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Speaker 1: tech Style from how stuff works dot com. Hello again, everyone,
Speaker 1: Welcome to tech stuff. My name is Chris Poulette and
Speaker 1: I am an editor at how stuff works dot com.
Speaker 1: Sitting across from me as usual as senior writer Jonathan Strickland.
Speaker 1: Have I got this straight? Jonesy? A forty million dollar
Speaker 1: computer tells you you're chasing an earthquake, but you don't believe,
Speaker 1: and you come up with this on your own. That
Speaker 1: had a direct burying to our topic today, and that
Speaker 1: topic would be sonar sound navigation and ranging. Well, that
Speaker 1: pretty much covers it, so, well, that's exactly what it is.
Speaker 1: It's one of those nice, nice words that sort of
Speaker 1: covers it. So yeah, no, it's it's it's very it's
Speaker 1: very much exactly what sounds like. It's using sound to
Speaker 1: navigate and to to find the distance from other objects.
Speaker 1: As it turns out, there a lot of ways to
Speaker 1: use sonar um and we'll get into that, uh in
Speaker 1: a minute, but there are also a lot of different
Speaker 1: types of applications, uh, different ways to use it as
Speaker 1: in like um, different kinds of equipment that that can
Speaker 1: be used to find depth and identify things in the
Speaker 1: water and even map the sea floor if you want
Speaker 1: to do that. Yep. And uh, actually, the you know,
Speaker 1: we're not the only ones to to use sonar, not
Speaker 1: by a long shot. True. Dolphins and whales use it
Speaker 1: to man to other animals. Yes, that would be an echolocation, Yes, yeah, exactly.
Speaker 1: That's what the sonar is based off of. It's the
Speaker 1: idea of the way sound travels. And so if you
Speaker 1: sound travels and waves, it's a it's actually a physical
Speaker 1: uh thing. It's you know, we don't see it, but
Speaker 1: it is a physical effect. When you make a sound,
Speaker 1: you are causing stuff to bang against each other. Sounds
Speaker 1: so so scientific, it's true. So when sound travels, it's
Speaker 1: really lots of air molecules bouncing against each other until
Speaker 1: well really just until it disperses, so it keeps on going.
Speaker 1: I mean. And we detect sound, of course through hearing,
Speaker 1: but there are other ways to detect it. There there
Speaker 1: are sounds that are outside of our range of hearing
Speaker 1: that we can sense, Like there's some that are so
Speaker 1: low that you know, you can't hear it. But you
Speaker 1: can feel it. That's thrumbing feeling. And when sound hits
Speaker 1: a really solid object, uh, it bounces it, it refracts
Speaker 1: off as some of it reflects back and uh and
Speaker 1: that's where we get the whole echo effect. So when
Speaker 1: you're in the right kind of environment and you speak
Speaker 1: and you hear that echo, that's those sound waves bouncing
Speaker 1: back and coming back to you. Well, you can use
Speaker 1: this to find your way around an environment. Well, um,
Speaker 1: so where does sonar come from? Then we have to
Speaker 1: figure out exactly. Uh really when that all started taking place,
Speaker 1: And I think it was really probably, I mean, people
Speaker 1: have been doing it for a long time. Yeah, you could,
Speaker 1: you could identify things and under the surface of the water.
Speaker 1: But why are you creating him? Because my favorite man
Speaker 1: of all time did some experiments with listening to sound
Speaker 1: through water. Okay, Leonardo da Vinci. We just finished talking
Speaker 1: about him a second ago, which I'll try and make
Speaker 1: sure that the podcast published in the right order. But no,
Speaker 1: Leonardo da Vinci back in experimented with with listening to
Speaker 1: sounds through water. He would in sort a tube into
Speaker 1: into water and put his ear to the two like
Speaker 1: a straw. Yeah, pretty much like a straw larger than
Speaker 1: a straw. Mr da Vinci, why are you listening to
Speaker 1: your drink if you had a drinking problem. So, but yeah,
Speaker 1: he would use this to to kind of listen to
Speaker 1: UH to the two noises, with the idea that if
Speaker 1: you could create the right system, you would be able
Speaker 1: to detect when things were approaching through the water. Now,
Speaker 1: during da Vinci's time, this wasn't really that big a problem.
