Neil deGrasse Tyson Explains The International Date Line

What is the International Date Line? Neil deGrasse Tyson and comedian Chuck Nice break down the history and purpose of the IDL. How do we know we needed a date line? Find out how the need for an international date line was discovered and why it was an accident. Where did we decide to put the date line? Plus, Chuck questions the existence of Mountain Time.
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Science meets pop culture on StarTalk! Astrophysicist & Hayden Planetarium director Neil deGrasse Tyson, his comic co-hosts, guest celebrities & scientists discuss astronomy, physics, and everything else about life in the universe. Keep Looking Up!
#StarTalk #neildegrassetyson
00:00 - The international date line is weird
02:00 - Circumnavigation & Time
08:07 - Observer Bias
11:40 - IDL Placement

[@StarTalk]

Which time zone are you in?

[@j2323j]

It’s 12 right now

[@CountGremlin]

Eastern time zone, the correct one 😂

[@BrianPhillipsSKS]

EDT/GMT -4

[@raleindecker]

Alaska 🥳

[@toon3ry]

GMT baby!…I’m on my way home on a train and my sides hurt cos I’m grunting trying to hold the laugh in so people don’t think I’m crazy…very informative and entertaining episode😂

[@celsopinheiro]

The passenger steamer SS Warrimoo was quietly knifing its way through the waters of the mid-Pacific on its way from Vancouver to Australia. The navigator had just finished working out a star fix and brought Captain John DS. Phillips, the result. The Warrimoo’s position was LAT 0º 31’ N and LONG 179 30’ W. The date was 31 December 1899. “Know what this means?” First Mate Payton broke in, “We’re only a few miles from the intersection of the Equator and the International Date Line”. Captain Phillips was prankish enough to take full advantage of the opportunity for achieving the navigational freak of a lifetime. He called his navigators to the bridge to check & double check the ship’s position. He changed course slightly so as to bear directly on his mark. Then he adjusted the engine speed. The calm weather & clear night worked in his favor. At mid-night the SS Warrimoo lay on the Equator at exactly the point where it crossed the International Date Line. The consequences of this bizarre position were many: The bow of the ship was in the Southern Hemisphere & in the middle of summer. The stern was in the Northern Hemisphere & in the middle of winter. The date in the aft part of the ship was December 31, 1899. The date in the forward part of the ship was January 1, 1900. The ship was therefore concurrently in: two different days, two different months, two different years, two different seasons and in two different centuries. Euller, John (Sept.1953). "A freak of navigation". Ships and the Sea. 3. p. 18

[@handmadehearts]

That is simultaneously brilliant & astonishing. Thanks for sharing.

[@abeb2300]

Did anyone do this for Y2K's eve?

[@jeffs6090]

That's a pretty sweet story. Kind of like being on the four corners in the US. However, I wouldn't say it was in two different centuries since the new century starts in '01 since there wasn't a year zero.

[@TheBeavadelic]

Haven't heard this story for years! Thanks for sharing 😁🤟

[@RickBlaine1941]

Same century. There was no year zero so the first century (i.e. 100 years) is from 1 to 100. The last year of all A.D. centuries is of the form digit+0+0. For example: 1900.

[@BSaunders87]

Chuck is freaking hilarious. Adds just the right amount of levity to what is already a really interesting piece of science. Thanks both!

[@lemongavine]

He was cracking Neil up more than usual. So funny.

[@Real-Eric-Cartman]

I'm always disappointed immediately if I start a video and the co-host is anyone but Chuck

[@ogelsmogel]

​@@Real-Eric-CartmanSame. Neil and Chuck together is unbeatable.

[@johnfrew2798]

Science show not a comedy show

[@johnfrew2798]

He trying to keep up with Neil being smart so he has to be funny which he is NOT

[@matikassantos8218]

I'm from the Philippines and I'd like to add that Ferdinand Magellan died in the Philippine islands when he was trying to convert the native Filipinos to Christianity and got involved in the rivalry between two tribal kings. Magellan tried to convert one of those tribal chiefs by force. He had around 60 troops while the resisting natives numbered 1,500 in the Battle of Mactan.

[@SpottedPop]

Those damn missionaries

[@ElijahPaulEugenio]

Yes, and not just been killed without any reasons.

[@THEC.O.VISIT.]

Christianity, or Catholicism? Big difference.

