Listener Mail Roundup #1

you doing today? Really well, well, today, I'm very excited because we're gonna be talking about some listener requested topics. But we've really had a lot of listener requests piling up lately. Yeah, which is fantastic. Guy, We really appreciate it. So we love it. We're not complaining, but they're they're only piling because you're so fabulous. Yes, and we can only record and published two episodes a week. But so today we thought, you know what we should do, We

should do a listener mail roundup episode. Now. Unfortunately, even in this episode, we're not going to be able to get to every one of the things you all have sent us that we want to talk about, but we wanted to pick some of the topics that could be addressed in a slightly shorter form and uh and take them on all at once, and some of these may eventually become part of an episode where we take a deeper dive into these, but a lot of the questions

seem like they would have a fairly quick answer that wouldn't justify a full length episode, which is why we kind of grouped them together. They're they're not grouped by any sort of theme either, because you'll see as we go on, it's kind of all over the place, which

is cool. Yeah. Yeah, So our first listener suggestion that we want to get to today actually came to us on our Facebook while it was our listener Ed who asked us about the future of media delivery, and Ed said podcast idea, I want my MP three or LP or v O D. I think that's and I want my MTV joke for the kids who don't remember dire Straits or just MTV. Right. Ed goes on, how will we be listening to or getting our music, watching movies,

reading books and magazines and newspapers in the future. Well, I think this is a great question. It is it's a fantastic question, and it's one that I mean, if I were. If I were being snarky, I would just say streaming and move on, because I think that that's really the the answer to a lot of this, and it's an answer that's being pushed partly by consumer behavior and partly because it's a very attractive model for companies. Sure, well,

we've got the resources in place, don't we. I mean now that now that high speed internet is becoming the norm, at least in some parts of the world, and more and more of the world long term, it's kind of hard to argue against the power of streaming. Well, you have so much access and it takes up so little space,

right that. I mean, it wasn't that long ago that WiFi was really the speed you would need in order to get decent streaming experience, right otherwise it was going to be a very low quality stream or you're gonna buffer. So you know, I remember the days of trying to listen to something on streaming and get twenty seconds in and then suddenly the song stops, and you wait another

fifteen seconds, then another twenty seconds of music plays. But now now we've gotten too speeds of WiFi, we've gotten better speeds of of cellular service, and we've gotten better compression uh models for streaming media to allow that to happen where we don't have as frequent an issue with buffering still happens once in a blue moon. It happens on my my connection at home, which is pretty fast. But well, I mean, you know, you've got to have that trifecta of a device that can handle it, right,

connection that can handle it, and the actual service. Yeah, I mean if you don't have if one of those three things is deficient, you're gonna have a poor experience. But we're we've reached the point where the norm is that you can have this pretty seamlessly. Like my my phone. Now I can use my phone, uh pretty much anywhere in Atlanta, uh streaming a podcast, so I don't have

to download an episode anymore. I can just stream it and it cash is enough of the podcast in local memory so that if I do pass through an area that has uh, you know, weak service, Like you know, I often take the train. In the train here in Atlanta, there's above ground sections and below ground, so sometimes when you go below ground, you lose that connection, but the CASH corrects for that, right, it has enough in the buffer so that I can keep listening without having that interruption.

I think that because the technology has reached this point, streaming is really where a lot of this is going. It also means that we can listen or watch stuff when we feel like it. You know, we we we can. And a lot of those UH services also allow us to stop at one point and pick up at that same point even as we switch devices. So if we go from TV to phone or tablet or whatever. Yeah, I agree that digital playback is going to pretty much dominate.

It's going to be king. I can't really see that changing for any good reason except for the sort of small scale collector aspect. I personally, I listen to records at my house sometimes, and I don't know why. I guess it's just fun. It can be fun to go record shopping, to put a record on the turntable. There's something aesthetically pleasing about it. It's a fun activity. But I'd say most of my listening I do digitally, whether that's podcasts or I mean obviously for podcasts, but h

or music. Most of the movies I see now, I think come to me in a digital form. And I don't know do you'll think there's any reason that we'd see a major comeback of physical media for say music playback. Nope, m hm m m. I mean yeah, yeah, there's that that nest Alga factor and and that esthetic pleasure that you get from I mean, cassette tapes are a thing again?

