<?xml version="1.0" encoding="UTF-8"?><rss xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:content="http://purl.org/rss/1.0/modules/content/" xmlns:atom="http://www.w3.org/2005/Atom" version="2.0" xmlns:itunes="http://www.itunes.com/dtds/podcast-1.0.dtd" xmlns:googleplay="http://www.google.com/schemas/play-podcasts/1.0"><channel><title><![CDATA[Number Trails by Tanay Sukumar]]></title><description><![CDATA[All the various forms numbers take—and why they thrill me.]]></description><link>https://www.tanaysukumar.in</link><image><url>https://substackcdn.com/image/fetch/$s_!tiuG!,w_256,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fd0b8dfb1-6856-44a5-bd36-360bacc5525d_707x707.png</url><title>Number Trails by Tanay Sukumar</title><link>https://www.tanaysukumar.in</link></image><generator>Substack</generator><lastBuildDate>Fri, 03 Apr 2026 20:35:36 GMT</lastBuildDate><atom:link href="https://www.tanaysukumar.in/feed" rel="self" type="application/rss+xml"/><copyright><![CDATA[Tanay Sukumar]]></copyright><language><![CDATA[en]]></language><webMaster><![CDATA[tanaysukumar@substack.com]]></webMaster><itunes:owner><itunes:email><![CDATA[tanaysukumar@substack.com]]></itunes:email><itunes:name><![CDATA[Tanay Sukumar]]></itunes:name></itunes:owner><itunes:author><![CDATA[Tanay Sukumar]]></itunes:author><googleplay:owner><![CDATA[tanaysukumar@substack.com]]></googleplay:owner><googleplay:email><![CDATA[tanaysukumar@substack.com]]></googleplay:email><googleplay:author><![CDATA[Tanay Sukumar]]></googleplay:author><itunes:block><![CDATA[Yes]]></itunes:block><item><title><![CDATA[The search for a calendar that can win the day—but also the year]]></title><description><![CDATA[Calendar systems have never been perfect. The one we use has absurdities, too. In this post, I discuss why it&#8217;s time for a new, simple, permanent calendar that can work for everyone.]]></description><link>https://www.tanaysukumar.in/p/the-search-for-a-calendar-that-can</link><guid isPermaLink="false">https://www.tanaysukumar.in/p/the-search-for-a-calendar-that-can</guid><dc:creator><![CDATA[Tanay Sukumar]]></dc:creator><pubDate>Fri, 20 Mar 2026 10:40:57 GMT</pubDate><enclosure url="https://images.unsplash.com/photo-1611988615248-5d4f0b9ac31e?fm=jpg&amp;q=60&amp;w=3000&amp;auto=format&amp;fit=crop&amp;ixlib=rb-4.1.0&amp;ixid=M3wxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8fA%3D%3D" length="0" type="image/jpeg"/><content:encoded><![CDATA[<p>Imagine if your birthday were to fall on the same day every year: no fuss at all over trying to make different plans each year based on the new calendar. Think of the same for your anniversary, or Christmas, or New Year. Scheduling annual exams and monthly workplace team rosters would become a whole lot easier. As you&#8217;d get older, perhaps you might even end up knowing by heart which day any given date falls, whatever be the year.</p><p>Well, this ideal scenario is not really implausible. True, the year needs to be 365 or 366 days long to keep it in sync with how the earth moves, and neither number is divisible by 7, so you end up taking for granted that the first of January must shift days every year. But the multiplication table of 7 is just a tiny inconvenience in the larger scheme of things. Ways have been proposed to get past it and have one permanent calendar, once and for all.</p><div class="subscription-widget-wrap-editor" data-attrs="{&quot;url&quot;:&quot;https://www.tanaysukumar.in/subscribe?&quot;,&quot;text&quot;:&quot;Subscribe&quot;,&quot;language&quot;:&quot;en&quot;}" data-component-name="SubscribeWidgetToDOM"><div class="subscription-widget show-subscribe"><div class="preamble"><p class="cta-caption">Thanks for reading Number Trails by Tanay Sukumar! Subscribe for free to get future posts on email.