The Discovery of the Celendrical Date Line

Spoiler alerts but this exactly the plot twist at the end of the book "Around the World in 80 Days" by Jules Verne

https://en.wikipedia.org/wiki/Around_the_World_in_Eighty_Day...

The following day Fogg apologises to Aouda for bringing her with him since he now has to live in poverty and cannot support her. Aouda confesses that she loves him and asks him to marry her. As Passepartout notifies a minister, he learns that he is mistaken in the date – it is not 22 December, but instead 21 December. Because the party had travelled eastward, their days were shortened by four minutes for every degree of longitude they crossed; thus, although they had experienced the same amount of time abroad as people had experienced in London, they had seen 80 sunrises and sunsets while London had seen only 79. Passepartout informs Fogg of his mistake and Fogg hurries to the Club just in time to meet his deadline and win the wager. Having spent almost £19,000 of his travel money during the journey, he divides the remainder between Passepartout and Fix and marries Aouda.

It is not only sailors who get confused going around the world. The lightning map on the WeatherBug site and in the WeatherBug iOS/iPadOS app gets confused if you scroll all the way around.

When opened in the US the map is centered on the US. Scroll east to bring Europe and Africa into view and it shows lightning there. Keep scrolling east to see lighting in Asia and beyond.

When you come all the way around and the US comes into view there is no lightning. Keep going east and Europe and Africa and Asia have no lightning.

Go around east a few mores times. Then reverse direction. You've got to go around west the same number of times you went around east to get the lightning back.

For US users who want to check lighting in Europe or Africa this probably won't cause problems. They will most likely scroll east.

But for US users who want to check lighting in say Japan or Australia they will probably scroll west, and there will be no lightning. To see lighting in Japan or Australia US users have to scroll east past Europe.

Interestingly, the date line wasn't always where it is now. For example if you look at the tz database it has Asia/Manila with an offset of -15:56 until 1844; that's because the Philippines were actually colonized from Mexico, so they kept the same day count as the Americas. (https://webspace.science.uu.nl/~gent0113/idl/idl_philippines...). But as they came to be more integrated with their geographical neighbors they switched to counting the days like them.

Similarly tz has time zones as far east as +15:13:42 for Metlakatla in far south eastern Alaska, until 1867, since Alaska was settled from Russia. I think these are basically the furthest east and west the date line ever went (although maybe the Russians made it further south and east along the west coast of North America?)

Obligatory Umberto Eco plug: https://en.wikipedia.org/wiki/The_Island_of_the_Day_Before

Hopefully Eco + the title is enough but if it helps IMO it’s arguably his best work. All of the stepwise logic leading to madness of Name of the Rose and Foucault’s pendulum, a somewhat less slapstick sensibility than either, without descending into dryness as his later work. Super recommended.

The 'lost day' occurred because the expedition had been traveling westward, in the same direction as the Sun. As they circled the globe, they were effectively chasing the Sun, which meant that each day was slightly longer than 24 hours. Over the course of their journey, these small increments added up to a full day. Thus, by the time they completed their circumnavigation, they had 'lost' one day compared to those who remained in one location.

I like the concept of chasing the sun. That should be a metaphor.

Wikipedia says the international date line is “a cartographic convention, and is not defined by international law.”

The “line” wasn’t a convention at all in the 16th century so how did sailors experience loss of a day?

https://en.m.wikipedia.org/wiki/International_Date_Line#:~:t....

I wonder how the discovery of the need of this International Date Line influence not just navigation and timekeeping, but also the understanding of experience of the flow of time, did it perhaps influence the Englightment, as it just occured before, or was it the age of discovery of the Americas and the Pacific? Difficult to seperate.

A Romanian girl called Iliana/Ilana from Galati or Brailia I was in love with long ago recommended me Umberto Eco's The Island of the Day before when I met her in Taize. Sadly I lost her contact data and her lastname, forever lost in the day before.

I wonder if Pigafetta's account was the inspiration for the ending of Jules Verne's "Around The World In Eighty Days"?

It's a typo - it should be Calendrical.

See https://webspace.science.uu.nl/~gent0113/idl/idl.htm

I'm surprised this is still up. The UU has been on a quest of destroying all web pages hosted under uu.nl domain that are not managed by "the cloud", Office365 or blackboard with the argument of "its not gdpr compliant". All the old personal web pages of professors of the CS department (cs.uu.nl) have already been purged in the name of "compliance". Decades of Internet History and science just wiped because of somebody's career fetish. Seems the math department had more backbone than the computer science department.

I wrote a bot that archived it all and it's on my old university laptop still. Lots of gems, blog posts, articles that were all just deleted. I still need to upload it somewhere