Are they really a thing again? Are they? I mean, I mean I know that I know that there was the the marketing gimmick of the Guardians of the Galaxy soundtrack coming back out on cassette? Are cassettes really coming back? Bands, like, like smaller local bands are releasing some of their albums on cassette tape? You have to there's still there's still still electronics companies selling cassette tape players. You've got some

blood running down your force. Well, I mean, I'm just like, I'm like, I'm like, look, guys, we're better than that now. I've left those days behind. Cassettes are not great media formats, yeah, but they're fun. Come on stick and a lot of a lot of older cars do still have cassette decks.

I guess, so yeah, I can understand. I do agree that it's a lot easier to form kind of that emotional attached meant to uh to something when there's a physical representation of that thing, Right, Like I have a vinyl record collection, and there is a particular feeling I get when I pull an album out of that collection, put it on a turntable and listen to it. The

ritual of it is kind of lovely, exactly. Yeah, there is a ritual that's associated with it that's very comforting, and it's all part of the experience which you can't you know, you can't really place a quantitative value on, but it's certainly. Yeah, I never get that warm fuzzy when I like open iTunes, yeah, exactly. Yeah, when I when I open up my my Google radio playlist that's based off the album that I really love. Yeah, I mean,

it's not the same thing. So I don't want to I don't want to dismiss the the value of physical media, but I think that because there is the incentive on the part of the media company, these two maximize profits, which you certainly can do if you don't have to have a physical presence anywhere. You know, you don't have to create inventory, you don't have to have a place to move that inventory, you don't have to worry about inventory loss. If someone steals your physical stuff and you

can no longer sell it. I can see a lot of reasons why companies would shy away from it, and this could become something that we see more on a special case by case basis, as UH entities, whether it's an author or a band or whatever, are catering to their audience. One way I do see this changing though, is that I think laser discs are going to come back in a big way. I think capacity and electronic discs are going to come back in a big way

in the future. When you want to watch Terminator two, you're gonna get out that laser disc and you're gonna flip it halfway through the movie. Yeah, I agree with ancestors exactly. No. Actually, one thing I do want to say that I feel pretty strongly about out the future of audio playback is actually about the devices we use themselves. I think we're going to continue to see a decoupling of the audio reading device from the actual device that

produces the sound. So, for example, this this exists today. You can get pretty good Bluetooth speakers or Bluetooth headphones, so you stream audio from the Internet on your phone or your laptop or your TV, and then you listen to that audio through whichever speaker system phone connects to a speaker system, and yeah, you seek to your player, the headphones, the whole speaker system, and you know, that's bye bye to the earbuds with the chords. I think

that's going to become pretty universal. Sure. I mean, I have a I have a pair of I have a Bluetooth headset that's meant for music and podcasts, that sort of thing that uses bone conduction as well, so it's not even over the ear, but it also doesn't have to doesn't have a chord or anything. I definitely see that trend continuing. Oh sure, sure. Uh you know, I think as the technology improves, probably your big clunky headset or small, sexy, slim headset will be the device that

is streaming the media directly. Uh yeah, And I just see generally more ease of interconnectivity. So like as we have the Internet of Things entering our homes, more devices will be the sort of the digital basis of playback, and then you can sink them to whatever kind of

thing it is that's making the actual noise. Well yeah, again, this this kind of comes back to the idea of Let's let's use Netflix as an example, where if I'm watching I'm logged into my Netflix account, and I'm watching Netflix on my phone, and then I go into my house and I want to turn on that same movie using a set top boxes connected there that's logged into my account as well. So when I started, it picks up where I left off on my phone. This uninterrupted

experience is also something I see continuing in to the future. Uh. The interesting thing to me is that if you had asked me, maybe I don't know, five or six years ago, I would have thought that the standalone MP three player would still remain king because back back then streaming was not really the method you would download, and so you would keep everything on the memory of the device itself

instead of it being cloud based. And I would have said, this is how it's going to continue for the foreseeable future. And in fact, for the longest time I carried an MP three player and a phone because I didn't want to clog up my phone's memory with media. I still do have an MP three player in a phone. I've graduated.