</p></div><form class="subscription-widget-subscribe"><input type="email" class="email-input" name="email" placeholder="Type your email&#8230;" tabindex="-1"><input type="submit" class="button primary" value="Subscribe"><div class="fake-input-wrapper"><div class="fake-input"></div><div class="fake-button"></div></div></form></div></div><p>We can intuitively predict how the hours, minutes and seconds will progress on an unknown day 20 years hence. We can quickly tell which year it will be 40 years from now. But to know the day a particular date will fall even one month later, we don&#8217;t feel sure unless we&#8217;ve referred to a calendar. Can this get more absurd?</p><div class="captioned-image-container"><figure><a class="image-link image2 is-viewable-img" target="_blank" href="https://images.unsplash.com/photo-1611988615248-5d4f0b9ac31e?fm=jpg&amp;q=60&amp;w=3000&amp;auto=format&amp;fit=crop&amp;ixlib=rb-4.1.0&amp;ixid=M3wxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8fA%3D%3D" data-component-name="Image2ToDOM"><div class="image2-inset"><picture><source type="image/webp" srcset="https://images.unsplash.com/photo-1611988615248-5d4f0b9ac31e?fm=jpg&amp;q=60&amp;w=3000&amp;auto=format&amp;fit=crop&amp;ixlib=rb-4.1.0&amp;ixid=M3wxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8fA%3D%3D 424w, https://images.unsplash.com/photo-1611988615248-5d4f0b9ac31e?fm=jpg&amp;q=60&amp;w=3000&amp;auto=format&amp;fit=crop&amp;ixlib=rb-4.1.0&amp;ixid=M3wxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8fA%3D%3D 848w, https://images.unsplash.com/photo-1611988615248-5d4f0b9ac31e?fm=jpg&amp;q=60&amp;w=3000&amp;auto=format&amp;fit=crop&amp;ixlib=rb-4.1.0&amp;ixid=M3wxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8fA%3D%3D 1272w, https://images.unsplash.com/photo-1611988615248-5d4f0b9ac31e?fm=jpg&amp;q=60&amp;w=3000&amp;auto=format&amp;fit=crop&amp;ixlib=rb-4.1.0&amp;ixid=M3wxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8fA%3D%3D 1456w" sizes="100vw"><img src="https://images.unsplash.com/photo-1611988615248-5d4f0b9ac31e?fm=jpg&amp;q=60&amp;w=3000&amp;auto=format&amp;fit=crop&amp;ixlib=rb-4.1.0&amp;ixid=M3wxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8fA%3D%3D" width="3000" height="2000" data-attrs="{&quot;src&quot;:&quot;https://images.unsplash.com/photo-1611988615248-5d4f0b9ac31e?fm=jpg&amp;q=60&amp;w=3000&amp;auto=format&amp;fit=crop&amp;ixlib=rb-4.1.0&amp;ixid=M3wxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8fA%3D%3D&quot;,&quot;srcNoWatermark&quot;:null,&quot;fullscreen&quot;:null,&quot;imageSize&quot;:null,&quot;height&quot;:2000,&quot;width&quot;:3000,&quot;resizeWidth&quot;:null,&quot;bytes&quot;:null,&quot;alt&quot;:&quot;white calendar on white textile&quot;,&quot;title&quot;:&quot;white calendar on white textile&quot;,&quot;type&quot;:null,&quot;href&quot;:null,&quot;belowTheFold&quot;:false,&quot;topImage&quot;:true,&quot;internalRedirect&quot;:null,&quot;isProcessing&quot;:false,&quot;align&quot;:null,&quot;offset&quot;:false}" class="sizing-normal" alt="white calendar on white textile" title="white calendar on white textile" srcset="https://images.unsplash.com/photo-1611988615248-5d4f0b9ac31e?fm=jpg&amp;q=60&amp;w=3000&amp;auto=format&amp;fit=crop&amp;ixlib=rb-4.1.0&amp;ixid=M3wxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8fA%3D%3D 424w, https://images.unsplash.com/photo-1611988615248-5d4f0b9ac31e?fm=jpg&amp;q=60&amp;w=3000&amp;auto=format&amp;fit=crop&amp;ixlib=rb-4.1.0&amp;ixid=M3wxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8fA%3D%3D 848w, https://images.unsplash.com/photo-1611988615248-5d4f0b9ac31e?fm=jpg&amp;q=60&amp;w=3000&amp;auto=format&amp;fit=crop&amp;ixlib=rb-4.1.0&amp;ixid=M3wxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8fA%3D%3D 1272w, https://images.unsplash.com/photo-1611988615248-5d4f0b9ac31e?fm=jpg&amp;q=60&amp;w=3000&amp;auto=format&amp;fit=crop&amp;ixlib=rb-4.1.0&amp;ixid=M3wxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8fA%3D%3D 1456w" sizes="100vw" fetchpriority="high"></picture><div class="image-link-expand"><div class="pencraft pc-display-flex pc-gap-8 pc-reset"><button tabindex="0" type="button" class="pencraft pc-reset pencraft icon-container restack-image"><svg role="img" width="20" height="20" viewBox="0 0 20 