[@nyendwa]

@@THEC.O.VISIT. Catholics invented Christianity

[@exoticmarrow1346]

catholics are by definition christian

[@gabecrigger2204]

You guys have shown me how much I truly love science. You have taught me so much in the recent years. I have decided to quit my factory job and go back to college to pursue a science degree. Thanks for all you do, and inspiring me to pursue something I love!

[@J040PL7]

If only teachers were all like this, then we'd have a lot more promising minds working on our future

[@dmd7472]

Thanks for writing this 🙏

[@StarTalk]

We're heartened by this comment, Gabe! Best of luck to you in your pursuits!

[@JohnCater5]

If you want to understand the IDL, don’t watch this. The thumbnail is wrong. And at about 5:00 minutes, they get the Tuesday/Wednesday thing the wrong way round.

[@jamescpotter]

When I was a young kid my father told me a story about the international dateline. Dad served in the 13th Army Air Corp in the South Pacific. In one of his many bombing missions (he was a tail gunner in a B-24 Liberator), the squadron took off late on a Tuesday night, bombed their target on Thursday, and returned to base on Wednesday.

[@AmbrishSaxena12]

Neil is one of the real messenger of the universe.

[@savagepro9060]

he's atheist, so it makes you wonder WHICH universe

[@BassNinja]

I disagree Anton is

[@larryselkirk426]

@@savagepro9060 : The real Universe.

[@c4element1]

We all float down here

[@strikerbowls791]

​@@savagepro9060 🤡

[@wahn10]

I appreciate Chuck so much in these episodes. In addition to his quick wit I love his intellectual curiosity, which brings out the joy in Dr. Tyson, who is an incredible science educator. Chuck sets a great example for laypeople like me who are interested in science and willing to learn many new things.

[@kenrothstein8021]

He's an unfunny clown who slows this entire episode down.

[@Silvia6]

Once again an interesting topic explained in an entertaining and informative way. Thanks very much.

[@StarTalk]

Thank you for the kind words!

[@boryslebeda6908]

Well there are at least few mistakes: 1. Fernando Magellan spelled without D at the end 2. He didn't make it: dead somewhere near Indonesia. 3. They traveled westwards, not as it shown in the video 4. They actually should have gained a day and thought it was Monday instead of Tuesday, not Wednesday

[@TheDibule]

My thoughts exactly. Too bad they made those mistakes. They specified that Magellan himself didn’t finish the trip.

[@CoreySMX]

I only caught number 4. Literally paused the video when he said they lost a day and came to the comments to see who else caught this

[@blue9multimediagroup]

Magellan's first name was Ferdinand. Not sure where you got that from.

[@TheDibule]

@@blue9multimediagroupMaybe from Magellan’s name? 😅 His name was Fernão de Magalhães in Portuguese, translated to Fernando de Magallanes in Spanish. Fernand de Magellan in French. I guess English speakers use Ferdinand because « Fernand » isn’t a name they’re used to, but it’s certainly closer to his original name. 😊

[@RelakS__]

This drove me crazy in the last couple of minutes. If you go west fast enough (as fast as the Earth rotate in your current location), you will have eternal noon, while other peoples live they daytime/nighttime life without problem. But if you go to east the same speed, you will have 12 hours days, so you live two days during one day. If I understand correctly.

[@curtissschneider39]

I think Neil has it backwards. If you travel west chasing the sun, you'll experience one less day as you will have revolved around the earth's axis one less time than everyone else. That's why you have to add 24 hours when you travel west across the international date line.

[@MichaelWehrley]

I think you are correct. Additionally, I think Magellan went West and Antonio Pigafetta would have thought it was Tuesday when he got back and everyone would have told him it was Wednesday.

[@OnLee_Quality]

There is a logical error Neil made: Magellan’s scolar would have believed he was in the past compared to the people who stayed home. So he would’ve thought it was Tuesday while the people said it was already Wednesday.

[@cybore213]

Exactly!

[@kimutaiboit8516]

I was confused too. I remember reading a work out of fiction where a guy made a wager with people back at home that he could go round the world in 80 days. He kept readjusting his timepiece but his servant didn't. Getting back home he thought he had lost the wager by a day only for his servant to tell him they were right in time. Guy walked to the pub just before the clock chimed the exact hour.

[@pragmaticcrystal]

Thank you for your time and effort you are much appreciated 💛

[@StarTalk]

Thank YOU for watching :)

[@mannym7849]

Honestly you guys are the best! Thank you both so much for your highly entertaining explainers and the humour you both inject into them makes learning so much more fun 😂😂😂. You are the perfect combo! Thank you, thank you, thank you!