Speaker 1: Things usually approached on the water, and if they were
Speaker 1: in the water, they weren't really something you needed to
Speaker 1: worry about. The UH frogmen of his day not not
Speaker 1: so effective. But getting all the way up to the
Speaker 1: eighteen or the nineteenth century, rather the eighteen hundreds, UH,
Speaker 1: you started to some some lighthouses would have underwater bells
Speaker 1: that would be UH placed around the area to warn
Speaker 1: ships of of hazards. So ships could actually listen as
Speaker 1: they approached land and they heard bells, they knew they
Speaker 1: were coming up on shoals, and they could they could
Speaker 1: alter their course before running aground. And then UH in
Speaker 1: around nineteen six, UH was an early passive sonar system.
Speaker 1: Will explain what that means UH in a minute. But
Speaker 1: they were using strings of microphones towed by ships, which
Speaker 1: is again something that dates up to the present and
Speaker 1: different form, but by en um and of course thinking
Speaker 1: back on it, that's you know, world War One, the
Speaker 1: British and American scientists had developed an active sonar system. Um.
Speaker 1: You know that that was a big concern at the
Speaker 1: time because of course the German uh U boats were
Speaker 1: patrolling and it was some scary stuff. Yeah, actually it was.
Speaker 1: It was a very intimidating weapon, definitely. I mean there
Speaker 1: had been some sorry I keep kinding, so there had
Speaker 1: been submarines before that, but sure, but the German U
Speaker 1: boats in World War One were a very effective way
Speaker 1: of taking control of the Atlantic Ocean and the shipping
Speaker 1: back and forth between the continents. So sonar was something
Speaker 1: that they were very rapidly trying to work out exactly.
Speaker 1: And it's funny because well not funny, but it's it's
Speaker 1: interesting to me that really the the event that kind
Speaker 1: of started all this off wasn't World War One, because
Speaker 1: by then they they were pretty far into it. But
Speaker 1: they did have an interest, yes, yes, to talk about
Speaker 1: to talk about how this really started off. You really
Speaker 1: got to look back to a certain event that happened
Speaker 1: in nineteen twelve. What was that event, Well, there was
Speaker 1: a little boat that happened to sink. Yeah, that little boat. Yeah, yeah,
Speaker 1: don't let go, um my heart will go on. Yeah,
Speaker 1: the Titanic disaster. Titanic disaster. Following that, that's when we
Speaker 1: saw the first patent for underwater echo ranging demands. So
Speaker 1: that was that was where the first patent was filed
Speaker 1: UM and it was filed at the British Patent Office
Speaker 1: by Lewis Richardson, who was a meteorologist UM and he
Speaker 1: had come up with this idea of creating a way
Speaker 1: to locate objects underwater using sound. You would you would
Speaker 1: fire sound out, you would measure the sound that comes back,
Speaker 1: and through that you would figure out what was there,
Speaker 1: how far away it was, whether it was moving or not.
Speaker 1: I mean, these were all the concepts now back in
Speaker 1: nineteen twelve, they didn't really have a way of achieving this.
Speaker 1: He panted to the idea, but it wasn't until like
Speaker 1: Chris said, around nineteen eighteen that we started to really
Speaker 1: see accelerated development because then you had a wartime use
Speaker 1: for it, and it was really important to find a
Speaker 1: way to to detect those submarines those U boats. Yeah,
Speaker 1: icebergs were were obviously concerned, especially in the North Sea
Speaker 1: and areous like that. UM because you know, as as
Speaker 1: is in the case of many cliches, there is an
Speaker 1: element of truth in it. The tip of the iceberg
Speaker 1: really is, you know, the smallest part, and so much
Speaker 1: of it is underwater, and you can't tell without some
Speaker 1: kind of device, and I think that's uh. The earliest,
Speaker 1: earliest sonar or the earliest echolocation devices were not very precise.
Speaker 1: In fact, they were so imprecise that they could tell
Speaker 1: you that there was an iceberg, but could not tell
Speaker 1: you where the iceberg was, So you you might know
Speaker 1: that there's an iceberg somewhere within a two mile radius
Speaker 1: of your ship, which is not entirely helpful, although I
Speaker 1: guess it tells you to keep an eye out so
Speaker 1: that you you don't see it before you hit it.
