Why Do Clocks Run Clockwise? | Neil deGrasse Tyson Explains...

foreign ER for you all right so I I go to sleep and I wake up and I say I gotta explain her I got I got another one so they haunt me and until I release them in this medium and then I sleep well at night okay awesome well let's let's make sure you get a good night's sleep tonight all right I'm releasing the explainer demons the exactly the course within me this is this is the Neil deGrasse Tyson we're going to call these um the Neo melatonin mom moments melatonin moments you gotta say it right so do you know why clocks reckon time clockwise yeah is it wait that's just the way they did it and then all of a sudden we just started calling it clockwise Okay the reason is simple and complicated at the same time on the equator uh the Sun Rises due east and sets Due West every day of the year and it is the only place on Earth where that happens all right and so the cut and the Sun Goes High overhead giving literal meaning to high noon and then as you hike North the ark the sun takes in the sky goes farther and farther south it's no longer goes directly overhead it's just that the ark going from east to west just just sits lower and lower in the sky okay until you hit the Arctic Circle where the sun is like it's practically horizontal to the Horizon as it goes all the way around but we're we're here in New York City where middle latitude so the sun's path through the sky is sort of in the meat in between somewhere okay that means uh it's basically almost always south of you mm-hmm just think about that if on the equator it's to your left and above your head and to the right as you walk North the sun's Ark dips behind you and behind you is south okay okay it's South so here's the point in the northern hemisphere if you were ever facing the sun you will never be facing north it is never North ever this and where does the moss grow on the tree on the north side of the tree right the Sun never hits that side of these objects in the northern hemisphere okay in the southern hemisphere it's the opposite and they would grow moss on their southern side okay because the sun would always then be north of where they are and it's fun when I visit the southern hemisphere I'm always just rethinking all this it's just a fun thing to reconstruct the geometry of Earth in space relative to the sun all right okay so civilization as we know it began in the northern hemisphere what was the one of the first time keeping devices people used uh Sundial sundial so a sundial has all the hours of the day on a flat surface and there's a thing sticking up that actually has an official word I would just call it a stick but the official word is gnomen with a genome g-n-o-m-o-n nomen no gloman Okay so the nomen when illuminated by the sun cast a shadow on these numbers and you calibrate this depending on what latitude you're in on Earth's surface you need a different Sundial if you're at a different latitude each sendile only works for one latitude okay okay all right so picture this okay I got my sundial and I got my gnomen and the Sun rises in the East okay and as the sun rises up the Norman cast a shadow on these hours that are carved into the brass plate right and we can ask what direction does the gnomen shadow move right yes sundial gnomen shadow moves clockwise there you go all right all the way until the sun is in the west and it casts to Shadow far over on the right hand side of the dial if you're facing facing south well and then night time comes and no men knows what time it is look I mean facing north in my example that's right so so sundials are completely useless at night like Spider-Man in the middle of a meadow now you should did you come up with that I'll run Spider-Man stop F you Spidey if you're gonna now make a a wrist some kind of physical clock that is inspired by this amazing time keeping device called a sundial then it makes sense that you would track time in the same direction like Sundial track to time exactly so our clocks are emulated sundials a mechanical sundials that is so cool correct all right so this is evidence that Civilization that invented sundials did it in the northern hemisphere right because if it was the southern hemisphere well clocks would be running backwards clocks would be going counterclock counterclockwise correct and have you seen the counterclockwise clock in my office let me go get it it's over there look mini Neil is holding it I'll be right back okay so this is a literal counterclockwise clock look at that and all right you can see it so what time is it now so it's uh it looks like it like 401 402 and running oh that is so creep creepy it's it's so great it's it's a perfectly normal clock yeah It's Perfectly Normal except it's it's if the southern hemisphere civilizations invented time this is what clocks on your wall would look like that's great that's really cool that is trippy yeah it's a little trippy just to wrap your head around this and there's nothing weird about it no it's just weird it's it's just so out so out of the ordinary that it that it trips you out right right wow look at that that's cool so that's that's why clocks we go clockwise and then uh we invented digital time keeping where where there's just numbers and I remembered when that came out because that's how old I am I say wow we don't have to think about what time it is by looking at hands on a clock yeah the digits just tell you and what I found is people started forgetting how to think of time geometrically okay so if it's 12 30 