[@pbible]

This is the most entertaining science channel ever. Neil and Chuck are quite funny, and you learn something in the process. Who could ask for more?!

[@fc-qr1cy]

this was a great episode plus more than likely factual humor..

[@Akroness1445]

Love you guys I learn so much from you two!!!

[@jaredmgrant1003]

I have to say as someone who grew up in mountain time. It was amazing. Could catch an east coast mlb game by running home early and could catch pst games and not be tired the next morning. In Central time now and miss the BEST sports timezone for American sports.

[@StarTalk]

Great point!

[@Orion225]

This is the subject I'm very interested in. Glad you brought that up.

[@h.z569]

Love me some explainers, favorite segment, especially with Chuck as the side kick

[@zenamon]

Cheers to The show !!! Espetáculo !! From Portugal

[@carlatteniese2]

This is the funniest I’ve ever seen Chuck! Good on you fellow humorist!

[@deanacousins]

Lol 😂 It's been a long time since I've genuinely smiled and laughed! I retain way more information while I'm being entertained. Thank you guys! ❤😊

[@debbiemanning3910]

You 2 guys are BRILLIANT together!!👏🏾As a Blerd & Comedian I appreciate y'all I learn & laugh I LOVE IT!😂👊🏾💪🏾🖤

[@travisstump3785]

These two are hilarious. I know that every time I click on a new video, it's going to be a good day.

[@k8tina]

I'm in the part of Florida that is in the Central Time Zone. My family on the East Coast are still confused because they continue to think all of Florida is in the Eastern Time Zone! Also, telemarketers mess this up too, not realizing that the Florida panhandle is in the Central Time Zone

[@waynegosson1793]

I loved this video. Thanks guys. Such a great story!

[@PhDuh42]

I live in the mountain timezone and I have online tutoring students all over the country and occasionally on other continents. The only appointment that I ever missed was with a student in Arizona because I didn't realize that while I was on MDT, they were still on MST. At least I haven't had any students in Newfoundland 😮

[@psmirage8584]

I'm proud to be a Mountain Timer. I'm looking at the map now, and I'm at just about the narrowest part of that time zone.

[@CountGremlin]

I remember that Zack & Cody Timezones episode. As a kid, i thought the international line was just a made up movie thing 😂

[@stein1385]

Startalk has on some of the best engaging science ever ❤

[@darcioehler2942]

Did Neil just say " see you next Tuesday"? And did you hear Chucks response..... omg love the two

[@cappyjones]

I left Seoul, stopped in LA for a quick layover, then flew to Atlanta and watched the sun set twice in the same trip 😁

[@davidecasarin4953]

Now think how many sunsets were watched on the same trip by Magellan

[@easwarsankar]

It is actually Yesterday to the East of the line, not Tomorrow

[@TheSilverShadow17]

The most straightforward analog is the US and Japan and how Japan is 15 hours ahead of America because of the International Date Line.

[@georgeince4136]

That was a fantastic video. I married Filipina, and for years, I knew that there was a twelve to thirteen hour difference and that they were a day ahead of us in New Jersey due to the international date line. And the earth revolves counter clock wise. You guys are great 👍.

[@Amalgamotion]

I love this subject and my favorite duo have made a great video, you guys are too funny. As a dual citizen I start celebrating my birthday early as a Kiwi and end it as an American

[@alger8181]

I was taught that Magellan was the first to do the around the world trip, when i was in grade school (for non-Americans, around 8-10 years old). And throughout the rest of my scholastic career, and if fact until this day, never did any teacher/instructor say that Magellan didn't actually do the thing he was reported to do. Thank you again, American school system. Mythology is ever so much better that fact.

[@EM-qx3hx]

Here’s the truth: Ferdinand Magellan was Portuguese, he left Spain in 1519 with the intention to circumnavigate the globe, but died before completing the trip. It was completed by Juan Sebastian Elcano who arrived at Andalucía, Southern Spain, in 1522, three years later. It is a fascinating story, I recommend everyone to find out all about it. BTW, Elcano is the name of a beautiful frigate that is Spain’s Navy school.

[@alger8181]

@@EM-qx3hx Thank you.

