What do you think the world would be like if we didn't have GPS time today? What technologies that we take for granted would be impossible?

I'm 59 years old, and I love these explainer videos! My kids are always confused when I say "quarter till" or "10 to". Even now, when I read a digital time, I envision an analog clock in my head.

Having been born in Ecuador, I grew up knowing that when I didn't cast a shadow it was twelve o'clock on any day of the year, always. And also how easy it was to recognize any cardinal point by seeing where the sun was during the morning or afternoon. My beautiful Ecuador 💛💛💙❤️

"Like Spiderman in the middle of a field" WONDERFUL. I laughed at this. :)

It never ceases to amaze me the amount of knowledge Neil has in his head!

I love it when I can laugh and learn something cool at the same time. I'm very glad that we have people like Neil deGrasse Tyson as a science communicator.

I was taught that in grade school. It was fun to revisit. As soon as Neil asked why clocks move clockwise, I immediately thought of sundials thanks to my 3rd grade teacher.

I don't know if this is the normal format for this show, but these two definitely make a good team. Informative with a healthy mix of lighthearted humor. 👍

If anyone wonders about the term ‘gnomon’ in the sundial… it actually was one of the first astronomical and geometrical instruments devised.. the g is silent only in the English form of the word. it literally means ‘the one who knows’, so it makes things ‘known’ to us. :) thanks for all you do! Keep up the good work and knowledge! You are my treasure channel

Fun fact: In my language, we don't actually say "clockwise". It's "with the sun", and counter-clockwise would be "against the sun". This little detail is actually important, since because of this naming convention, I've always known why dials on a clock face turn in the direction they do.

I remember when I was a kid in the early sixties. You could call a number for the CORRECT time! A useful service.

Chuck is by far the greatest co-host ive ever seen

For me, this was the best Start Talk yet. Interesting, informative and deep laughter. Keep 'em coming.

The sunset direction changing every season was one of the things that absloutely blew my mind when I experienced it moving from Yemen to Canada. Time keeping back home was so easy, I would easily know what time (hour) it is just by looking at the sun/shadow during the day. But then, moving to Canada with swinging day/night hours throughout the year was so confusing to me and so weird to experience.. I would lose track of time and will have to keep setting alarms or look at my phone to know what time it is.. definitely an interesting life experience, lol.

I did not expect this video to be as interesting as it ended up being. Love your channel. Making even the most seemingly mundane topics fascinating.

Back in junior high school, (many many moons ago), we had a history teacher we referred to as "the great stuffer". He made learning fun! Thank You for making learning fun! You both never disappoint.

I was in college when digital watches started to dominate, and I remember my roommate commenting that we were witnessing the beginning of the end of "clockwise." About 15 years later, a young boy asked me what time it was. I looked at my digital watch, mentally converted the time to analog, and told him it was a quarter to 5. He looked confused, and asked me, "That's 4 what?" I told him it was 4:45, but he didn't trust me, and I overheard him repeat his question to the next person he encountered!

Dear Neil and Chuck, greetings from the Netherlands. Thank you ever so much for this episode. I tune in every week, but I found this one particularly special. It felt like a splendid lecture, suitable for all ages. The discussion about the Sun and Earth, the North and the South, was truly captivating. And let's not forget Chuck's jokes - they were absolutely brilliant. The image of a pointless Spiderman in the meadow left me in stitches! Perhaps the lack of practical application of geometry in our daily lives, and the scarcity of geometric thinking, is the very reason we encounter a growing number of flat-minded individuals across the globe these days.

Actually, you can be in the Northern hemisphere, and have the sun appear north of you. This can happen anywhere between the tropic of Cancer at 23.5 degrees N, and the equator. You have to get north of the tropic of Cancer to guarantee that the sun will always be south of you. Also, definitionally, whichever way we engineered clocks to rotate is the direction we would call clockwise so...

