 Morning EMF nice to be back back in the field again So the title of talk pretty much says it all we're gonna cover time zones in daylight saving time We cover a couple of other things first railway time, which is basically leads up to time zones And we're gonna solve the problem at the end of why your phone knows that it's daylight saving time even if you don't so We'll kick off in Britain At the tail end of the sort of industrial revolution, there's kind of two important networks that come out That affect timekeeping so the first is the rail network in about the 1830s and then the electric telegraph in the 1840s Okay, the usb is Okay, I'll rewind so you can now see what it talks about yeah times under the electric saving time So yeah, like I said at the beginning there's we're going to cover railway time because it's kind of leads up into the time zone system So it's probably worth covering that first and then the end we'll we'll answer the question of the phone and how your phone knows And when it's DST and not so railway time two important networks coming out of the late industrial revolution Rail network and the telegraph and they both have an impact on The history of timekeeping. This is the first intercity railway. This is the Liverpool to Manchester railway in 1830 going at an ungodly speed of 30 miles an hour Within about 20 years The network grows we get Top speeds of 78 miles an hour and in quite, you know, broad network pretty much everywhere is connected And there's some standardization that comes around around timekeeping. So to kind of explain To kind of explain Why the timekeeping issue arises is we're going to take an imaginary journey So let's say you get on in London London Paddington You get your stovepipe hat on in your copy of the Times under your arm And you're traveling to Bristol Temple of Meads. You're going westwards and it's going to be about a four-hour journey You've got incredible sight lines. You can see Ben Big Ben somehow from Paddington And you check and it's one o'clock in London. It's one o'clock on your pocket watch. You travel for four hours On your pocket watch, it's five o'clock But when you arrive in Bristol The clocks all say something different. They say four forty nine. See somehow you've gained 11 minutes Why why is that? So the to answer that question you sort of have to realize that at this point in time, there is no sort of time standardization really So in London, it's like here in Greenwich Park in London And you you see the sun in the sky and you track as it goes overhead and at the highest point in the sky That is noon in London You do the same in Bristol. So when it goes overhead that's noon in Bristol Those are not simultaneous events They happen about 11 minutes apart because the earth is rotating so Local time in Bristol is not the same as local time in London. They are off by a little bit So that's a problem if you're trying to make Railroad scheduling or railroad timetables So a bit of a trauma warning for this Next slide if you work in graphic design or user experience you might want to look way now This is railway timetables in the 1840s And obviously timetables are hard anyway, but when you get everything running on local time, it's just way more complicated So what came about was a sort of standardization or a move towards a standard time And GMT was the obvious one. I mean Greenwich Observatory had been around a couple of hundred years at this point and all of the Maps and you know some c-charts and whatever were all using GMT So it made sense to move on to GMT. So Great Western were the first to do it And it sort of became standardized in 1847 and then it took a while for it to sort of roll out to the rest of the UK But yeah by 1855 pretty much all the towns and cities had moved across And it wasn't universally Nobody's universally happy but obviously London was because you know you have to change your clocks or anything But bristol was the one was one of the ones that wasn't entirely happy about it This is the bristol exchange clock installed in 1822 The hands on the On the left hand side, there's two two red hands Those show the hour in the minute in bristol local time But that extra hand on the other side was added later And that actually shows GMT. So that's not actually a second hand. That's another minute hand so you can imagine sort of Bristol here then locked 11 minutes apart as it kind of moved around like that So that that clock still there I checked on street view before I came in so you can still go and see I I want to go see it But yeah, even bristol came on board eventually in 1852 so so imagine The same problem railroad scheduling timetables and so on In america a much bigger area. So you've got a much sort of larger More developed railroad network as well Um in 1853 shortly after britain's standardized on GMT There was a particularly nasty railroad accident on the providence of Worcester line railroad Many people died and it was basically attributed to bad scheduling So this is the railway network a little bit further on the 1870s and you can see it stretches all the way across the usa so that's quite um quite a lot of work to be done if you Want to take a journey from new york across to san francisco looking at that You're probably gonna have to jump a few few lines and the