[@TomLeg]

Worth thinking about the pre-eminence of European countries. The Date Line is totally arbitrary, but European countries decided to set it somewhere far away. If you live in the Pacific, you would place the dateline running through London.

[@Ptaaruonn]

Ferdinand Magellan (Fernão Magalhães), was Portuguese, but made the trip in service of the kings of Castela (Spain). Keep up with the amazing work, you rock.

[@ericstarszak2076]

Hello from Mountain Time!! Colorado. Big fan. My dad was a math minor and Physics major so I grew up liking this stuff!

[@sk3.1415]

Chuck is very spontaneous and funny 😍. Thanks guys for educating the world.

[@rickantoine9799]

Y'all are so funny! Love laughing along with you! Can hardly go 30 seconds without chortling!

[@Jesse-cw5pv]

I was born on the east coast and moved to the west coast in grade school. And because i had family in both time zones it was easy to remember time zones

[@SingCity406]

Great job! That definitely helped! Funny as heck too!!

[@Mikaci_the_Grand_Duke]

Sorry guys but this time you made a misstake. They thought it was Wednesday but it was Thursday. They "lost a day"! 😉 I also missed a bit more explanation this time, beacuse I think many would ask, how is it, that Magellan's ship lost a whole day, was the time passing faster for them? Here is my explanation for those, who don't understand how it works. If you travel towards west, your days are going to be longer, beacuse you travel in the same direction as the sun goes (opposit way of the earth rotation). You are going to see the sun longer every day, because you travel "togeher" with the sun, so as a result your days are going to be longer than 24 hours. The sunset is also happening somewhat later for you, and the the sunrise too. Here is an example. Lets assume we have a time period of 10 days that means 240 hours to travel around the world towards west. But as I said for those who are travellig, the days are going to be longer, for exampe instead of 24 hours 26.67 hours in average. Now if you divide that original 240 hours (10 normal days) with 26.67 you get 9 nine days instead of 10. That is how for Magellan's crew seemingly passed 1 day less, because their days were longer than 24 hours, still the time was passing the same way for everybody.

[@sabbilon4542]

power of peer review

[@aleksandaraleksandrov4705]

Sometimes even a professor can be wrong.

[@TropicalVibesHD]

Good catch!

[@Mikaci_the_Grand_Duke]

@@TropicalVibesHD I was thinking about the missing detailed explanation, and I thought I was really dumb, because it didn't fit to the story explained in the video. I double-checked the facts and it turned out that I was right. However, it's only those who do nothing that make no mistakes. Much more important is the story and the scientific thoughts behind it.

[@jeffreychilcott223]

I was thinking the same thing. If the man on the boat logged each day at around noon, the sun would pass overhead 1 less time for him than someone who stayed in Portugal. The traveler would have slightly longer days and therefore, fewer of them. Easy mistake to make, even for the best and brightest.

[@kristinholcombe5133]

Welcome Back Chuck!!! We missed you 🎉

[@a.aguilar]

Just a few things for those that can be curious: - Fernando Magallanes was portuguese, but he did the trip to the orders of the Castillian king. It's almost sure that he was ordered as a castillian citizen before starting the journey. - The jurney started with 5 ships - They went from Spain (Seville IIRC) down the Guadalquivir river to Sanlucar de Barrameda and then heading west to America, were they discovered the Strait of Magellan. They knew there were another sea (the South Sea in that era). The first eurepean to see that "sea" was Vasco Nuñez de Balboa. - One of the ships shinked before the strait discovery. - Another ship returned to Spain also before the discovery, because many sailors thhought that that strait existed. - They called the "South sea" Pacifico, because when they went into it the water was very calm. They didn't know anything about that sea, and they sailed for several months without seing land. Many died or fell ill with scurvy. - After sailing beyond Phillipines, one ship had to be abandoned due ti its bad conditions andl almost shink for being loaded too much with species. - One more ship was captured by the portuguese army. The crew spent many years in prison doing forced labor and most died in prison. - Magellan died in a Phillipine island. He was replaced by another portuguese captain but for several reasons I can't explain here, he was replaced and finally it was Juan Sebastián Elcano who took the ship back to Spain. It's a very interesting story that is worth reading,.

[@tonykeltsflorida]

Arizona stays on Mountain Standard Time. I lived in Tucson for a while. Now I live in Florida where they are trying to get the state to approve staying on Eastern Daylight Time because it makes sense for this area. In November the night falls very early on standard time.