you would and it said it you would say it's 12 30. in the old days you say oh it's half past 12. right quarter till a quarter two quarters and halves are geometry of a circular dial right okay and so that's why we think 15 minutes is a quarter of an hour yes it's also that in digital time but you're not thinking that way right the way you think of a quarter of a pizza or a quarter of a circle so we've lost think the power to think about time geometrically I mean some people have retained it but by and large not but it also gives a false sense of precision when I say what time is it it's always 12 33 did I really care that it was 12 33 really was that what I was after I just wanted to know it's about 12 30. right so not if you're trying to catch a train no it's like okay fine but otherwise okay often when you want it when you ask someone the time you just want to know the approximate time but when it's handed to you digitally you end up reporting it digitally right and that's and it becomes unnecessary Precision in the moment that's the just a simple Point yeah yeah and you know I have an analog wristwatch and and of course you see even the digital watches today you can put it in analog mode right yes where you can see the hand which I like and so now I have a I have a digital watch that that you can change the face of I mean and I have several different watch faces on here and and most of them are analog but it's funny that you just said what you said about the digital precision I don't use them because when I look down I want to see numbers you want to see numbers okay I want to see numbers now it turns out today everyone does have the exact time as each other right and I tweeted a few months ago I said gone in the era of the smartphone right gone is the scene in heist movies where people Gather in a circle and say what all right let's synchronize our watches it watch this gentlemen and so anyone in modern times say why would you do that yeah exactly aren't they already synchronized with GPS so so that is such an Antiquated prehistoric moment in a heist movie that it's it's almost clean and I say Dan I am that old aren't I yeah well nowadays it'd be like all right let's synchronize our watches and they'd be like what's a watch synchronize your watches I don't know how to do that I don't wear a watch time is a construct but a little to the youngins out there that Garrett wrist watches would lose or gain a minute a day right the accurate ones was a minute a week a couple of minutes a month so you were guaranteed to not match the time of other people if you're about to commit a crime and that's why you have people say what time do you have yes what time do you have no what time is it what time is it what time do you have right and that way that's the time your own little world and your own little watch yeah be like oh my God it's 4 30 I'm late oh wait a minute I'll just go in the kitchen it's only 4 15 in there friend in college who kept her clock 20 minutes early and I say why do you do that oh so that way I'm never late don't you know that it's 20 minutes early exactly yeah but I still and okay I couldn't I'm too yeah analytic to embrace that I just let it go yeah I was not going to have a conversation about that it'd be something different if she had someone randomly each morning set it ahead yeah you set my clock ahead I won't know what time and you don't know how many minutes or whatever exactly it could be two minutes ahead it could be 10 minutes it could be 20 minutes exactly that's right but when you do it you know it's like hiding your own Easter eggs and one last thing in the old days when they made chronometers that they would send out to see if you built a very careful seaworthy chromometer and you sent it out and it lost a minute a day you would not take it back to the shop to fix it you had a formula correction for it and you would not mess with it so after three days it would be slow by three minutes and you'd correct for that and so that's how how you got a clock and took it with you the clock and the correction formula so you would always you would always be on on time and On Cue oh that's yeah that that's thank God for the phone [Music] that sounds like a nightmare or jet planes right so I I just wonder in a hundred years and say all those poor suckers and back in 2023 they only had GPS and they only had this and they only had that I think I lose sleep over wondering how primitive it is what's going on with us that when people 100 years hence will look back and be glad they're not alive back in these backwards times or they'll look back and realize God those guys were actually alive that ah they all had some semblance of civilization yeah is that true mommy daddy is that is that tell me more tell us about the before four times dad before we became pets for AI yeah man who knows children there was a time when humans controlled artificial intelligence yeah what stuff up Dad yeah no that was true we invented them all right all right we gotta call it quits there that's awesome all right Chuck always good to have you always a pleasure this has been another Star Talk explainer Neil deGrasse Tyson here keep looking up [Music]

Channel: StarTalk

Views: 351,953

Keywords: startalk, star talk, startalk radio, neil degrasse tyson, neil tyson, science, space, astrophysics, astronomy, podcast, space podcast, science podcast, astronomy podcast, niel degrasse tyson, physics, clocks, clockwise, sundial

Id: P5rBJ746F1g

Length: 15min 11sec (911 seconds)

Published: Tue May 23 2023