Speaker 1: You know, you you know, to keep an eye out
Speaker 1: for for icebergs. UM. By the by the time World
Speaker 1: War two came around, that's when the because early sonar
Speaker 1: was really led by the British, they made the biggest
Speaker 1: advances in sonar technology. They didn't call it sonar, they
Speaker 1: called it as DICK A S D I c UH
Speaker 1: and UH. The A S D was actually a code.
Speaker 1: It was it was so that the people outside of
Speaker 1: the top secret development wouldn't know what the scientists were
Speaker 1: working on. So people say, well, what does as DICK
Speaker 1: stand for? Well, it kind of stands for keep your
Speaker 1: nose out of it MR. So it wasn't really until
Speaker 1: World War Two that the United States actually outpaced the
Speaker 1: British in this technology. And uh, and that's when you know,
Speaker 1: the term sonar started to pop up, and that eventually
Speaker 1: became the de facto term for the technology. Right right now,
Speaker 1: we should probably uh at this point go into the
Speaker 1: two basic, very very very basic types of sonar, so
Speaker 1: active and passive. Active and passive, And I think passive
Speaker 1: is the easiest one to explain. Yes, basically, you're receiving
Speaker 1: the sounds of the water around you. You're listening, yes,
Speaker 1: so simply listening. So passive passive sonar is where you
Speaker 1: have some sort of sound collection device, usually a hydrophone,
Speaker 1: which is just a microphone that you can use in
Speaker 1: the water. You would have hydrophones placed and you may
Speaker 1: have a couple of different passive sonar stations so that
Speaker 1: you have hydrophones directed in specific areas, so that way
Speaker 1: you can tell where the sound is coming from, not
Speaker 1: just that there is sound, and you listen carefully for
Speaker 1: any kind of indication of other activity in the water.
Speaker 1: And it's interesting because as I was doing my research,
Speaker 1: I discovered that that if you were a trained sonar operator, yes,
Speaker 1: and you heard a submarine. Let's say you're in a
Speaker 1: submarine and you heard another submarine, right, you could actually
Speaker 1: identify where that submarine what was from, based upon the
Speaker 1: sound you heard. Yes, that is correct, it is. That
Speaker 1: is to me as phenomenal. Well, every uh, as I
Speaker 1: understand it, every ship of any kind, submarine or ship
Speaker 1: or you know, I guess boat, depending on what's on
Speaker 1: the boat has its own audio signature. Could be the engines,
Speaker 1: um or basically anything that's going on, if they are
Speaker 1: electronics on board that make a noise, if you know, fans,
Speaker 1: things like that. Some those things can help identify um
Speaker 1: another vessel in the water to the listening vessel. Yeah.
Speaker 1: For example, in the United States, most of the submarines
Speaker 1: were operating on a sixty hurts alternating current power system,
Speaker 1: but in Europe they were operating on fifty hurts power systems,
Speaker 1: So just the the frequency of the sound would be
Speaker 1: enough to indicate to you whether you were listening to
Speaker 1: a US ship or a European ship. And uh, you
Speaker 1: couldn't necessarily if everything was running the way it should,
Speaker 1: you might not hear anything at all, or you might
Speaker 1: hear very little. Um. It was if you didn't sound
Speaker 1: proof all of your equipment, like if if the various
Speaker 1: elements weren't uh weren't insulated properly, then stuff would rattle
Speaker 1: and you could you could actually hear the rattling. In fact,
Speaker 1: one source I read said that, uh, you know, the
Speaker 1: location of a submarine might be given away by someone
Speaker 1: accidentally dropping a wrench onto the floor the deck. I guess, um,
Speaker 1: I assume they're decks and submarines. I've never been a
Speaker 1: board one. Yes, so yes, if you were to drop
Speaker 1: a wrench to the deck, it could create a sound
Speaker 1: that someone another sonar operator might be able to pick
Speaker 1: up and say, all right there there support. Um, so
Speaker 1: it's it's a pretty interesting thing. And passive sonar, by
Speaker 1: the way, was more important for submarines because if they
Speaker 1: use the active method, they would actively be giving away
Speaker 1: their location. Yes, that's because active active sonar systems are
Speaker 1: giving off a pulse of sound yea often called a ping. Yes,
Speaker 1: So you ping the sound out and uh, and then
Speaker 1: they wait for the sound waves to come back. And
Speaker 1: based upon how long it takes uh and how much
Speaker 1: how strong the signal is, that's how you kind of
Speaker 1: determine what it is your your hearing or you know,
Speaker 1: how far away the the object is and you know
Speaker 1: what it might be. You know, how many how many
Speaker 1: submarine movies have you seen where they do that tense
Speaker 1: moment where nobody's moving a muscle they got wait wait,