[@tampabayj]

And I always thought the International Date Line is when I date online in another country. 😅

[@lemongavine]

Haha. You’re goofy….in a good way.

[@occheermommy]

Arizona is only on Mountain Time part of the year because they dont fall back in the winter. The rest of the year they are on Pacific Time. Which we should all give up Daylight savings time but that is another story.

[@martypiraino8721]

Arizona is NEVER in or part of pacific time, people make this error all the time. There is a small part of Arizona that does observe daylight saving time that matches mountain daylight time with those states that are in the mountain time zone in the US "spring forward", the rest of Arizona including Flagstaff, Phoenix and Tucson are on mountain standard time year round. We don't change our clocks and we don't change time zones, it's just that when pacific time zone changes to pacific daylight time for the summer the time is the same on the clock as mountain standard time is during that part of the year. The pacific time zone "falls back" to pacific standard time in the winter months. You may also be surprised to know that Hawaii doesn't change their clocks either, or maybe not so surprised.

[@occheermommy]

@@martypiraino8721 ok I get what you’re saying but I feel like my way of putting it was probably easier to understand even if it’s not exactly by the book.

[@blue9multimediagroup]

​@occheermommy no it wasn't because it was incorrect

[@ostekuste3646]

I travelled to Australia on December 24th. It is a long flight, and crossing the International Date Line I actually missed December 25th and landed on December 26th in Sydney.

[@ATLJonathanH]

These two together are absolute perfection!

[@jayp7787]

Chuck is hilarious…but Neil laughing at Chuck’s jokes is funnier than the actual jokes

[@svscared]

My thoughts exactly. Love the way Chuck makes Neil constantly giggle 😂

[@sherryk6703]

Nah! His giggles are forced.

[@tigwhite883]

Chuck always adds some fun to each episode.

[@upperechelon3456]

You two make a great team. Chuck is thoroughly enjoyable and adds to learning process in my opinion. 😅

[@michaelmambo5177]

This episode educated me and cured my depression at the same time....love this team

[@noriokushi-dn7nl]

In the Fall of 1972 I took a ship from San Francisco to Yokohama, Japan. During the voyage, while crossing the middle of the Pacific Ocean, the calendar went from September 30th to November 2nd.

[@jerryclasby9628]

Love the interplay between these two

[@mike-zl3kv]

Chuck was right in referencing the Verne novel. Phileas Fogg experienced exactly the same phenomena in reverse when he went around the world in 80 days by his perception, but in 79 days local London time. All of the Pacific Time Zone (UTC-8) becomes part of the Mountain Time Zone (UTC-7) when it switches to Daylight Savings Time. Do a segment exploring all of the weird time zone peculiarities, like the two-hour time zones of Russia, the unitary time zone of China, the confusion in US Four Corners area, or the ridiculously independent time zones of Australia.

[@hollymeyer1343]

Arizona is in Mountain time for only half the year, the other half we're Pacific.

[@occheermommy]

I commented the same thing. I lived there for 5 years. It made so much more sense not to follow Daylight savings time. I wish we all didnt

[@TheSilverShadow17]

​@@occheermommyI wish we all never had DST or followed it either, and that's coming from someone who lives in Southwestern Kansas lol

[@AlfaMist-mf6rj]

You have too much ❤fun . I enjoy spending time with you. Thanks for taking your time schooling us on stuff our previous professors managed to make us snooze , lol 😂 btw. I appreciate the chemistry bw you.

[@raymondst.jacques2030]

Graphics, for me the first time i see graphics, photos, visual aids: thank you. 🤯👍👏🎉😎

[@Neliswa24]

I love you guys! I love the banter I love the chemistry between you and I love the delightful way I’m learning. ❤😂

[@q8386]

Great video, Neil and Chuck. Interesting and entertaining. Only this at 02:16: it's 'Magellan' no 'd'.

[@Anuchan]

I grew up in El Paso, which is in Mountain Time Zone even though the rest of Texas is in Central. All of our programming was delayed one hour so we watched the shows at the same time as listed for Central, even though it was actually an hour later.

[@emilymann1175]

Interesting, I wonder if that is why they used to say (here on the east coast) a certain show will be on at "8; 7 central and mountain" I always thought, how can it be on at the same time in central AND mountain? Shouldn't it be "and 6 mountain" but I think you've just answered something I've always wondered! Thanks, it's the little things ya know.