I only go phone now because I use this streaming method, so I'm not filling up my memory, the cash fills up so that if I do lose that connectivity, I can continue enjoying whatever it is I'm I'm listening to her, watching or reading. But it's not it's not that I need to have a phone with practically end less amounts of storage because that storage isn't needed anymore. Yeah, yeah, I do think that in general across media or going to continue to see like you know, mid sized portable devices,

whether that's a tablet or a mini tablet or um tablet. Yeah, that's what. I have very large buttons on your coat that that can play movies back to you. I don't know, um that that are right, that that are capable of handling both music and video and and books and etcetera,

and and you know, doing the streaming thing. I don't know. Like, like I wonder, I wonder whether at a certain point when if like memory will become cheap enough that people will return to I mean, it depends if the if the service ends up being so seamless that it's not necessary. I don't think it's going to be a thing, but they're always going to be times at least that I can see where you are going to want to have

things stored directly on the advice itself. For example, if you take a flight somewhere and you don't want to spring for WiFi on the flight. Plus, WiFi on flights is never at the speed that here, and I think that that's a that that's a point like like right now, um, cellular service isn't available everywhere, WiFi can be spotty, you have to pay for them in in many contexts, and so therefore streaming isn't quite ready. It's not to go

not supers totally seamless. It all depends on where you look. Like if you're in a city like Atlanta or San Francisco or New York, it's probably pretty good, but that's not universal. Yeah. I would also add to that access anxiety if you're interested in something that is perhaps obscure, something you're not sure is going to continue to be

provided by Netflix or whatever. You know, that's a good point, you think, well, you know, I don't know if this movie is still going to be on Netflix in a year when I want to watch it again, I'd rather just own the Blu Ray, right. I mean, if Tammy and the t Rex goes away, I don't know what I'm gonna do me there, and uh, what about what

about books? Right? Right? So, I think that more reading is going to be done digitally as prices on reading devices electronic reading devices drop, and I I suspect that in parallel, print prices are going to rise as printing runs get smaller as a result. I see, so you're you're thinking of because the the market is moving more digital, the the potential market for actual physical books is getting smaller.

That drives the prices up because you can no longer print in the volumes that you would before and expect a decent return on that investment. Right. The other way of looking at that is that they just keep the prices the same by cutting costs, and there will be more typos in your print books now editor free. I'm sorry, we only hired a copy editor for the digital version of Lauren. I liked your book, but the main character's name changed like six times. That was part of the point. John, Uh,

these modern novels. I'm actually I'm in thinking about this. I got the sudden moment of of worry that, um, some people might start to get priced out of easy access to print media due to the fact that, um, you know, from an entry standpoint, a paperback is a lot cheaper than a kindle and probably will continue to be. Um even though you know, obviously getting a kindle at having basically unlimited access to a lot of books for

very cheap or even free in the case of classics. UM. Well, and I love I love the move to electronic media for another reason. It also gives us access to books that otherwise have passed out of print. They're not in the public domain. You still have to buy them. But I'm the son of an author. My dad has a horror novel that came out in the eighties and it's my favorite book that my dad ever wrote. I love it.

But it's not available in physical format anymore. But you can get it electronically, and that's something that I love. It means that people can have access to works that there's no reason from the publishers standpoint to produce more. Yeah, there's not enough, there's not a large enough market to justify. But electronically you can have anything out there. Yes, yes,

and that that is truly wonderful. Um And I wonder, I wonder whether for like the generation being born right now, literally right now, I salute you, um when when you're all about to listen to this, you'll appreciate that. Yeah, what weather for them? Paper books and like paper printed magazines and newspapers are going to become a nostalgic, uh nostalgic. I don't want to say fetish, but but but but like a nostalgic uh like like like like an anachronism

some sort of like tape or a vinyl record. Yeah. Yeah, if reading something on paper is going to be like, oh, I just love the ritual of opening a book. You know, maybe this is I'm just far too technophobic, I guess to be talking about technology all the time. I do admit I have a perhaps old and preference for paper books. I don't have a tablet, but I don't think I would really like to read a book length literary work on one. I can. I'll read articles on the internet

and stuff I I I gotta. I got one of the touchscreen kindles at some point, and I actually really like it. I but but I also did get the kind of case for it. It's like made of wood and leather, and so you open it and you kind of feel like you're opening a book. Um, well, maybe