20" fill="none" stroke-width="1.5" stroke="var(--color-fg-primary)" stroke-linecap="round" stroke-linejoin="round" xmlns="http://www.w3.org/2000/svg"><g><title></title><path d="M2.53001 7.81595C3.49179 4.73911 6.43281 2.5 9.91173 2.5C13.1684 2.5 15.9537 4.46214 17.0852 7.23684L17.6179 8.67647M17.6179 8.67647L18.5002 4.26471M17.6179 8.67647L13.6473 6.91176M17.4995 12.1841C16.5378 15.2609 13.5967 17.5 10.1178 17.5C6.86118 17.5 4.07589 15.5379 2.94432 12.7632L2.41165 11.3235M2.41165 11.3235L1.5293 15.7353M2.41165 11.3235L6.38224 13.0882"></path></g></svg></button><button tabindex="0" type="button" class="pencraft pc-reset pencraft icon-container view-image"><svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-maximize2 lucide-maximize-2"><polyline points="15 3 21 3 21 9"></polyline><polyline points="9 21 3 21 3 15"></polyline><line x1="21" x2="14" y1="3" y2="10"></line><line x1="3" x2="10" y1="21" y2="14"></line></svg></button></div></div></div></a><figcaption class="image-caption">Credit: <a href="https://unsplash.com/photos/white-calendar-on-white-textile-jqxB3C0YNG0">Kyrie Kim/Unsplash</a></figcaption></figure></div><p>You see, the kind of shifting calendar we currently use&#8212;and which we are used to the way we are to the air and water around us&#8212;is one of the oldest surviving ways of organising life, and it has seen little change for centuries. Rather, it has spread across the world with little resistance and evolution, as it helps unify humanity like few other things. We may have different languages and customs, but we operate with the same calendar to keep life smooth. Traditional and religious calendars may dictate local festivals, but the January 1 to December 31 cycle is so ingrained that not following it would cause chaos. The last time someone made a tweak to the calendar, <a href="https://www.historic-uk.com/HistoryUK/HistoryofBritain/Give-us-our-eleven-days/">countries saw riots</a>.</p><p>So should we expect any massive change that could fundamentally change how we count our days? Well, not right now; though the world has been much closer to a calendar revolution in the 20th century (which I will come to in a bit). Let me argue why it would be nice to revive the debate.</p><p>The calendar we so intimately know is a sun-based one, called the Gregorian calendar, and has been in use since 1582, when Pope Gregory XIII decided to revamp the Julian calendar that was in existence back then. The older calendar, which Roman emperor Julius Caesar formalised more than 2,000 years ago in 45 BCE, was actually pretty much the same as what we know the calendar to be: it only counted three extra days every 400 years. In that sense, Gregory&#8217;s innovation in how we structure our calendar was marginal.</p><p>The flaw with Caesar&#8217;s calendar was that its three extra days every 400 years made it a bit too slow. Over the centuries, the equinoxes were not falling on their expected dates any longer, and if left unchanged, dates would begin to fall out of sync with the seasons. So Gregory&#8217;s innovation set it right by deciding that century years that don&#8217;t divide by 400 would no longer be leap years. It isn&#8217;t perfect yet, but now the error will not make itself felt for thousands of years.</p><p>The basic structure of Caesar&#8217;s calendar (which, too, was inspired from the structure of the ancient Egyptian calendar) still thrives simply because we&#8217;re so used to it. Who finds it intuitive to have a short February, equal lengths of July and August, and the ever-changing day for any given date? If you forget that it&#8217;s an unavoidable way of life, you might realise it&#8217;s a ridiculous way to structure your year.