[@SavageDarknessGames]

In Canada almost all of Albertans live in Mountain Time: Calgary, Edmonton and all surrounding cities, hamlets, and towns / rural areas and farms. Then a few are in Pacific. also I believe all the way into Saskatchewan is also Mountain Time.

[@IamGroot786]

It's just interesting stuff to think about. When I was in the Navy and we sailed across the Atlantic Ocean towards Europe that first time for me, it was weird to continuously lose those hours.

[@ScottRobinson76]

I worked at a TV station in Boise, Mountain Time zone. East, Central time zone played shows live. West (Pacific Time) had their own feed. Mountain Time Zone, we had to tape delay shows by 1 hour so prime time didn't start at 6pm.

[@achesley43]

Yea for the fast forward button. Love the information part.

[@jajuanrussell5386]

Okay. In reference to the noon time discussion: I live in North Carolina, US of A, and in 2003, noon was roughly about 12:15 pm. You could discern noon by the lack of shadows being cast. I lived in Texas for about 8 years, and then returned to my hometown in North Carolina in 2011. When I returned home, I noticed that noon had shifted to about 2:00 pm. Presently, it is 2023, and noon appears to be occurring between 2:50 and 3:15 pm around the Raleigh. I am making note of the lack of shadows being cast on the ground. Furthermore, I have noticed that the seasons have shifted about 40 days after the designated calender days. Our winters seem to actually begin at the end of December; specifically in the last 10 days of December. Spring seems to begin in the last week of March or the first week of April, consistently for the past few years. Summer seems to start on time still, but fall doesn't actually begin until around Halloween time, days before or after. Summer time seems to be the longest season, where I live, for about past 11 years.

[@robertadams6606]

Yes even with in a Time Zone depending on where you are it will change, if you are in the western part of your Zone Sunrise & Sunset will be different from someone in the Eastern part of the Zone. If you live in the area of the Georgia/Alabama line they say late Time or Early Time.

[@Life_42]

You two are so awesome!

[@JeffKaylin-ft5cx]

I've been thinking about sundials, and what the error bars are for each aspect of them. So, can you point them to true North? Can you get the precise angle of the gnomon? If the dial is flat on the ground, then how do you warp the numbers around? And what about my position in my timezone (plus daylight savings)? Then there is the analemma and how much does that change the time? (although I can't really eyeball anything to more than 2 and a half digits.) I suspect that pointing true North is the most important adjustment.

[@laningwa]

Best and very entertaining talks..

[@Kingjaffeyjojo2900]

Great topic 🎯💯🙌

[@TreStylz]

So glad Chuck is back! 🎉

[@SpaceMiner007]

Sunrise East sunset West. On a new dock job in Long Beach, Cal harbor We started work every morning at 7:00, but because of the state's curvature the sun rose in the south over the ocean, but at quitting time, the sun would set to the north over the ocean as well! In those winter months.

[@markcaesar4443]

I do reconstructing time zones in shorthand. I know the Eastern States of Australia are "later" than the West and that solves that. My tme zone is GMT+8, Perth, Wester Australia

[@ContinentalDrifter]

I’m currently in Spain and while I was in Getaria on the northern coast, in Basque Country, I was told that hometown hero Juan Sebastián Elcano was the captain of the one and only of Magellan’s ships to actually return and so should be considered the first to complete a circumnavigation of the world. And although Magellan was Portuguese they left from, and returned to, Spain.

[@NoName-ik2du]

As a child, I didn't understand how the international dateline worked, so I was convinced that you could speed up time by moving with the rotation of the earth and slow down time by moving against the rotation of the earth. I also was also confused why you couldn't travel back in time by moving against the rotation of the earth at a speed faster than the earth was rotating.

[@soupytwist8737]

You guys…….😂. I love the way you bring education to the masses through intelligence and humour. Love it!

[@Nate-hw1nc]

Thank goodness the boys are back!!

[@professorsogol5824]

Please note the thumbnail for this explanation is incorrect: If the region of Asia marked to "Today" is marked correctly, then the region of North America marked "Tomorrow" should be marked either "Yesterday" or "Earlier Today." Under no circumstance can that region be "Tomorrow."

[@Hummy-gu1th]

I love these two together so damn much 😂😂

[@kurt6497]

For the people in Portugal it would have been Thursday, not Tuesday, as Magellan's ship going west would have extended their days by a little each day, thus having lost a day upon their return.