In the early days of clocks in the UK , their times were set roughly by the time of the midday sun. This would mean that it would be 12 noon in London and in Bristol to the west perhaps 15 minutes behind. It became standardised when the railways arrived and they needed a standard time to set their timetables

Thank you I never looked at this like this. Very easy to remember. These are important factors to remember when hiking or traveling on Earth. Thanks again Neil’s, enthusiasm the way he conveys information is easily burned into the memory better that any teacher I’ve ever had. The passion is tool for Neil to express his knowledge. Thank you Neil and thank you to the host of this show. Keep up the good work.

Always an informative pleasure to listen to you two talk about science..

I remember asking my dad as a child if the world was in colour before colour TV. I'm sure I'm not the only one

Neil, thank you for doing what you do. I love that you have the knowledge to explain things to rest of us in a way we understand. Learning with you is a pleasure. Thank you! 🙏🏻

Always fun to listen to what Neil's got for us. Thanks friend 😊

Worst part of losing analog clock face is that I have actually had to explain to a twenty-something that "a quarter past 1" was 1:15, not 1:25.

I lived in South Africa and after I moved there, getting accustomed to the sun being in the North took a month or more. I learned the sundial movement of clocks in 4th grade. Thanks to my 4th grade teacher Mrs. Della Jo Rowan I became a science nerd!

“Unnecessary precision in the moment” is perhaps my favorite comment of the whole show; great show guys!

When I first read this title, I thought of sun dials as the precursor to the modern clock, and it blew me away when Neil started talking about a counterclockwise clock. It was then that I remembered that back in the 90's, I had a "Goofy" watch which was exactly that, a counterclockwise clock. I LOVED that watch and wore it for years! So much so, that I became very good at telling time by it. And of course, I would always show it off to my friends at work. But what eventually happened was that when I looked at a regular clock, I ALWAYS had to take a moment to figure out what time it was! When my goofy watch finally but the dust, I had to learn reading a regular clock for a second time in my life!

That's the first thing I noticed when I moved to the US, the sun was never in the middle of the sky. It was south, and the fact that the sun was always away from the center, my perception was that it was always either later than it actually was or earlier than it actually was. I was born in Colombia, and the perception of the sun changes a little bit due to the position of the country on Earth...

Lmao, Chuck and Niel are a perfect duo.

One of my favorite books: Name of the Wind, the author uses different phrases for "clockwise" and "counterclockwise," which he calls "against the sun", or "the unlucky way." Beautiful and quirky.

Excelente este video. Aprendí mucho de la historia del reloj. Gracias.

In two different _Columbo_ episodes (in the 1970s), a killer changed the time on their victim's watch, both in each case the victim was a Personal Assistant who'd always set their respective watches five or so minutes early, so the changed time on the watches was the killers' undoing...

An interesting fact left aside, is the seconds hand addition to the clocks, which happened along the Industrial Revolution. Without it there was no shared sense of the pace of time passing, how fast it does. But industral processes involved human resources to work in sync with machinery, and the seconds hand allowed humans to internalize a sense of the time pace and a sort of imposition to hurry up in our activities to keep up with it.

Once again, great content guys!!!.. I remember watching my dad wind his clock everyday.

Just saw this Video and thoroughly enjoyed it. I grew up with analog time pieces that you had to wind up every day and never new the answer.

Awesome as always! Thanks for sharing so much cool science with us guys love the show.

I had commented in a previous episode about this clock. I was asking why the poster and the flag look right, whereas the clock is reversed. Now I know! As far as the word "gnomon" goes, it comes from the Greek word "γνώμονας" which in geometry is commonly the triangular clear plastic instrument that often comes with an embedded ruler and proctactor.

I love how these two gentlemen have fun discussing these topics. 'At night, Gnoman knows what time it is...' too funny. The funny part about the precision of time is that there's an old joke that says that a person with one watch knows what time it is, the person with two watches is never sure what time it is. Because the watches would never precisely match.

I love Star Talk. I could listen to Neil and Chuck discussing these things all day long and never get tired of hearing their explanations. They make science fun.