</p><p>The structural flaws of the Julian calendar have their roots in arbitrary choices of Roman dictators. Their sole (and crucial) priority was to average 365.25 days a year (and 365.2425 a year in the Gregorian tweak) over longer periods, and rightly so. But they also had an eye on the traditional imperative to align festivals with the lunar months, leading to irregularly-sized months. Secondly, the Julian calendar, and its Gregorian innovation, are deeply rooted in religion, hardly in science. Gregory wasn&#8217;t out to impress the Renaissance vote bank; the problem was that scholars had complained for centuries that the choice of date for the annual Easter, which was linked to the March equinox, was falling out of line with the sun&#8217;s position in the sky. Also at play was rivalry with the Jewish calendar, which didn&#8217;t face the issue in scheduling its own equinox-linked festival Passover. The Christians simply wanted a foolproof method of their own.</p><p>So essentially what we currently use to dictate our rhythm of life is a calendar that could reform itself only out of religious compulsions, where scientificity was unintentional. It led to quarrels within Christianity; Britain (which had tense relations with the Vatican) didn&#8217;t adopt Gregory&#8217;s reforms until 1752, and the Russian Orthodox Church still uses the Julian calendar and is by now 13 days out of line with the earth&#8217;s motion! This deeply unsecular calendar then travelled the world solely by virtue of European colonialism. It doesn&#8217;t really need to run the 21st-century world.</p><p><strong>The world needs a secular calendar that can shed its religious and colonial baggage. A common calendar that pleases no religion, but works for all humans and makes date-counting&#8212;its basic purpose&#8212;easier.</strong></p><p>The World Calendar, my favourite alternative, was proposed in the 20th century, and it made it close in debates at the United Nations. It retains the same 12 months. January 1 always falls on a Sunday. Each quarter is made up of months 31, 30 and 30 days long. That adds up to 91 days, or exactly 13 weeks, which means that each quarter, not just each year, starts and ends on the same day. The cycle of days and dates repeats every quarter, unlike every 28 years like now (our current calendar normally repeats every 28 years due to the leap year), making it easier to remember days. You wouldn&#8217;t need to change calendars every year!</p><div class="captioned-image-container"><figure><a class="image-link image2 is-viewable-img" target="_blank" href="https://substackcdn.com/image/fetch/$s_!9QYO!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F41cc2c90-0bc5-4053-9d74-d5430ac226ca_960x960.png" data-component-name="Image2ToDOM"><div class="image2-inset"><picture><source type="image/webp" srcset="https://substackcdn.com/image/fetch/$s_!9QYO!,w_424,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F41cc2c90-0bc5-4053-9d74-d5430ac226ca_960x960.png 424w, https://substackcdn.com/image/fetch/$s_!9QYO!,w_848,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F41cc2c90-0bc5-4053-9d74-d5430ac226ca_960x960.png 848w, https://substackcdn.com/image/fetch/$s_!9QYO!,w_1272,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F41cc2c90-0bc5-4053-9d74-d5430ac226ca_960x960.png 1272w, https://substackcdn.com/image/fetch/$s_!9QYO!,w_1456,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F41cc2c90-0bc5-4053-9d74-d5430ac226ca_960x960.png 1456w" sizes="100vw"><img src="https://substackcdn.com/image/fetch/$s_!9QYO!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F41cc2c90-0bc5-4053-9d74-d5430ac226ca_960x960.png" width="960" height="960" data-attrs="{&quot;src&quot;:&quot;https://substack-post-media.s3.amazonaws.com/public/images/41cc2c90-0bc5-4053-9d74-d5430ac226ca_960x960.png&quot;,&quot;srcNoWatermark&quot;:null,&quot;fullscreen&quot;:null,&quot;imageSize&quot;:null,&quot;height&quot;:960,&quot;width&quot;:960,&quot;resizeWidth&quot;:null,&quot;bytes&quot;:null,&quot;alt&quot;:&quot;undefined&quot;,&quot;title&quot;:null,&quot;type&quot;:null,&quot;href&quot;:null,&quot;belowTheFold&quot;:true,&quot;topImage&quot;:false,&quot;internalRedirect&quot;:null,&quot;isProcessing&quot;:false,&quot;align&quot;:null,&quot;offset&quot;:false}" class="sizing-normal" alt="undefined" title="undefined" srcset="https://substackcdn.com/image/fetch/$s_!9QYO!,w_424,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F41cc2c90-0bc5-4053-9d74-d5430ac226ca_960x960.png 424w, https://substackcdn.com/image/fetch/$s_!9QYO!,w_848,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F41cc2c90-0bc5-4053-9d74-d5430ac226ca_960x960.png 848w, https://substackcdn.com/image/fetch/$s_!9QYO!,w_1272,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F41cc2c90-0bc5-4053-9d74-d5430ac226ca_960x960.png 1272w, https://substackcdn.com/image/fetch/$s_!9QYO!