to one ratio. That means 0:23:33.720 --> 0:23:36.320 the voltage of the second coil will be half that 0:23:36.440 --> 0:23:39.800 of our first coil. This is a step down transformers. 0:23:39.800 --> 0:23:45.000 So using this we can then push voltage up on 0:23:45.160 --> 0:23:49.399 terrestrial power lines that are using alternating current. Again, this 0:23:49.480 --> 0:23:53.480 only works with alternating current, not direct current. Then you 0:23:53.520 --> 0:23:57.640 can increase the voltage for long distance transmission. You can 0:23:57.760 --> 0:24:03.240 overcome the problem of loss due to resistance. Essentially, you've 0:24:03.280 --> 0:24:05.760 just you turned the pressure on so much that it's 0:24:05.840 --> 0:24:08.919 it's powering through that. Now you have to have the 0:24:09.000 --> 0:24:11.199 right kind of cables to make that happen. You have 0:24:11.240 --> 0:24:13.800 to have the transformers along the way, and you have 0:24:13.880 --> 0:24:17.359 to step down the voltage before you feed that current 0:24:17.480 --> 0:24:21.679 into say a business or a house. But it's entirely 0:24:21.680 --> 0:24:28.600 possible to send electricity long distances overground using transformers. Anyway, 0:24:28.760 --> 0:24:32.040 it's one thing to have a transformer above the waves. 0:24:32.400 --> 0:24:35.040 If you've ever been around when a transformer blows out, 0:24:35.119 --> 0:24:39.840 you know that this is a spectacular and often terrifying event. 0:24:40.200 --> 0:24:42.880 There's a very loud boom, and it's like a thunderclap 0:24:43.000 --> 0:24:45.760 or a shotgun going off, and then there's a shower 0:24:45.760 --> 0:24:48.320 of sparks, and then all the power goes out and 0:24:48.359 --> 0:24:53.280 it happens like in that order instantaneously. It seems now 0:24:53.320 --> 0:24:57.840 that is inconvenient here upon the surface world, but below 0:24:57.880 --> 0:25:00.720 the waves that would be much worse. So we have 0:25:00.800 --> 0:25:04.560