Speaker 1: you know, and there's just like you know, you watch
Speaker 1: the beads of sweat rolled down the submariners faces. Yes,
Speaker 1: there's the there's the one that I quoted at the
Speaker 1: beginning of this podcast. Um, yeah, no, no that, but
Speaker 1: there are many you know that that. And that's the
Speaker 1: thing is you have to be very very quiet and
Speaker 1: that kind of a situation because any little thing can
Speaker 1: be up by the ping. And here's what's really interesting
Speaker 1: to me is that the ping is well really anything
Speaker 1: could be picked up by passive sonar. I know, I
Speaker 1: just want to make it okay, I got you. I
Speaker 1: was about so active, but with you stopped at one
Speaker 1: of three the active sonar. The basis of that really
Speaker 1: rests in the fact that we know how fast sound
Speaker 1: travels through water. But we we do, but it's really complicated.
Speaker 1: You would think, oh, it's got to be some constant right,
Speaker 1: not exactly actually constantly constant. Yeah, The speed of sound
Speaker 1: traveling through water depends on several things. Depends on the
Speaker 1: temperature of the water, the salinity of the water, and
Speaker 1: the depth of the water, and all of these things
Speaker 1: affect the density of the water. Which makes sense, right.
Speaker 1: If you've got more molecules packed together, sounds going to
Speaker 1: travel faster through that because the molecules hit each other
Speaker 1: more quickly, Like it doesn't take much for a molecule
Speaker 1: they'll run into another molecule. The sound travels much much
Speaker 1: further and much faster. Um if you've got them spread out,
Speaker 1: then they lose some of their energy as they are moving,
Speaker 1: and so it doesn't travels far and it doesn't travels quickly.
Speaker 1: So the rule of thumb is that it's four thousand,
Speaker 1: three eight feet per second. And then you have to
Speaker 1: add all these modifiers in right right now, there are
Speaker 1: some some things that you can do. Uh. There is
Speaker 1: a system that I read about, the a n B
Speaker 1: q H DASH one speed of sound measuring system, which is,
Speaker 1: you know, a modern sonar system. Um. But it evaluates
Speaker 1: the depth and temperature and salinity of the water to
Speaker 1: get an idea of how the speed of sound is
Speaker 1: going to travel through that particular water at the time. Obviously,
Speaker 1: that's probably a very expensive piece of equipment because it's
Speaker 1: doing those calculations for you. But that's what modern computing
Speaker 1: technolo gets you. Um. But yeah, it gives you uh,
Speaker 1: you know, sonar technicians can use that equipment to get
Speaker 1: an idea of what's going on with a lot better accuracy,
Speaker 1: and also helps them avoid being detected by other sonar
Speaker 1: equipment because they have an idea of you know, what's
Speaker 1: the current conditions are underwater where they are right. So
Speaker 1: if you're using active sonar, you might be using it
Speaker 1: for uh. Well if in wartime you would have ships
Speaker 1: and and even aircraft using active sonar to try and
Speaker 1: detect submarines and then drop depth charges down to to
Speaker 1: disrupt the submarines. Ah, yes, uh, so active sonar in
Speaker 1: wartime is often used by by vessels that can move
Speaker 1: fast enough so that it's not it's not a big
Speaker 1: deal about giving away your location like destroyers for example,
Speaker 1: exactly exactly, if you're a submarine, you don't tend to
Speaker 1: use active sonar as often. Um Yeah, especially when you're
Speaker 1: submerged in trying to avoid detection, because that's you can't
Speaker 1: move nearly as quickly as a the enemy destroyer you're
Speaker 1: coming after you. Right, So so if you're also you
Speaker 1: could be using active sonar, not just in wartime, but
Speaker 1: also if you're mapping the ocean floor, then you want
Speaker 1: you want to be as accurate as possible, which means
Speaker 1: you have to have you know, you have to factor
Speaker 1: in all those elements we were talking about before, the
Speaker 1: salinity and temperature and depth and all that. Um. If
Speaker 1: you if you're just using sonar as a fish finder,
Speaker 1: because there are plenty of products on the market that
Speaker 1: do that, you don't have to worry quite that level
Speaker 1: of accuracy because you're not you're usually not talking about
Speaker 1: the same kind of distances involved that we're talking about,
Speaker 1: and usually the you know, the depth is not as
Speaker 1: big a factor. So really in that case, uh, you know,
Speaker 1: you could use a constant speed for the sound through
Speaker 1: water and not be so inaccurate. You're looking for schools
Speaker 1: of fish. You're going to be moving around anyway, so
Speaker 1: it's not like it's um, it's not like the kind
Speaker 1: of precision work you need to do with these other elements, right.