way that the networks were in america was all of the train Railroad timetables ran on whatever the corporate headquarters was for the railroad So new york central railroad ran new york time So if you're trying to make a connection you imagine you're sitting in somewhere in the middle And you've got to work at what local time is in york and then convert that in your head And then you've got a connection to make so you've got to connect to something else And there's all sorts of things done to try and make this easy, but it's it's not an easy problem to solve So standardization was one way to try and simplify this problem um america's bigger, you know So a time zone system was the sort of the way that they approached it looked at the GMT and then essentially applied it into five zones across the u.s notice they Sort of those the circles at the top that's degrees of longitude. So I don't know if we've got anybody any small children in them I'm going to kind of cover latitude and longitude very quickly so they wouldn't sort of knows what it is It's a way of pinpointing a point on the globe um latitude lines go around the globe um Big fat one in the middle much like myself Is the equator and then you've lines of longitude around pole to pole And we'd find one of those as being the prime meridian so that that becomes zero and everything else gets a number every 15 degrees around the earth um Having a prime meridian gives you a weird side effect called the international dateline which we'll look at in a bit as well so Right, so this is the time zone system and get the spiders out the way 1883 we've got britain on GMT You've got america with its sort of five zone system also using Greenwich as the prime meridian because of the way that came about um 1884 rolls around and the idea is to take this system and roll it out to the entire world So there is a conference to do that The international meridian conference meets in washington dc Yeah There's some fabulous moustaches and beards going on in this work Um 41 delegates from 26 countries including such stars of the optimum empire Um And hawaii which was actually an independent nation at that point. So So here's what they debated Um, there's lots of things on here Resolution two was the principal one. That's the one that says we are going to make granite or GMT the prime meridian of the world Um, here's what went down 22 nations voted for it Uh The dominican public vote against it. I've actually got I haven't got the bottom of why that was I would like to know Brazil and france abstained So by granite These were all possible meridians in 1884 um, every sort of major power in europe had an observatory and every observatory Made observations and therefore they had a meridian of their own, you know, france would have had the Paris observatory Uh, you know copenhagen for denmark, etc. So so all of these were possible. So why particularly granite? um Well, it ended up it's kind of boring answer really but it's pragmatism The us and british systems were already Using it. Um, so no there's no need to make any changes But the kind of killer blow really was that britain was kind of at the height of its Sea power at this point. Um, and british naval charts had granite on them So you didn't have to print a whole bunch of new charts. You basically just kept the old ones and granite was accepted so Right, we did a couple of things about the primary and if you get a chance I really do recommend going to the royal grinch observatory. It's in grinch park. It's beautiful It's got lots of fun stuff going on inside. It's got um, harrison c clocks and h4 and things like that. So um, but if you Go there you will probably get your photograph taken on this line because it's one of the things that you can do there That there is a sort of group of people. Hopefully you can see it in the photograph So the group of people on there and the crowd is on the line and you get a photograph and that's you on the on the primary It's worth pointing out the primary dean is a magical invisible line and it goes through all sorts of places So you could probably get your photograph much quicker in a pizza hut in mali or something, you know, there's There's plenty of places on that line, but the people everyone likes to go and get it done out there So i've kind of drawn the line on so it's a little bit clearer So the line in red is that's the line As it sort of runs in and you'll see it kind of goes in through a door and then it's dotted it all the way through Um This is what the back looks like my beautiful assistant here is demonstrating It goes into a door and you can see there's lots of flaps and stuff a bit further up and at the back You've got the same sort of thing. So the reason for that is the inside It all opens up And you have what's called the eerie transit instrument in there, which is essentially a telescope That's on a sort of cog if you like sorry, it only moves in one direction, but um, what it does it tracks Uh star in the sky and as it transits across The the sky so that's uh, that particular instrument was designed by george biddle airy who was the historical royal at the time um, and because the Prime meridian was defined as being granite this was uh, it was essentially the airy meridian specifically his meridian Um that became the