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F41cc2c90-0bc5-4053-9d74-d5430ac226ca_960x960.png 1456w" sizes="100vw" loading="lazy"></picture><div class="image-link-expand"><div class="pencraft pc-display-flex pc-gap-8 pc-reset"><button tabindex="0" type="button" class="pencraft pc-reset pencraft icon-container restack-image"><svg role="img" width="20" height="20" viewBox="0 0 20 20" fill="none" stroke-width="1.5" stroke="var(--color-fg-primary)" stroke-linecap="round" stroke-linejoin="round" xmlns="http://www.w3.org/2000/svg"><g><title></title><path d="M2.53001 7.81595C3.49179 4.73911 6.43281 2.5 9.91173 2.5C13.1684 2.5 15.9537 4.46214 17.0852 7.23684L17.6179 8.67647M17.6179 8.67647L18.5002 4.26471M17.6179 8.67647L13.6473 6.91176M17.4995 12.1841C16.5378 15.2609 13.5967 17.5 10.1178 17.5C6.86118 17.5 4.07589 15.5379 2.94432 12.7632L2.41165 11.3235M2.41165 11.3235L1.5293 15.7353M2.41165 11.3235L6.38224 13.0882"></path></g></svg></button><button tabindex="0" type="button" class="pencraft pc-reset pencraft icon-container view-image"><svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-maximize2 lucide-maximize-2"><polyline points="15 3 21 3 21 9"></polyline><polyline points="9 21 3 21 3 15"></polyline><line x1="21" x2="14" y1="3" y2="10"></line><line x1="3" x2="10" y1="21" y2="14"></line></svg></button></div></div></div></a><figcaption class="image-caption">World Calendar | Credit: Melikamp (<a href="https://commons.wikimedia.org/w/index.php?curid=157403633">Wikimedia Commons</a>)</figcaption></figure></div><p>But that adds up to 364 days, a day and a quarter too short. So it adds one extra date at the end of December&#8212;a global festival of sorts, Worldsday&#8212;that does not get either a day or a date. Every four years, to account for the leap year, we add a similar Worldsday at the end of June as well. Since Worldsday doesn&#8217;t get a day, the following January 1 or July 1 don&#8217;t fall out of cycle. Alongside, we get an extra day to celebrate a secular, simple calendar that governs our lives so intimately.</p><p>Of course, religion came in the way. The Monday to Sunday cycle is essential to some religions, and a date that doesn&#8217;t fall on any of these seven days would disturb that rhythm. Also, something that wasn&#8217;t perhaps a problem in the mid-20th century, the foundation of our current computer technology is entirely based on the Gregorian calendar, and a disruption to accommodate an unusual concept of Worldsday&#8212;a day that&#8217;s somewhat not a day&#8212;would bring chaos to digital systems.</p><p>Is there a way out? If you had to build a calendar from scratch, what would it look like? Do you have a solution, or would you rather continue with the current system? In terms of simplicity, it must win the day&#8212;but also the year (remember, that first and foremost, a solar calendar must stay in line with the seasons, with a year of accurate length).</p><p>Think about it, and please do write back. For now, it&#8217;s time to say goodbye, with the promise to write more about this topic, and to explore other alternative calendar systems, in my coming posts.</p><div class="subscription-widget-wrap-editor" data-attrs="{&quot;url&quot;:&quot;https://www.tanaysukumar.in/subscribe?&quot;,&quot;text&quot;:&quot;Subscribe&quot;,&quot;language&quot;:&quot;en&quot;}" data-component-name="SubscribeWidgetToDOM"><div class="subscription-widget show-subscribe"><div class="preamble"><p class="cta-caption">Thanks for reading Number Trails by Tanay Sukumar! Subscribe for free to receive new posts and support my work.