I just need to get with the times. I will say that the move to digital formats for books also means that we'll have fewer head scratching lee odd moments in movies like have you guys heard about the scene in the j LO film Boy next Door where the boy next Door hands her a quote first edition of the Iliad end quote? Well, hey, there have been lots

of first editions of the Iliad. That's the problem is that just like they're joking that it's this it's this valuable thing, or it should have been a blind poet, it should have been exactly just starts reciting in Greek. The first edition is the first time it's fixed intangible medium. Well, you know, if we go back into the brain waves thing anyway, that's that's neither here nor there. But I think I think it was great question. It was It

was interesting. Um. I do think that streaming, for at least the foreseeable feature is going to be the way to go. Maybe we'll eventually get to a point where things will get beamed directly into our brains and we will experience them instantaneously in their entirety. I hope. So that would be such a time, It would really I could get through all of those books that are on

my list in like no time flat. Yeah. Well, thanks for your question, ed. I think now we're going to move on to an email we got from our listener Jude about geothermal energy and space coordinates. So Jude says, hi, there, hey, Jude, Hey, oh no, I see what you did there. Go ahead, Jude says, hi there, I've been listening to your audio podcast. You guys are doing a great job. Thanks to that warms my my cold heart. Yes, uh, part is very warm Jack. Well, okay, sorry, back to the email. Can

you please cover the following topics. We all know Earth's core is molten rock and must be a source of massive untapped energy. Has anyone attempted to harness Earth's geo thermal energy? And how do astronomers navigating the cosmos or refer to a star object in space? Is their GPS equivalent in space? Thanks a lot from Jude in Bangalore. So we're going to take these in turn. We'll start with geo thermal So, first of all, geo thermal energy

is a thing, obviously something that we we harness. It doesn't involve tapping into the Earth's core directly, although as you'll see, there's kind of an indirect long tail version of tapping into the Earth's core. Geothermal heat means thermal energy or heat from the Earth. So that heat is generated primarily from two sore says. One is that is the radioactive decay of materials that are in the Earth's crust. That accounts for about actually of geothermal energy. Really I

did not at all. The other comes from the geothermal gradient, which is the difference between the cores temperature and the planet's surface temperature. So you probably know heat conducts from high concentration to low concentration, right, and that means that heat is moving from the core out into the crust. Uh So if you dig down far enough, the temperature starts to go up. You know, I knew that, but I had no idea how to do with this radioactive decay.

I assumed that it was because of the pressure of the rock above it. Well, radioactive decay is again just that that's part of what's generating heat, because as we've talked about before, radioactive decay that is one of the byproducts. But the actual heat from the core that has nothing to do the radio activity. That's that's just basic physics

of conduct auction. So as you drill down, that temperature goes up, and the average is twenty five to thirty degrees celsius per kilometer or fifteen degrees fahrenheit per thousand feet. That's the average, because there are some areas where that gradient is much different. For example, if you're drilling near volcano, you might notice that temperature goes way up way faster. Macma will do that to you. Uh So it's thought that this gradient actually decreases dramatically as you get through

the crust and into the upper mantle. And the basis for that hypothesis is that if it were steady, if in fact you continue to see that that rise in temperature every kilometer, then you would eventually within the lithosphere. That's the area of the upper cross, not the upper acrust, the crust, the upper mantle uppercrust is a great band um that if if that remains steady, it would eventually hit the temperature where rock would melt before you got

to a point where it's no longer solid. Like we know that the crust and upper mantle are solid and brittle, and that's below that when you start hitting liquid and then you get to the solid core, when you get to the very center of the earth. Uh. And because we know that, we know that this gradient has to level off at some point. It can't continue at that pace, or else the temperature would be too high for there to be a solid surface there or solid material there.

It have to be liquid. So this is still just a hypothesis. However, we don't really know what the actual conditions under the surface of the Earth are because we haven't had direct observation of it. Yes, spoiler alert, Jules Verne wrote fiction. Yes, did not really go to the center of the Earth. The deepest hole that humans have ever drilled is the Cola Super Deep Bore Hole in Russia. It's one of my favorite things. It is. That's a

great name for a thing. Anyway, go ahead. There's a great video that shows exactly where it Isn't It just looks like a little metal plate pipe sticking out of the ground. It's it's now, it's a metal plate on top of that pipe that is welded and bolted onto it. So you know, but it looks like you could otherwise just throw pennies down there. No, yeah, you can't. Like wait,

let's see let's listen for the drop. So this thing is super deep, as the name implies, well if thou actually doesn't imply it as the name states, it is twelve thousand, two hundred sixty two or two hundred thirty ft deep. I remember I wrote a video about this. I did the video, and I did I did some math and found out I can't oh, man, now that i'm now that I'm sitting here, I don't remember the number. But I calculated how long it would take you to

hit the bottom. If you could fall down this tiny narrow shaft, it would take you a long time, right, And uh, you know that is very deep, obviously, but it's not deep enough to even come close to breaching the crust and going into the upper mantle. It's the crust is, on average underneath the continents anyway, two kilometers thick or twenty five miles. This thing went twelve point