prime meridian Fun fact, it's not his only one. There's one on mars um It runs through the airy crater as you can see it just there on the right hand side. Um, so yeah, he has two prime meridians which mad skills Okay, if you walk around granite you'll notice plaques on the wall So there are other meridians. This is the point of making the airy was the specifically the primary and um, john flamsteed who was the original first astronomer royal um, he gets one as well When they built the royal granite's observatory, it was um, they spent a lot of money on it But they didn't actually spend any money on equipment. He had to buy his own So when he got his act together and got some kit then he put it in that point and that became his meridian and the second one is the uh, Edmund Halley the second astronomer royal so you'll see these kind of dotted around if you're up there The other fun fact as well, I mean, I probably this crowd might know this one, but the primary and Is not the same as the gps meridian. It's official name is the international earth rotation and reference service meridian reference meridian But let's go and collect gps for now, but they're quite different quite far apart There's a bin that marks it so you can't actually find it if you if you're looking for it But it's not really or you can take your gps receiver and then you will find it. Um, the reason for this Is a little complicated, but essentially models of the earth in 1800 models of the earth in 1960s whenever Gps was being developed or have improved. So that's the short answer There is a paper on it if you're interested and you go into the all the details um The royal grants observatories not the only royal observatory in london I only found this out a few years back, but there's an observatory in q called the king's observatory built for george the third It's beautiful building looks really good. It's in a golf course apparently But um, I would like to get there at some point and of course it had its own equipment So it gets meridian so a few meridians in london, right? We're going to cover time zones in theory I'll do practice in a second, but this is how it's supposed to work Here's the earth we divide it 15 degrees of longitude um with a primary in in granite Um, which gives you an international deadline in the pacific Okay, how this works in practice is any territory that is in one in in a zone can be in the zone Or it can decide to be somewhere else and that happens a lot So actually, you know, I'll give you the width of the zone So the zones are 15 degrees apart as well But the the line down the middle and it's seven and a half degrees either side So it's they span 15 degrees from the center of that point. So if I take the lines away, it's probably a little easier to see Right in practice gets a little messier Because you know, it's the real world and there's country boundaries and all sorts of stuff going on Um, not everything runs on one-hour time zones either. There's quite a lot of half-hour time zones, um, dr. About and in fact, there's a couple of what three 45 minute ones in the poll being the most um sort of well-known example Uh the time the the thing to kind of know about This is such a messy thing the international dateline Is a phenomenon caused by having the prime meridian. There is no standards for this at all It's just a side effect of having the prime meridian So there's a lot of leeway in terms of if let's say you're piling a ship across The dateline is entirely up to you really when you set your clocks and how you how you shift across Any lines that you see are guidance really so this way you get quite a lot of um difference when you sort of See how google have it and how you know other maps and draw it because there really is no standard for it at all and of course people some Islands have jumped across the dateline. So you've got this Notion of the the line islands in curabati, which are plus 14 hours Which means at any point in time you could have three days on the go at once You get a monday tuesday wed same moment in time having three essential local Values. Yeah super messy. It's probably like a whole talk on that but um Other things too. China really should be three time zones when you look at where it's covering but it all runs on Beijing time Um, and then tarte guy. This is the one I kind of wanted to get at the bottom of When I kind of pitched the talk I didn't know the answer to this So to me it seems obvious that if you're at the poles the whole system falls apart Right, you can run around and be in all the time zones. You can jump across and you know How does that work? How does it actually work practically in in Antarctica? So what you've got here is all of the Antarctic research stations Um, I think kind of dull answer when I got to the bottom of it is that they more or less follow Whatever their host country is, you know, so the the the british would follow uk time They would also observe daylight saving time even though they really don't need to in Antarctica Um But it keeps you on in sync with your host country. Uh, and sometimes they hold the sort of same Time as their whether being server more like a supply station or something like New Zealand Perhaps they might keep New Zealand time because that makes more sense. So just practicality is