One of the most amazing things to me about your discussion is that Neil said if southern hemisphere people had "invented" time. I sometimes think that time isn't real, that it's a construct we created or invented in order to orient ourselves in time and space, to manage being in these body-mind contraptions.

My backwards clock was red. Drove people nuts when they cane in my office and it took a while for them to figure out what was off. I hung it behind me, so someone entering saw it, but when I looked in the little mirror I stuck on my computer monitor, it looked correct to me.

There is an extraordinarily interesting book on this topic called Longitude which anyone even vaguely interested in the topic ought to check out from the library and read. It was truly Earth changing in a way that few things are. It is also worth reading Guns, Germs and Steel to understand why it was the northern hemisphere that made this decision as well as his follow up book in which he reconsiders some of his conclusions.

Until my retirement there was a analog wall clock in our house which I used to set 10 minutes faster. The time is set whenever we change the battery, usually once in a year. Though we know it is faster, it generally helped us to be on time. My father also used to praise me as a good practice 😊

I remember the setting mode on my old wrist watches that just reset the seconds to zero on a button press. Used to wonder what that was for until I understood what "synchronize our watches" meant. Then I used to wonder why nobody ever said *what time* they were synchronizing to or actually give a "mark" for the synchronization. They somehow, via movie magic, managed to synchronize watches to the correct time by just using the "synchronize our watches" incantation.

You both were on point with this one!!! Funny as well as educational 👍🏽👍🏽

Konark Sun Temple in Odisha, INDIA is another true example where in 13th-century CE (year 1250) they harnessed these concepts and many others around sun. The clock, the birth, adulthood, marriage, pregnancy, family, spirituality, crops, gods, art, stonework and what not. One of the fine example of civilization in those times. Also, there are many Sun temples of those times in India and many Sun dials around many cities of INDIA. A good place to visit and learn.

Thanks guys awesome conversation that I leant from today.

Many years ago, when I was in the Navy, I had a clock in my workshop that ran counterclockwise. To further confuse visitors to the shop, I had painted out the numbers and replaced them with dots. I could always tell the time, but loved to see the look on people's faces when I did so. (I also read backwards)

That was a better explanation than I thought it would be. Mechanical time pieces emulate the sundial. As for digital readouts, I prefer analogue along with digital because it allows me to visually see how much time I need to start getting ready in order to leave and be where I need to be on time. It is analogus to me converting kilometers to miles in order to know, experentially, what the distance, or speed, actually is.

At 3:08, I believe there is a correction. In the Southern Hemisphere, the moss grows on the northern side (not on the southern side as NDG mentions)

Thank you Neil and Chuck for making sciens so much fun for everyone!....

Damn. I always learn something new when I watch Neil's clips and this is no different.

7:45 that is pretty interesting. I know of sun dials and yet I have no experience with them or did any kind of testing to see how it would work in the Northern or Southern hemispheres. This was something I had yet to discover. Thank you Neil for sharing important information about my environment and the science around me. I think that this is one piece of the stepping stone to discovering that the object we stand on is round. And of course combining calculations of shadow distances of standing poles of the same height on the same day at the equator and in the northern and southern hemispheres to calculate the curvature (Learned from Carl Sagan’s Cosmos series). And then they needed someone to prove it by sailing across the large body of water. That is fascinating. Neil, you have blown my mind. Thank you again! 😅

Thank you for this informative and funny video. I enjoyed it a lot

Neil. You are in good company. Grace Hopper, of computer programming fame, also kept a counter-clockwise clock in her Navy office! As I recall she said she kept it so people would think about how things could work differently.

you two are such a good combo I love watching these so much

Thank you for covering this topic! It was keeping me awake every night! I can now finally sleep in peace.

I absolutely love these explainer videos. Amd this channel.

This is fascinating. Thank you so much.

Suprb explanation. Making science interesting and taking it to the masses in the language they can understand easily. Great work and we love your work, from India.