two kilometers down, so not even halfway. Now, if we were to dig a similar hole in the ocean floor, we might actually break through to the mantel, because the crust along the ocean floor is around eight kilometers thick on average. But then you'd have to get down to the ocean floor. Yeah, so you'd have to deal with that. But at any rate, we haven't even breached the crust to get to the mantle, so we haven't gotten close

to the core. Uh, to get back to the to Jude's question, we haven't gotten close enough so that we could tap into the core's energy directly. Okay, so the core is pretty much a no go, and I would guess even in the future, we're not going to get direct access to the core just because of like the the heat and pressure involved once you get even a tiny fraction of the way down there would kind of

make access ridiculous. Well, yeah, exactly. You know they I've heard that when the the Super Deep hole was being uh, when the borehole was being drilled, that by the time they ended the project, they described the the rocks as behaving more like plastic than rock. That it was. It was it was deforming with the drill bit, which was making it harder to actually drill. So uh. And also you got to the mantle that's two thousand nine kilometers thick.

That's before you hit the core. So we're talking peanuts here, Like we are nowhere close to the core yet. But One cool thing I think about this is that if if in fact we haven't drilled down and we haven't had any direct observation, how do we know that the mantle is the way it is or that the core is the way it is? And the answer is we look from other sources, for example, and indirect sources, so

meteorites for example. By looking at the composition of the material and meteorites, we start to draw conclusions about what our own planet is like. So, for example, we have seen a lot of meteorites that have rock in them and fewer that have iron in them, which starts to have us draw the conclusion that iron, at least in certain forms, is probably going to be at the core

of a plant. It's going to make up a smaller portion it's going to be at the center, and that rock is going to make up a lot much larger proportion of that. Right, we can also guess at the iron content of the Earth's core due to the way

that the magneto sphere is set up. That's also true, and we can we can observe volcanic eruptions and see the material that is spewed out because the volcanic volcanoes extend down the the the magma can extend down all the way down into the mantle, so that gives us when it starts spewing forth, a closer picture of what's inside underneath. There also studying seismic waves earthquakes by looking

at how they propagate. So let's say a seismic wave occurs in uh San Francisco, and you look on the other side of the world, and you detect how those those vibrations go through when they eventually passed through there. Because we're talking about super sensitive equipment looking at this, by measuring the amount of time and the direction that it came from and the frequency of the waves, we can learn more about the medium or media that its. Yeah,

it's pretty awesome. That's I keep thinking like, this is amazing that we've learned so much through indirect observation. So cool question. Yeah, definitely. The one more thing about this question is that despite the fact that we're not getting it from the core of the Earth, geothermal energy is totally real. That's a power source. It's a renewable, clean

power source. I've heard that. I think some people do have certain concerns about it because you the main version I know about is steam powered basically, like you're injecting water into hot places and then using the rising steam to power a turbine. There might be other ways of doing it, but I know they're I've read and some people being concerned like, oh, is this safe to do? Is it going to cause earthquakes or something? But as far as we know, it seems like it's a pretty

good power source. That's definitely the main way that we generate electricity, right, I mean, like, we've talked about a lot of different methods to generate electricity, and they almost always come down to I almost and boiled down to you come down to steam turning a turbine. That that pretty much is the way that we we generate electricity for the most part. And now Jude's second question was about celestial coordinates really, or typically it was about how

to ask for not to navigate their space. How do astronomers say where a star is located? And here's the thing, guys. The main way that astronomers describe the location of stars is based largely off a similar way that we describe where something is on the surface of the Earth. It's like looking at the sky as if it were an enormous sphere that completely encircled our globe. So it's like our hebe is inside an even bigger globe which has little pinpoints in it, and what people literally thought a

few thousand years. Yeah, and what's interesting is that that that that remains the basis the main way that astronomers end up giving coordinates two stars. Now, there are a couple of others that we could talk about besides the one I'm going to focus on, Like there's the galactic method of coordinates and super galactic method, which is looking at stars from the perspective of say our Sun or

the center of the Milky Way. But for the most part, in astronomical circles, both in the amateur and professional world, we're looking at celestial coordinates, which are much more Earth based. And that makes sense because that's where we're looking at them from. Yeah, well, I can see how this would actually matter in the future, like if we encounter an alien species and we're trying to communicate with them about where something is. All right, So if you're standing in