what they've gone with And this other thing turned up when I was digging through it which amused me as well like not only have you got, you know, six months of daylight and six months of nighttime and Keeping wacky clocks to whatever your host nation or the clocks don't actually work very well They seem to go a bit fast. So yeah, I can't imagine what there's probably a good thriller in that Like things going wrong and when things actually happen or something all right something sensible. Let's do daylight saving time I think the way to understand daylight saving time Actually, the way to come at it is to look at daylight patterns across the earth. Um, that's a kind of useful way And so we'll look at the extremes. We'll look at equator. So the equator you've pretty much got 12 hours of nighttime 12 hours of daytime. There's not really a lot of variation Um, so you could move it. I mean, you could apply dst and just, you know, move a thing by an hour But why would you, you know, it's it's probably inconvenient. Just move your clocks for no reason And the poles are more extreme Like I said before about Antarctica, you know, you've got 12 hours of daylight 12 hours of That's right. You have six months of of daylight six months of nighttime Or, you know, a month of twilight in between so you can move the clocks as much as you'd like But it's really not going to make any difference whatsoever. You get more of the same just by moving it. So um, so where you actually get daylight saving time is in these sort of Temporate bands, if you like so sort of Europe, um, or Australia, perhaps, you know Anywhere about this variation over the course of the course of the year And the purpose of it really is to try and extend the amount of natural light you are getting in the evening In the summer because obviously you don't get as much in the I'm talking about the northern hemisphere here But you know, let's say you live in Greenwich. You get up at six o'clock in the morning Um in the winter you can see from here that you're actually getting up in the dark Like we've all kind of experienced this and anything below that line is stuff you're sleeping through, right? So there's a lot of natural light there that you're going to sleep through in the summer So the point of that of daylight saving time is to kind of extend that by shifting the clocks So that's what it looks like when you shift the clocks everything moves up and you get an extra hour of daylight in the evening So that's the purpose of it um It's usually attributed to ben frankling But really not no, I mean he was he wrote a humorous essay in which he suggests He makes calculations for how much candle wax you could save in paris He suggests firing cannons to wake people up So he's kind of playing with the idea of Getting people early But there's no notion of putting clocks forward and back or anything like that yet This is the first serious proposal. George Hudson. He was from london. He moved to new zealand and he was a keen entomologist So he wanted some time to look for insects basically. Yeah, he wanted a couple more hours in the evening He pitched it to the wellington philosophical society They were actually quite receptive. They were quite keen, but in the end it didn't really happen So this was picked up in 1907 by William Willett He was a successful london builder and his The buildings and houses that he made were famous for their kind of use of natural daylight. So this was kind of on his mind Fun fact, he is also chris martins great great great granddad. I think as well But I don't know what you would do without information, but there you go Um, he produced this pamphlet called the waste of daylight Here's what he was suggesting It will be good why you might want to do it and essentially it was about energy You know, you can save a lot of energy if you don't have to run lighting in the evening Um, he got quite a lot of support. I mean he pushed this the entire life Winston Churchill gave speeches on his behalf saying, you know, the extolling the virtues of daylight saving time um But the first known example of it actually being employed Comes from canada. Uh, this is thunder bay in canada. Oh, it called thunder being out. It was for william back then um, and for william and another neighbouring town Adopted daylight saving time. So it's in the records there. There may well be others But that's the only one we know of at the moment. Um, the first country to use it is actually, um, germany in world war two Um, they were again, they were using it to try and save coal to save energy Um, and the allies jumped on board pretty soon afterwards. Um, a lot of europe adopted it as well. So Um during wartime Britain was on double summertime. So we were effectively on european time, you know, we kind of shifted If the europeans were in summertime, then we've jumped to and we were we're on the say which makes sense If you're trying to coordinate a war the last thing you want to be Trying to get an off by one error, you know in your in your clocks. So Um in 2016, I don't want to say celebrated marked. Shall we say the x of 100 years of daylight saving time? There's a good exhibition at the royal observatory Worth the visit if you at the time So i'm going to look quickly now at dst patterns throughout the world because one