Speaker 1: Actually that that's one of the things that I found
Speaker 1: fascinating during part of the the sent our Technicians training.
Speaker 1: They actually uh are known to record things that are
Speaker 1: just natural sounds, like the sounds of fish, um, tectonic plates.
Speaker 1: I'm not sure. I'm not sure what kinds of sounds
Speaker 1: does give off really low, low groaning ones. Yes, my back,
Speaker 1: but that's but that's the the trick is you once
Speaker 1: they understand what those things are, they can eliminate them.
Speaker 1: They go, oh, well, that's just a large school of fish,
Speaker 1: you know. Oh that's you know, an alien spaceship that's
Speaker 1: crashed underwater, that kind of stuff. Um, I make a joke,
Speaker 1: but no, that that that Uh. I was wondering about
Speaker 1: that when I was reading about civilian uses for so
Speaker 1: in our technology and I was thinking, Wow, how do
Speaker 1: they know, you know, what is a school of fish?
Speaker 1: And obviously if you're on a lake and it's it's
Speaker 1: probably going to be the stuff that's moving around underwater.
Speaker 1: It's not likely to be in any submarine. But you know,
Speaker 1: detecting a fish versus you know, a snake or some
Speaker 1: other type of nest monster. We've gotten very silly, very quickly.
Speaker 1: Well no, I mean people have been using that kind
Speaker 1: of equipment to try and determine whether or not there Yeah,
Speaker 1: so in our equipment. Yes, there are plenty of monster
Speaker 1: hunters who have tried to use like a fish finder, yeah, essentially.
Speaker 1: But that's the thing is that there there are schools
Speaker 1: of fish in Lockness and schools of eels as well.
Speaker 1: So you get a school of fish or a school
Speaker 1: of eels that's going to give you a reading. And
Speaker 1: then people say, hey, look there's a monster down there.
Speaker 1: Not necessarily, And I have to say, you know, I've
Speaker 1: mentioned before in the podcast that I'm a skeptic. Out
Speaker 1: of all the things to be skeptical about, the lucknest
Speaker 1: monster was the one I held onto the longest because
Speaker 1: I want to believe it's real. I don't believe it's real,
Speaker 1: but I want to so badly. Um, in a cottage
Speaker 1: on the shore, there's a shadow on the door. No
Speaker 1: different kinds of sonar like side scan sower. UM. This
Speaker 1: is a device used to find objects on the sea
Speaker 1: floor and figure out what they are. UH. They usually
Speaker 1: have a toe fish or a toebody, which is a
Speaker 1: UM basically a sophisticated device that goes in the water
Speaker 1: and is towed behind the ship, and UH a device
Speaker 1: that processes the signals on the top. UM. What happens
Speaker 1: is they used the the sound energy which is transmitted
Speaker 1: in a fan shaped pattern and UH goes about a
Speaker 1: hundred meters down or so. Basically they used the information
Speaker 1: that comes back to create a an image of what's
Speaker 1: on the sea floor. So if they get a really
Speaker 1: strong signal UM back, that appears as a light image
Speaker 1: on the screen, whereas weaker signal would show darker images.