times Square, it's totally it's like right there. Yeah, it doesn't doesn't help. So on Earth we have the human defined imaginary lines of longitude and latitude. UH. That's part of our geographic coordinate system. So the vertical lines are longitude, the meridians, and then the horizontal lines the ones that

are in parallel with the equator, that's latitude. And your coordinates are determined by where you are in relation to those lines, and the values are represented in units of degrees, minutes, and seconds or and this is becoming more and more common with GPS devices UH decimal degrees. So the equator is at zero degrees latitude, and if you travel north or south UH, you increase that latitude the north latitude or south latitude from zero to ninety degrees, so north

poles ninety degrees north, south poles ninety degrees south. UH. The Greenwich meridian represents zero degrees longitude, and longitude extends a hundred degrees to the east and hundred hundred eighty degrees sorry hundred eighty degrees to the east and hundred eighty degrees to the west, So one eight east and one a U west are the same. It's the same line that's on the opposite side of the world from the Greenwich meridian. Do you happen to know what that

line is somewhere in the Pacific Ocean. You're correct on that. Do you know what specifically? It is? The International date line. That's why if you go to Australia from here you lose a day. It's like a day never existed, which one of our co workers just got to experience. Uh, he's in Australian Now, Hi, Josh, how you doing anyway? So why do we describe it in minutes and seconds with degrees? What's the deal with that? So along the equator, one hour of the rotation of the Earth is equivalent

to fifteen degrees of rotation. Now, if you look at a circle and you divide up the circle into fifteen, you know, increments of fifteen degrees, you get twenty four twenty four hours in a day, thus the fifteen degrees of rotation. So if you look at lines of longitude, you'll see that their fifteen degree increments normally between these um So one second of time is equal more or less to about a quarter of a mile of rotation

at the equator. Uh. And the degrees can be subdivided into minutes and seconds this way, sixty minutes to a degree three thousand six hundred seconds to a degree. And now we take that same system, the latitude and longitude, and we blow up that globe. So it's this celestial sphere that encompasses our planet, and we just create a celestial equator. We take, we take where our equator is on our Earth, extend that outward as if it just continues.

This imaginary line continues out into space, and now we have a larger imaginary line that's uh, that's linked to our equator. That's the celestial equator. But at that point we don't call it a latitude and longitude anymore. No, we do not, because I mean, you know, we need to make things confusing, right, So instead of lady, we have lines of declinetion. Uh, in lines of longity become right ascension. So uh, the zero for for longitude or

right ascension really is the first point of aries. So right ascension is described in hours, minutes, and seconds instead of degrees. Because the passing of stars was a means of measuring time back in the olden days, and it's stuck. So uh, if you use this equatorial coordinate system, you would refer to a star's position relative to the celestial equator.

That's the lines of declination and where it is relative to zero right ascension, which is the point on the celestial equator where the sun would cross the celestial equator during the vernal equinox. Is it simple enough for you yet? Alright, so Polaris would be at two hours thirty one minutes right ascension eighty nine degrees fifteen arcamnuts declination, which is you know, easiest pie. But what happens now, No, this is a fixed system because it's based up on this

imaginary equator. Right, that's that's going to be the same for anyone anywhere on Earth. I have to stress on Earth. Obviously, if you were on some other planet, then this system would totally not make any sense to you. But what if you, Joe, wanted to tell somebody where to find a particular celestial body, and you know, referring to the celestial equator is not really convenient because it's not like we have a bright line across the sky that says, hey,

here's the celestial equator. You would describe the altitude of the star, which is how many degrees above the horizon it is. By the way, a degree is essentially if you hold out your thumb the thickness. The width of your thumb is essentially one degree, and if you hold out your hand, I think that's like more like fifteen. It's kind of interesting. Yeah, so your degrees may vary, but but your arm is longer. So so the perspective makes it all work out. But if you have short

arms and thick thumb, you're in a pickle. You're you're a bad, bad astronomer. You have no business looking at the sky looked to your feet at any rate. How many degrees above the horizon is the altitude, and then you have to describe the asimuth of the star asimuth that's how many degrees along the horizon with respect to them to a compass direction. So you start from north north is zero degrees, and then you go clockwise, so east would be ninety degrees because that's a right angle.