The most interesting part of this is when Neil talks about thinking in time. Reminds me of the film, "Arrival". After I started my own business I realized I stopped thinking in hours. I started thinking of work that needs to get done. What time it was no longer matters. How long something might take still mattered. Animals perceive time differently too. Hummingbirds, cats, insects, humans... all perceive the passage of time differently. It makes me wonder if research is being done on how understanding time can change productivity, happiness, etc. I remember in school we learned about the months of the year from 12 posters that were up on the four walls of the classroom. The teacher put the three spring months on the east wall, the three summer months on the south, the three fall on the east, the three winter on the north. That visual representation of the months is how I learned about the passage of time through the year. So when I think about the summer in my head, we're going into June which means the visual calendar is somewhere facing SouthEast and near the end of June it will be facing directly South. It took me about 30 years to suddenly realize, I don't think other people think about the year the same way I do. I think of it as this oval that follows the cardinal directions and other people think of it as a linear flip book from one month to the next. Strange.

As an Air Traffic Controller (ret.), we had several requirements to advise pilots of the current time. It seemed silly in the days of GPS navigation but it's still required. "Expect further clearance, 1945z. Time now 1920z"

I love Neil, but the channel would not be the same without Chuck. Perfect duo! Great job guys.

We had one clock in our kitchen that always was 30 min ahead of actual time. This was so my dad would leave for work on time. Even though he was the one who set that one clock ahead! He said it was the only clock he could see when drinking his coffee. He did have a watch with the correct time though. It was years after he passed that my mom finally changed it to the time.

Great info and conversation. I used to set clocks in my house 10 minutes early. Amazingly it did help me be on time.

Glad you found the "time" to explain that!😂❤

If you want to talk about weird clocks, I made one with a single hand where the numbers rotate instead of the hands. It gives a different geometric perspective on time.

Wow, Neil, how did you even become determined to learn *why* clocks run clockwise? I always considered it to have merely been a random decision that we all accepted. So... thanks for the education! I just love StarTalk. Of course, now I want an analog clock that runs counter-clockwise, just for the novelty of it. 😁❤️

Hey don't feel bad, i recall getting our first dial phone.. about 1953. Att gave us a short swizzle stick to dial it. Many older folks were afraid that they would cut fingers. As morse code learner later i was agile enough with my fingers to dial with the hang up button switch. I later read " notes on the network" as a radio systems engineer. There are still fossil like features of the telco that go way back. As Boy Scout, later as Army Signal Corps officer i learned to tell time by circum polar stars. Am hobby level astronomy buff and enjoy your programs greatly. And the humor. Karl

You guys are great . Keep it up !

chuck is on fire, love it

Haven't watched yet. Is the motion inherited from the sun dial?

This was an excellent discussion. I learned a lot and laughed a bunch.... Great work guys!

Now, @NeildeGrasseTyson needs to do an explainer on how we keep time in the modern computer era with NTP, or the Network Time Protocol. I can’t wait to hear Chuck’s take on the Stratums!

Barber Shops had clocks that ran Counter Clockwise with reverse numbers on the face. This is so that when they looked in the mirror they could know what time it was as they cut their customers hair.

Always interesting, thanks.

12:05 I currently have my clock set to 8 mins ahead of Standard time, yes in the back of my mind I always remember that. But I keep it ahead to leave because the bus sometimes goes early. It's a sweet spot running on your own standard time zone😂

Could you do a video explaining how a person could tell the time of day if they didn't have a watch or phone?

As someone from the southern hemisphere, I want Neil's clock.

Love the banter between you two. I had to look it up, but you two have been friends for almost fifteen years! I had one question: what about the fact that the sun's apparent position changes from approximately 23 degrees south to 23 north throughout the year? Doesn't this change the angle at which it would strike the gnomon (thanks for teaching me that word, BTW) alter how a sundial would read the time?

lmaoo this is a great episode love Neil's point about the time sync scene in movies

I worked for a government lab in Salt Lake City, Utah so everything was run on a 24 hundred time so when I retired I continued using 24:00 as my time. Then I moved overseas and discovered that most of the world uses 24:00 time system. I now live in Thailand and everything uses the 24 hour system so I am right at home.