</p></div><form class="subscription-widget-subscribe"><input type="email" class="email-input" name="email" placeholder="Type your email&#8230;" tabindex="-1"><input type="submit" class="button primary" value="Subscribe"><div class="fake-input-wrapper"><div class="fake-input"></div><div class="fake-button"></div></div></form></div></div>]]></content:encoded></item><item><title><![CDATA[The enchanting journey of calendars through the ages]]></title><description><![CDATA[Timekeeping and calendar systems are among the most fascinating but underrated sciences that we have tirelessly tried to perfect over the millennia. Here are two books to read on the topic.]]></description><link>https://www.tanaysukumar.in/p/the-enchanting-journey-of-calendars</link><guid isPermaLink="false">https://www.tanaysukumar.in/p/the-enchanting-journey-of-calendars</guid><dc:creator><![CDATA[Tanay Sukumar]]></dc:creator><pubDate>Sun, 18 Jan 2026 14:49:45 GMT</pubDate><enclosure url="https://substackcdn.com/image/fetch/$s_!fJT-!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F1e521fc0-52ef-4ebd-ac2e-3bafe0f57927_551x391.png" length="0" type="image/jpeg"/><content:encoded><![CDATA[<p>Calendars and timekeeping have always mesmerised me. At four, I would tell you the day any date fell at the drop of a hat. Time zones fascinated me so much for days that a reclusive boy like me went to a well-travelled relative just to ask him whether wristwatches adjusted themselves on flights to match their new location. The day my parents got me a &#8220;digital diary&#8221;, I stayed up till midnight just to catch the date changing in real time. (I considered doing the same on New Year&#8217;s Eve too, but didn&#8217;t.*).</p><p>It was only in recent years that I began to realise that this quirk wasn&#8217;t as trivial or childish as I thought. As it turns out, the history of the world itself intersects surprisingly often with the history of the calendar and timekeeping. Think about it: when there was nothing, there was time. It&#8217;s always moving, only in one direction, leaving you with no option but to measure it, somehow. Early humans didn&#8217;t have any option either: and they scrambled hard to figure it all out.</p><p>I just finished reading two breathtaking books: Chad Orzel&#8217;s <em>A Brief History of Timekeeping </em>(<a href="https://benbellabooks.com/shop/a-brief-history-of-timekeeping/">BenBella Books</a>, 2022) and David Ewing Duncan&#8217;s <em>Calendar </em>(<a href="https://www.harpercollins.com/products/calendar-david-ewing-duncan?variant=32117024489506">Avon Books</a>, 1998), and I&#8217;m truly spellbound at how the quest for accurate timekeeping has shaped humanity at all its stages&#8212;even when our prehistoric ancestors were largely clueless about the world. In this post, I share what I&#8217;m thinking right now as I chew on these books.</p><div class="captioned-image-container"><figure><a class="image-link image2 is-viewable-img" target="_blank" href="https://substackcdn.com/image/fetch/$s_!fJT-!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F1e521fc0-52ef-4ebd-ac2e-3bafe0f57927_551x391.png" data-component-name="Image2ToDOM"><div class="image2-inset"><picture><source type="image/webp" srcset="https://substackcdn.com/image/fetch/$s_!fJT-!,w_424,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F1e521fc0-52ef-4ebd-ac2e-3bafe0f57927_551x391.png 424w, https://substackcdn.com/image/fetch/$s_!fJT-!,w_848,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F1e521fc0-52ef-4ebd-ac2e-3bafe0f57927_551x391.png 848w, https://substackcdn.com/image/fetch/$s_!fJT-!,w_1272,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F1e521fc0-52ef-4ebd-ac2e-3bafe0f57927_551x391.png 1272w, https://substackcdn.com/image/fetch/$s_!fJT-!,w_1456,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F1e521fc0-52ef-4ebd-ac2e-3bafe0f57927_551x391.png 1456w" sizes="100vw"><img src="https://substackcdn.com/image/fetch/$s_!fJT-!