Speaker 1: So UH sort of a black and white image. I
Speaker 1: don't know if it's actually black and white because I
Speaker 1: was reading copy and they didn't bet but i'd be
Speaker 1: bright green and dull, right right. But you can get
Speaker 1: an idea of what the bottom of the area you're
Speaker 1: looking at. I guess it could be a lake or
Speaker 1: the ocean. UM. They don't they don't offer the same
Speaker 1: kind of depth information as the military would use to say, oh, well,
Speaker 1: we you know, we're about to run aground. It's not
Speaker 1: the same kind of application of sonar. Also, we should
Speaker 1: add that at certain depths, once you get really really deep,
Speaker 1: the water gets so dense that it can refract sound waves.
Speaker 1: So you you start to lose the ability to really
Speaker 1: map the ocean floor with sound because the water itself
Speaker 1: is so dense that it's it's it's mucking things up. Also,
Speaker 1: I guess I should go ahead and mention as well.
Speaker 1: We've talked a lot about the sonar. The sonar really
Speaker 1: has three main elements to it. Oh, yes, there's a
Speaker 1: transmitter which transmits the sun right right right. I can't
Speaker 1: believe we didn't. We didn't really talk about it. But
Speaker 1: there's a transmitter that's that's what passes on the signal. Uh,
Speaker 1: it's an electric signal that goes to a transducer. Now,
Speaker 1: transducers what they do is they convert one kind of
Speaker 1: energy into another kind of energy. In the case of sonar,
Speaker 1: it's converting sound electricity rather into sound right. Active for
Speaker 1: this is for active sonar, clearly. And then you've got
Speaker 1: a receiver that receives the signals when they come back
Speaker 1: um and and then you usually have a display, so
Speaker 1: there's a transmitter, transducer and receiver. This is for again
Speaker 1: active sonar. With the passive sonar, you just need receivers
Speaker 1: really microphones, hydrophones, UM and and there are plenty of
Speaker 1: stationary UH sonar UH stations and I guess stationary stations,
Speaker 1: thank you, Jonathan, you're both repetitive and redundant. But at
Speaker 1: any rate, there are plenty of these in the ocean.
Speaker 1: The lots of different militaries have them station stationed at
Speaker 1: different spots along the coast to detect things like possible
Speaker 1: incoming submarines, that kind of thing. UH. And I wanted
Speaker 1: to mention very quickly about an interesting sound that was detected.
Speaker 1: Oh do you want to? Yes, I do, I definitely
Speaker 1: want to. There was a sound detective in It was
Speaker 1: actually detected several times over the summer of U in
Speaker 1: the Pacific Ocean by by a hydrophone array. And the
Speaker 1: sound was a very low frequency sound generated over a
Speaker 1: pretty extended UH time frame several I think it's several
Speaker 1: minutes long. And it's called the bloop. The bloop is
Speaker 1: UM this odd sound that that we're not really sure
Speaker 1: what made this noise. If it was organic, then it
Speaker 1: would have to be a creature larger than any that
Speaker 1: we've previously identified. So if it were a whale, it
Speaker 1: would have to be such an enormous whale that we've
Speaker 1: never seen it. Uh ever, yeah, so be be ginormous,
Speaker 1: right to use the technical term. It's more likely that
Speaker 1: the blue is a h was some sort of geological byproduct, right,
Speaker 1: But at any rate, this sound was located or the
Speaker 1: location of the sound is probably somewhere around fifty degrees
Speaker 1: south hundred degrees west. What's interesting to lovecraft Ian fans
Speaker 1: is that that's not that far off from the supposed
Speaker 1: coordinates of Realier, which is Cathulu's city of the Deep.