A bit of additional trivia on the topic of the workings of a sundial. You will only ever see rainbows towards the West in the mornings or towards the East in the afternoons and never towards the North or the South. From where you stand you will always be smack in the middle between the sun and the rainbow. As you view a rainbow, the sun will always be behind you. So, technically you can use a rainbow as a compass of sorts 🙂

What a fun presentation. Brilliant

I'm 70 and grew up with analog clocks. I luv digital now, and time needs to be more precise these days. But I still think in analog and sometimes "translate" from digital to analog in my mind.

Very interesting as always! If you lived right on the equator (or within plus or minus 23.4 degrees of the equator), wouldn't the arc the sun travels switch from south to north (or vice versa) depending on the season? I realize that not a lot of people live in that zone, but wouldn't those ancient Mayans must have been horribly confused?

I keep my clocks at home 10 mins fast. It works and it's really a thing.

Here's an interesting fact: I am in love with this UKposts ?show? I have never had nor do I openly show an interest in these topics but damnit Neil, you make this so much fun to learn about! I'm feelin' interested thanks to feelin' this.

I used to set my watch early. You still forget as you look at so many other time keepers during the day that you tend to forget sometimes especially when looking in shock what time it is which boost your rush mode and then only realize a bit later that you are still on time

I still set digital clocks ahead😂 over time you forget about it and Live an hour’s drive away from anything so the bit extra makes me happy when I see the bank clock, because I set the cars clock ahead too. Lol

The British Army (and i imagine others) synchronise watches at the end of a briefing before an attack. Not everyone has GPS controlled watches. Without the synchronisation the attack would start before everyone was in place.

@StarTalk Dr. Tyson's laugh is contagious, looks like it is coming form the core. Love it! 😄

I have learned a lot from you, Thank you!

Time is fascinating. I worked the subway stations for nearly 10 years. From one end of the city to the other. Every so often I would notice the city would be saying that, "Today just flew by" or "The day was just dragging along." How can an entire city, with no interaction with each other until they used the subway, complain about the same time paradox unless it was effected by it? Maybe a time distorted bubble the earth passes through in its revolution around the sun. Maybe random waves of time distortion hitting the earth? Maybe they're randomly given off by the sun. Maybe they're from outside our Terran system and reach us in intervals. ???? Ti-i-i-ime, is on my side. Yes, it is

Sundials should be a reasonable source of how the mark moves around a dial. Also, it fits well with how the modern, western writing goes from right to left. I sort of thought this before the video had started. Anyway, it has never weighed on my mind, I just took it as a matter of course. Thanks again to Chuck for providing more humor, as well as Neill for dramatizing the events leading up to how we have ended up with the clockwise movement.

Where I worked in the 80s we had an engineer called Guy. He was approaching retirement then, but he had a watch that lost about 2 minutes an hour. He never changed it but if you asked him the time he would always get it right. A true British eccentric.

When I was younger, in the 1970's, our local barkeeper had a clock just like Neil's that hung on a post in the middle of the bar. If you're sober it makes sense when you look at it you can know it's running anti-clockwise. If you're sitting at the bar, half in the bag, you could look in the mirror behind the bar and know the correct time by looking at the hands on that clock.

Two small corrections: 1 - sun DOES go north of equator, up to the Tropic of Cancer, so you technically have a lot of oportunities to watch sun slightlyx north of you while being north from the Equator itself. Though this is valid only in the summer and the closer to tropic you are, the rarest such days are. 2 - being time invented on southern hemisphere, the clocks would still go clockwise and not counterclockwise; just the meaning of clockwise and counter-clockwise would be opposite of how we perceive them currently ;)