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F1e521fc0-52ef-4ebd-ac2e-3bafe0f57927_551x391.png" width="551" height="391" 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class="pencraft pc-display-flex pc-gap-8 pc-reset"><button tabindex="0" type="button" class="pencraft pc-reset pencraft icon-container restack-image"><svg role="img" width="20" height="20" viewBox="0 0 20 20" fill="none" stroke-width="1.5" stroke="var(--color-fg-primary)" stroke-linecap="round" stroke-linejoin="round" xmlns="http://www.w3.org/2000/svg"><g><title></title><path d="M2.53001 7.81595C3.49179 4.73911 6.43281 2.5 9.91173 2.5C13.1684 2.5 15.9537 4.46214 17.0852 7.23684L17.6179 8.67647M17.6179 8.67647L18.5002 4.26471M17.6179 8.67647L13.6473 6.91176M17.4995 12.1841C16.5378 15.2609 13.5967 17.5 10.1178 17.5C6.86118 17.5 4.07589 15.5379 2.94432 12.7632L2.41165 11.3235M2.41165 11.3235L1.5293 15.7353M2.41165 11.3235L6.38224 13.0882"></path></g></svg></button><button tabindex="0" type="button" class="pencraft pc-reset pencraft icon-container view-image"><svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-maximize2 lucide-maximize-2"><polyline points="15 3 21 3 21 9"></polyline><polyline points="9 21 3 21 3 15"></polyline><line x1="21" x2="14" y1="3" y2="10"></line><line x1="3" x2="10" y1="21" y2="14"></line></svg></button></div></div></div></a></figure></div><p>Even when maths was scarce and the number system was in dinosaur age, there were the sun and the moon, mysteriously rising out of nowhere and turning off every day, acting as natural clocks, demanding to be tracked, <em>somehow</em>. And track we did&#8212;in ways small and big. It gave birth to a remarkable timeline of events, driven in turns by agriculture (think of the havoc farmers would be in if the calendar was linked to the moon and not the seasons), religion (think of the tensions it would create if two priests began arguing about when a festival should be held), and medieval imperialism (think of why the British Empire would announce a massive prize for anyone who could figure out how to measure longitudes&#8212;and hence time&#8212;at the sea, a real pain for scientists at that time).</p><p>The process ended up shaping everything from mathematics, physics and engineering to astronomy, geopolitics, and our GPS and satellite systems today. Innovations in each pushed all others ahead: humanity&#8217;s puzzles, across disciplines, almost always got their answers when we &#8216;timed&#8217; it right.</p><p>War&#8212;and love**&#8212;led to the basis for the calendar we use today. A major tweak to how we count days once led to a riot^. How to decide the date of Easter (and the imperative to avoid a method that mimicked the rival Jewish calendar) was the subject of hot debate and mathematical innovation for centuries. It&#8217;s truly revelatory to think of world history from the perspective of the calendar.</p><p>While I strongly recommend you read the books, here&#8217;s my list of three characters who impressed me the most (among many) along the journey:</p><pre><code><strong>Su Song:</strong> A Chinese polymath who designed the world&#8217;s first hydro-mechanical astronomical clock tower in the 11th century. Till then, something or the other was not quite working out as people everywhere tried to measure time. Su Song solved several issues with a clock that likely weighed in tonnes.</code></pre><pre><code><strong>Ruth Belville (aka Greenwich Time Lady):</strong> A British woman who visited the Royal Observatory in Greenwich to reset her watch every week and then went door-to-door to meet (and chat with) all her subscribers so that they could sync their devices with hers. (Yes, clocks would need to be synced that often even in the 20th century&#8212;and it could be a bona fide business idea!)</code></pre><div class="captioned-image-container"><figure><a class="image-link image2 is-viewable-img" target="_blank" href="https://substackcdn.com/image/fetch/$s_!DIFA!