Speaker 1: So some people have jokingly, tongue in cheek, said that
Speaker 1: this noise was dead Cathulu snoring because in his house,
Speaker 1: and really a dead Cathulu lies dreaming. Alright then, and also,
Speaker 1: let's some we can actually play the sounds. So what
Speaker 1: we're gonna do here is we're gonna just take a second,
Speaker 1: we're gonna play the sound. This is a sound that's
Speaker 1: off of the U. S. Government's websites, and it is
Speaker 1: specifically the sound sped up sixteen times. Now, I don't
Speaker 1: know about you, but I think that was Catlu. I
Speaker 1: was pretty certain it was a bunch of people flushing
Speaker 1: all at the same time. Could have also been that
Speaker 1: it might have been during the Super Bowl. Wait, it
Speaker 1: was the summer of ninety seven, so it couldn't have been.
Speaker 1: I don't know anything about sports, but even I know
Speaker 1: it doesn't happen in the summer. It was World Cup.
Speaker 1: It was a World Cup, except that wouldn't have been
Speaker 1: It wouldn't have been a World Cup. Okay, so our
Speaker 1: speculation goes awry. Also, we had someone on Facebook I think,
Speaker 1: asked us about the blue Yes, there that goes and
Speaker 1: that goes out to you random Facebook person. All right, UM, so, uh,
Speaker 1: you know, I did look up some other interesting related
Speaker 1: technology like LDAR, which is a light detected light detection
Speaker 1: and ranging system doesn't use sound, uses light, but it
Speaker 1: is used. Bath Memetric lighter is used to determine the
Speaker 1: depth of water. UM. It uses lasers, pulses of lasers
Speaker 1: sent out at two frequencies. UM. There's an infrared pulse
Speaker 1: which is a lower frequency and then reflects off the surface,
Speaker 1: so you know where the surface of the water is
Speaker 1: and then it uses green lasers that have a higher
Speaker 1: frequency that reflects off the bottom of the area. Interesting,
Speaker 1: and it works pretty similar to echolocation because it's getting
Speaker 1: a reading for the top and the bottom of the depth,
Speaker 1: so you can get an idea of how deep the
Speaker 1: water is. And they use this um from aerially generally,
Speaker 1: well from they're mounted on aircraft. UM so according to
Speaker 1: Noah and I mean the National Oceanic and Atmospheric Administration,
Speaker 1: not the guy with the big boat. That's the second
Speaker 1: time you've made that joke on this pod, not this
Speaker 1: particular episode, but in the series. Yeah, well you know,
Speaker 1: but yeah, and depending on how clear the water is,
Speaker 1: they can determine depths up to fifty meters And this
Speaker 1: is really useful for those, uh, really hazardous areas where
Speaker 1: it's might be difficult to get a reading from a vessel,
Speaker 1: a waterborne vessel. It would be dangerous to put a
Speaker 1: ship there, exact reefs and shoals and that sort of thing,
Speaker 1: which is exactly why you'd want to know what it's like,
Speaker 1: you know, underneath the surface of the water, so you
Speaker 1: can get an idea for navigation purpose. I mean, really,
Speaker 1: sonar just don't mean to interrupt. But the reason why
Speaker 1: sonar it was so important early on is because light
Speaker 1: does not travel through water very well. It's just normal light,
Speaker 1: and you know, you go down just a couple hundred
Speaker 1: feet and it's it gets dark really fast. And anybody
Speaker 1: who's swam in the Atlantic Ocean knows that it's not
Speaker 1: exactly the clearest water. Uh So it will be especially
Speaker 1: difficult to see in in you know, water with a
Speaker 1: lot of salinity and trabidity. And of course if you
Speaker 1: get it at pretty intense depths, then you don't want
Speaker 1: to have any windows in your device at all because
Speaker 1: the pressure is too great. Um. Before we get to
Speaker 1: the next segment, I was going to mention too that
Speaker 1: you can you can actually sonar from uh you know,
Speaker 1: from the air as well, if you're using a sona buoy,
Speaker 1: which is basically a buoy that is equipped with sonar
Speaker 1: equipment that is lowered I guess by a helicopter would
Speaker 1: probably be the best. Uh that's where I've actually seen
Speaker 1: it done, where they lower it into you know, so
Speaker 1: there's floating on the surface of the water that they
Speaker 1: can get readings um from anything that might be in
Speaker 1: the area. Yeah, that's pretty cool. That's often used in
Speaker 1: in wartime as well, because it's a way for you know,