From north south is one degrees, West is two d seventy degrees. And this method of describing as stars position is completely dependent upon the point of reference of the observer. Right, I wouldn't be able to say, oh, hey, my friend in Alaska, right, look at this star. It's right there, per five hands exactly. That wouldn't work. Now if you were to use the other method I mentioned before with

the celestial equator. First of all, you both have access to math and abilities that I don't know about because I can't figure this stuff out on my own. But that would work because that's a fixed system. But the the one that requires the the point of view of the observer obviously that would not work in that instance. You're exactly right. So um. Also, this means that this system is not terribly useful once you get significantly far

enough away from Earth. Now, most of our manned missions have been really close to Earth, I mean low Earth orbit. Even going out to the Moon is not that far in celestial terms. Yeah. Yeah, you're still in orbit of the Earth. Yeah, so uh we. The big problem is that if you're talking about interstellar travel, this system is not useful. For one thing, it has nothing to do with the distance of stars. This is just their relative position within the view of the night sky from Earth.

So two stars that look close together because they seem to be close together, and that that imaginary sphere could be incredibly far apart in distance. One could be deeper than another, right, so it would be much further away. It's so the constellations are very um, very deceptive in that sense. You know, the stars that appear to be close together might be very far away from one another. Um. Now, keeping that in mind, how do we help spacecraft that

go beyond this? Because we have had unmanned spacecraft that went beyond Earth orbit. And one of the tools we use is called the Deep Space Network or DSN. It's network of three powerful radio antenna their a position around the world in such a way that together they have total coverage of the sky. So those three points mean that we can send and receive messages from any angle

off the Earth. Sun never sets on the Deep Space Network, that's correct, Yes, and up during I believe the late nineteen Yeah, the sexually ended up becoming uh came into effect just before the Apollo missions, and in fact, it ended up making another navigation system that was originally going to be the primary navigation system aboard the Apollo, the secondary or backup system, because now they could do all

the calculations from Earth. Yeah. So obviously, if you're making calculations from Earth, it doesn't matter if it's an Earth centric thing, as long as it still applies to whatever body happens to be out there in space. And in fact, these radio antenna what they do is they send out a signal and then they wait to get a return

signal from the spacecraft. And based on the time it takes from the moment of transmission to the moment of receiving that that return signal, as well as the shift in frequencies, the the the eggheads who crunch the numbers can figure out how quickly that spacecraft is moving where it is, like to an incredible degree of precisions. So, like judask, it kind of is like GPS in space kind of, but only for spacecraft, right, It's only for something that can radio back to us that. Yeah, it's

like GPS for your car. Yeah, it doesn't apply to stars, but it applies to spacecraft. So it's something like the accuracy. We can figure out the velocity two point zero five meters per second, and we can figure out the location within three ms, so it's even more accurate than some

GPS devices. Are just pretty phenomenal when you think of a tiny, relatively tiny item in space that is passing possibly outside of the Solar System, because this is how we contact things like the voyager probes um so it's pretty cool. Uh. Now, if we ever reach a time when interstellar travel is common, we'll have to create something called star maps or star charts that are accurate representations of the relationships of various stars, how far away they

are in in in three dimensions, not just in two. Yeah. I can imagine it being very difficult because when you think about maps of the Earth's surface that we're used to, these are basically two dimensional. I mean, they might have topographical information on them, but they're they're two dimensional planes. We've never had to think about space in three dimensions before. It's all been like Star Trek where all the ships

to Yeah, yeah, exactly. And even in say like video games where you're supposed to navigate a galaxy I'm thinking of like, uh, in the mass effect games or something like that, you typically get like a top down view of the galaxy that's still a two dimensional map. You know, you're looking down on it and everything's arranged on the

same two dimensional x y axis plane. But if you were actually navigating, you'd have to be you'd be moving to like too and past and through your points of reference for where you were well, and not only that, but the place you're leaving from and the place you're going to are also in motion, right, They're not, They're not standing still. So you wouldn't just be planning where you're headed. You have to plan where is your destination going to be by the time you get to where

you need to go. So this is this is a grand scale of the kind of calculations astronauts have to make and ground control has to make when launching something to say Mars, where you know, we talked about how to get to Mars, it takes between like six and eight months to get there because you're not launching to where Mars is. You have to launch to where Mars is going to be. Same sort of thing here, but now on an interstellar level, which makes it even more complicated,

really really complex. And in fact, the references I was looking at said, you know, we just don't have the information yet to create something that would be good for

navigational purposes. A lot of this would be stuff that would have to be done in exploratory missions, where it would be kind of like the early explorers who had set off in ships across the ocean, not knowing where they were going or when they would get there, and then having to map every thing out similar in that respect, but on an even grander scale obviously, so pretty interesting.