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fea20fa17-bddf-4ad1-bcdf-732d033ef687_654x883.jpeg" data-component-name="Image2ToDOM"><div class="image2-inset"><picture><source type="image/webp" srcset="https://substackcdn.com/image/fetch/$s_!DIFA!,w_424,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fea20fa17-bddf-4ad1-bcdf-732d033ef687_654x883.jpeg 424w, https://substackcdn.com/image/fetch/$s_!DIFA!,w_848,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fea20fa17-bddf-4ad1-bcdf-732d033ef687_654x883.jpeg 848w, https://substackcdn.com/image/fetch/$s_!DIFA!,w_1272,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fea20fa17-bddf-4ad1-bcdf-732d033ef687_654x883.jpeg 1272w, https://substackcdn.com/image/fetch/$s_!DIFA!,w_1456,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fea20fa17-bddf-4ad1-bcdf-732d033ef687_654x883.jpeg 1456w" sizes="100vw"><img src="https://substackcdn.com/image/fetch/$s_!DIFA!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fea20fa17-bddf-4ad1-bcdf-732d033ef687_654x883.jpeg" width="200" height="270.03058103975536" 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stroke="var(--color-fg-primary)" stroke-linecap="round" stroke-linejoin="round" xmlns="http://www.w3.org/2000/svg"><g><title></title><path d="M2.53001 7.81595C3.49179 4.73911 6.43281 2.5 9.91173 2.5C13.1684 2.5 15.9537 4.46214 17.0852 7.23684L17.6179 8.67647M17.6179 8.67647L18.5002 4.26471M17.6179 8.67647L13.6473 6.91176M17.4995 12.1841C16.5378 15.2609 13.5967 17.5 10.1178 17.5C6.86118 17.5 4.07589 15.5379 2.94432 12.7632L2.41165 11.3235M2.41165 11.3235L1.5293 15.7353M2.41165 11.3235L6.38224 13.0882"></path></g></svg></button><button tabindex="0" type="button" class="pencraft pc-reset pencraft icon-container view-image"><svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-maximize2 lucide-maximize-2"><polyline points="15 3 21 3 21 9"></polyline><polyline points="9 21 3 21 3 15"></polyline><line x1="21" x2="14" y1="3" y2="10"></line><line x1="3" x2="10" y1="21" y2="14"></line></svg></button></div></div></div></a><figcaption class="image-caption"> Ruth Belville at the Royal Greenwich Observatory (Source: Getty Images, originally printed in the Daily Express, March 10, 1908, via Wikimedia Commons)</figcaption></figure></div><pre><code><strong>Roger Bacon:</strong> The 13th-century British polymath who no one listened to when he insisted that the Julian calendar had an error, because of which it no longer aligned with the seasons. A pope who finally showed interest ended up dying before Bacon&#8217;s paperwork and calculations reached him in Rome. The remedy that Bacon had sought only came by in 1582. (In fact, the dating of Easter ultimately played a role in the correction of an imperfect calendar that had dictated the world for over 1,600 years. Had it not been for religion, would the leaders of those times have found it a matter critical enough that their calendar was sliding away against the seasons?)</code></pre><p>These are just a few names; of course scientists and mathematicians during the middle ages played integral roles in solving the biggest questions about our earth&#8217;s motions. Some of them fought with each other for credit and acceptance when they lived, but the truth that matters 400 years later is simple: they all built upon years of human thinking and philosophy, benefited greatly from each other at a busy time for scientific discovery, and together, set the path for future innovations that would shape the world we inhabit.</p><p><em>*I didn&#8217;t, because by then, I had learnt that I could change the time in the device myself whenever I wanted for any experiment.</em></p><p><em>**The reference is to Julius Caesar, his entry into Egypt, and his subsequent and tireless infatuation with Cleopatra.</em></p><p><em>^The reference is to the shift from the Julian to the Gregorian calendar in the UK in 1752, due to which 11 days just vanished from the calendar. (If it happened today, how much rent would you pay your landlord for the affected month?)</em></p><p><em>All information shared here is my interpretation of my reading of the two books, and my own research. I learned about Su Song and Ruth Belville in Orzel&#8217;s book, and Roger Bacon found mention in both books.</em></p>]]></content:encoded></item></channel></rss>