Speaker 1: you send a helicopter out to the general region where
Speaker 1: you believe there's a submarine. You use these to try
Speaker 1: and locate the submarine. Then you use the depth charges,
Speaker 1: which are really just explosives that that sink into the
Speaker 1: water before exploding. UM, and then try to damage or
Speaker 1: or disrupt the submarine in some way whereas the submarine
Speaker 1: is trying desperately to or the people in the submarine anyway,
Speaker 1: or trying desperately to avoid detection. Or sometimes they'll use
Speaker 1: things like UM decoy explosions. So you create enough uh
Speaker 1: noise in the water and it becomes very difficult to
Speaker 1: pinpoint a specific object. UM. And I know you wanted
Speaker 1: to discuss that it's not all the sonar is not
Speaker 1: all necessarily beneficial, that it can actually have a negative
Speaker 1: impact on the environment. Right, we're actually the creatures living
Speaker 1: in the environment. We mentioned that that whales and dolphins
Speaker 1: use echolocation in order to navigate their environments. UM. Sometimes
Speaker 1: there have been reports that that the low frequencies used
Speaker 1: in sonar equipment have disrupted that they're this marine life
Speaker 1: that in some cases there may be instances where it
Speaker 1: has spooked a pot of whales, for example, and and
Speaker 1: and so there there's some studies that suggest that some
Speaker 1: whales are suffering from a kind of um uh well,
Speaker 1: sort of a pressurization sickness because they're surfacing so quickly
Speaker 1: that they are uh it's kind of like whales getting
Speaker 1: the bends. Yeah, actually it's exactly like wells getting the bends.
Speaker 1: Because the report I saw was actually from a uh
Speaker 1: uk organization called Marine Connection, which is a pro um
Speaker 1: uh water life organization, and they had cited a study
Speaker 1: from the magazine Nature from two thousand three which was
Speaker 1: citing an instance in which ten beaked whales uh surface
Speaker 1: too quickly off the Canary Islands um in two thousand two,
Speaker 1: and and they got the bends. The whales got the bends.
Speaker 1: And apparently the situation is especially prominent for deep diving
Speaker 1: animals such as a beaked whale. And it may be
Speaker 1: related to the terrain underneath the water. If it's really
Speaker 1: steep um sharp drop off, that may affect the way
Speaker 1: that the sound waves are traveling underwater and maybe especially
Speaker 1: confusing um. Noah also mentioned that there might be problems
Speaker 1: for deep diving species, but said that more study needs
Speaker 1: to be done on on these kinds of strandings to
Speaker 1: find out if it's limited to the surroundings, if it
Speaker 1: actually is the c floor that is playing into it,
Speaker 1: or whether it is strictly the sonar itself, you know,
Speaker 1: before they can make a decision as to what's going on.
Speaker 1: But the Marine Connection has asked the uh, um, they've
Speaker 1: actually gotten involved and suggested to the European Parliament and
Speaker 1: it asked for a ban on high intensity sonar in
Speaker 1: certain areas. Um. So you know, there there are concerns
Speaker 1: that it may cause uh some some harm basically that
Speaker 1: they can swim into uh dangerous terrain to it. That
Speaker 1: is also an issue if they're they're momentarily confused, but
Speaker 1: in dangerous waters, that could be long enough for there
Speaker 1: to be a serious problem. So yeah, there there are
Speaker 1: some concerns about this technology, which we've been using for
Speaker 1: almost a century now, uh yeah, and we're still some
Speaker 1: of them, like the passive systems. Of course, that's not
Speaker 1: a problem because the passive systems, all they're doing is listening.
Speaker 1: They're not sending out any signals, so not all sonar
Speaker 1: is bad sonar even from a marine life standpoint. Oh no,
Speaker 1: it's still an incredibly useful technology, right, you just have
Speaker 1: to learn how to use it responsibly so that you're
Speaker 1: not causing harm to the environment or to marine life
Speaker 1: in particular. Well, I guess that pretty much wraps up
Speaker 1: a discussion on sonar. This was one of the Pallette's
Speaker 1: pet pet topics. He's he likes the topic as well.
Speaker 1: I think the video series brought that out, and they've
Speaker 1: had our radar and sonar moments, so that was a
Speaker 1: lot of fun. If you guys have any suggestions for topics,
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