[@kurt6497]

The fictional Phileas Fogg went east, so he gained a day and won his bet. That was the point of the story.

[@oaguilera81]

LMAO what an amazing episode. These guys have a great chemistry 😂😂

[@charlesjones7063]

Loved it. Magellen was "killed" near Mactan, near the second largest city in the Philippines. Went there and saw the cross he planted on the beach. Good diving by the way!

[@stevenreyes3680]

I noticed the funny thing about mountain time, back in the day, Jonny Carson come on early, like 9pm ? So in their desolation, they just had to go to bed early ?

[@franknomustard]

That Episode, was hysterical! I don’t usually laugh out loud at science programs! Wow that was both funny and informative!

[@JohnCater5]

… and in several places… simply WRONG! If you want to understand the IDL, don’t watch this. The thumbnail is wrong. And at about 5:00 minutes, they get the Tuesday/Wednesday thing the wrong way round.

[@BiGprOtein65g]

Funniest thing about these episodes is that I always come in with alot of questions but they all get answered

[@jonathancamp7190]

Traveling back & forth between the US and Japan, I've crossed the Internation Date Line 8 times. Currently, I reside in Mountain Time Zone, UTC -7.

[@briangrimshaw6086]

I am from Montana and you guys are right we never get mention at all. But we like that

[@scotwkilgrow]

Neil thanks. I'm 67, your opening my knowledge, perspectives of our planet.

[@JohnCater5]

If you want to understand the IDL, don’t watch this. The thumbnail is wrong. And at about 5:00 minutes, they get the Tuesday/Wednesday thing the wrong way round.

[@michaelccopelandsr7120]

Spent a season crab fishing out of Dutch Harbor, Alaska. It's about an hour away from the International Date Line at the end of the Aleutian islands. Or as they say there, "It's not the end of the world but you can see it from here." Good times. ;-P

[@acedriver142]

With what happened recently you should do an explainer video on Ocean pressure why the pressure is greater the deeper you go

[@cantordavid613]

The configuration of time zones in the U.S. was *heavily* influenced by the railroad industry in the 19th century, in order to better manage departures and arrivals. It is likely at least part of the reason why the Mountain Time zone is the shape it is.

[@asan1050]

Thanks Much !.......yes

[@blackraven4842]

I wish I had a friend like Dr. Tyson has Chuck

[@anntaylor4027]

I can't believe Neil got the date paradox backwards: "[The ship's navigator] thinks it's Wednesday and everyone there [at Cape Verde] thinks it's Tuesday". It actually was the opposite: "Upon arrival at Cape Verde, the crew was surprised to learn that the ship's date of 9 July 1522 was one day behind the local date of 10 July 1522, even though they had recorded every day of the three-year journey without omission. They lost one day because they travelled west during their circumnavigation of the globe, in the same direction as the apparent motion of the sun across the sky" (wikipedia Magellan Expedition).

[@DustInTheWindAZ]

In regards to the "sub-discussion" of the "Mountain Time Zone" and why it isn't mentioned (any longer) for TV broadcasts: In the "early" days of television, when everything was done "live", networks DID announce separate times for the 4 time zones, because it was "real time". With the advancement of technology, and tape-delay in particular, the networks could transmit programming to each of the individual affiliates to have them broadcast programs "in local time"; i.e. "Prime Time" was the same in all time zones. This also explains or adjusts Prime Time for those places (i.e. most of Arizona) who do not observe Daylight Saving Time. Although AZ is in the Mountain Time Zone, we do not adjust adjust our clocks twice a year, so that during the summer months we have the same "time" as Pacific Time Zone (Mountain Standard Time = Pacific Daylight Time). Have you never been to Hoover Dam in the summer and wonder why the clock on the towers have the same time in different time zones (for "half" the year)? So then, is time absolute, or is it geo-political? Obviously, it is BOTH! We cannot change the "passage" of time", but we CAN change how we "control" it! Only the longitudinal lines of Earth are true to "real" time (that's how they came to be). But time ZONES are man-made. So then.... why are some Middle-Eastern times zones offset by 30 or 45 minutes? In a word, "politics"! Time is a paradox.

[@jpdemer5]

I recall TV programs being announced with Eastern, Central, and "Pacific/Mountain" times.

[@DustInTheWindAZ]

@@jpdemer5 So do I; hence the reply above.

[@Jordy-927]

I sailed acrossed the international date line a few times in the Navy.