of the things is it's within territories Not everybody Not every part of the territory wants to something something like australia like in the north the observer but in the south they don't Canada in the uconn they they don't in suscature when they don't but other places do Um, my favorite is america america is really unusual. Hawaii doesn't um and bits of arizona don't so What you've got here is you can see the red parts the arizona Officially do not observe daylight saving time, but you'll notice there's a kind of patch there. I've got it in blue I'm hoping that comes up and you can see it That blue area is the navajo indian reservation and it stretches out into utah new mexico and utah new mexico Observed daylight saving times when the navajo indian reservation also observes it even though it's in arizona However, there's a little red spot in the middle there. That's the hopi indian reservation It being entirely within arizona. It does not observe daylight saving time Yeah So we have dst used this was weird like I pitched this in january february and then march comes around and usa votes to put daylight saving time permanent daylight saving time In 2023 well, it has passed the senate hasn't passed the house and so who knows they've also gone down this road before and reverted it in the 70s So, um, I don't know if it'll happen. We'll see europe's also kind of in the same boat europe voted in 2018 to stop observing dst britain being part of europe that time was also with this but There's just been a lot going on. They haven't had a chance to To do it. So both ua and uk observed it this year, but I suspect at some point in the future. They'll get around to Making that happen I can't really leave it without trying to cover the pros and cons. This is kind of a modern take on it Basically, it's good for the economy, you know with an extra hour at night people go to bars people go traveling Um It boosts the economy by by a decent number, which is the kind of main purpose for doing it Um colons really you're giving yourself jet lag. It's just horrible, you know You're putting yourself forward an hour and there's also some heart attacks and accidents That go up as a result of the shift from one to another so Okay to answer the question of computers somewhere. I'm sure you've all got a phone in your pocket or something like that so There's a decent chance you're running android or ios or this being amaf you wrote your own who knows But if it's anywhere, so unix or linux based There's a pretty good chance it has a copy of the timezone database within it Timezone database has many names. It's been around since the 80s 86 and get started so This is what it is. It is a database that contains this is from their feq So I can get it right contains code and data that represent the history of local Time for many representative locations around the globe thinking I skirt around the line who's there It's updated periodically to reflect all of the things. I've just talked about so utc offset. It's still at the same time blah blah blah um The most surprising thing if you've not come across it is it's it's an open source project Um, and it's run entirely by volunteers like emf like this. This is an entirely volunteer driven project But it's fundamental to the internet like, you know, if this thing wasn't there Um, you'd have to set your own phone be disastrous, right? Yeah Um, there was a talk earlier this year from paul egger who is the current maintainer And he goes into a lot of the history on this So if you're interested in the history specifically of this, I recommend that talk I will link to it and tweet it later on if you're if you're up for it Um, here's how the process works So there's a mailing list and if you're at all interested in time zones that you can join the mailing anyone can join the mailing list Um, here's an example of an email that came in in march and it's from the palestine Ministry of telecom and information technology saying he are the dst rules for palestine for this year Um, that gets turned into an entry in the database which looks a bit like this and this was turned around in like A week, you know, I was done very very fast Um, and then what happens is the upstream Um, you know, if you're on debbie and a boot or whatever, you know That they bring that version in and then it's rolled out to all the other operating systems. Here's kind of looks up close Um The rule at the bottom is human readable. You have to trust me I think most techies would read that but think about it is that gets compiled for all the various systems as well Um, the most interesting thing I think is all of the comments. There's some fantastic Sort of notes on the history of time zones and they like saving and all sorts of you know, politics behind it Um, it's on github. You can look it up. It's it's well worth a couple of hours your time um and to finish this is You've all seen this this this feels right to me about the time zone database. Um, there are some threats to it It was sued in 2011. Um, there was a some heated discussion on the on the mailing list last year Um, but it is fundamental to the internet and we cannot afford to lose it So I know I'd like to thank by thanking the maintainers of the tz database frankly because you know my phone works So with that I am out