And there's also something cool I wanted to mention, Lauren, you discovered this actually, I remember Joe was telling me

about astronauts using sextance on board spacecraft. Yeah. Sextance, of course being the if you're unaware of them, the old nautical tool where you it looks a little bit like a pro tractor, except you site along it and yeah, you have to take you take the horizon as a reference and another body like the sun as a reference, and you do some calculations to determine where in relation to the rest of the planet you happen to be.

The astronauts did the same thing. They had a tool that well, well, they didn't have a protractor looking thing. There was like a pair of telescopes that were connected to a very sophisticated at the time device. Uh there was in a exposition by the way, so they couldn't move it. You had to move the spacecraft to look at the star you wanted to look at um. And the reason they had it was to correct for drift, right.

They would plan their trajectory and they would check to make sure that they were still on the trajectory that they had planned. So what they would do is they would cite two different celestial bodies, or they would use the Earth's horizon or the Moon's horizon as one of the reference points, and then a star, and then they would make sure that it lined up properly. And if it lined up properly, they knew that they were on

the right trajectory. If it was out of alignment, they knew that they were drifting, and they had to do a course correction to get that fixed. And one of the descriptions I read of how the system ultimately worked was really cool. So they would pick a star. The'd say all right, we want star whatever, and they put that into the computer saying, this is the star we're going to use as our reference point. The spacecraft would

orient itself to turn toward that star. Then they would look through the sextant and the sexton has a little crosshairs on it, and it's star is not in the center of the crosshairs. They knew that they had drifted. They used controls on the sextant to move the cross hairs over the star, push a button that sends a command to the navigation system to do a course correction so that the thrusters then do the necessary thrusting to put them back on the correct course and correct for drift.

And I read this and I thought that's amazing. Yeah, yeah, And and this was actually in use in several of the Apollo missions. I think, I think as late as Apollo eight they had a big mission. That's the one that went around the back side of the dark Dark Side, which is really really quite bright the far the far side of the movie. But yes, yeah, and and I think that the astronaut who specifically was using it was it was an ex naval officer. That's kind of appropriate.

Probably had his little Bosn's whistle there too, and everything. But obviously you're if you're talking about spacecraft that goes outside the view of the Earth, then you want to have this backup system clearly, because you aren't certain yet. You can't be absolutely sure that the Earth based navigational systems will stay in constant contact because once you get behind the Moon, that's a pretty big obstacle to block

your radio communication. So it is clear why they needed to have a secondary navigational tool aboard to make sure they could correct for things like drift. Okay, well, those are the only three questions we have time for in this episode, but rest assured we will be getting back to more of your questions and suggestions in a subsequent listener mail round up episode. Yeah, this has been so much fun. Yeah, but one last message I wanted to end with, just because it's very brief and we can

squeeze it in. It was some wonderful feedback on our Back to the Future episodes, and this came from Stephen on email. He said, I think you missed one important detail in your two Back to the Future podcast, the reason why we don't have all the new technologies. I'm sure he was talking about the things we were all disappointed not to have yet, like hoverboards and telescoping baseball bats. He says, the reason we don't have those things is

that lawyers were never outlawed. That is why Marty's kids were convicted so quickly. Than Yeah, thanks than Steve, I forgot that salient point Back to the Future book too. Lawyers have been outlawed, and therefore the the court systems moved much more quickly. But wait a minute, what does that have to do with the technologies. Well, I feel like I'm faintly grasping Steven's point, but I'm not quite saying. Is that because this one element of the future has

not come true, the other elements can't come true. And also without lawyers everything would move more quickly. Yeah, first of all, you wouldn't sorry lawyers, it's just true. Oh well, you know, we did just talk about intellectual property and the chilling effect of patent law and stuff. That's so yeah, any you this was This was so much fun. Thank you guys so much. We're very much looking forward to

doing this again. We do have other questions, some of which we have already started to research and talk about offline, So keep those coming in because we're having a great time. Some of these are going to be full episodes. Some are going to be like this one, where we collect some of the various questions that don't quite make up a full episode. And uh, it's it's fantastic and lets us know what you guys are interested in and we're

so excited to cover that. In order to let us know what you would like us to talk about, you should send us an email that addresses f w thinking at how stuff works dot Com, or drop us a line on Twitter, Google Plus, or Facebook. At Twitter and Google Plus, we are f W thinking over on Facebook. Just search f W thinking will pop right up, Leave us a message, tell us what you think, and we'll

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