Can We Make a Perfect Calendar?
In short: Why the day, the month and the year never divide neatly into each other, and how people from Meton to Caesar to Pope Gregory XIII, and today's timekeepers, have built careful compromises.
A 1:32 short film in the series “From Fingers to Qubits”, narrated by intellect_voice_01.
Sources used in this film: U.S. Naval Observatory, Astronomical Applications Department (archived via the Wayback Machine), “Introduction to Calendars”; NASA Goddard Space Flight Center (Eclipse Web Site, Fred Espenak), “NASA - Eclipses and the Moon's Orbit”; Royal Museums Greenwich (Royal Observatory Greenwich), “Which years are leap years and can you have leap seconds?”; Royal Museums Greenwich (Royal Observatory), “Which time is it?”; Encyclopaedia Britannica (page labels this Quick Facts text as AI-generated from Britannica articles), “Lunar calendar | Definition & Facts | Britannica”; Perseus Digital Library, Tufts University (Suetonius, Divus Julius 40, Alexander Thomson's English translation, Gebbie & Co., Philadelphia, 1889), “C. Suetonius Tranquillus, Divus Julius, chapter 40”; Encyclopaedia Romana (University of Chicago, penelope.uchicago.edu, James Grout), “The Julian Calendar”; Pontifical Academy of Sciences / Specola Vaticana (Proceedings of the Vatican Conference on the Gregorian Reform of the Calendar, ed. G. V. Coyne, M. A. Hoskin, O. Pedersen), hosted on Internet Archi…, “The Papal Bull of 1582 Promulgating a Reform of the Calendar”; NASA Goddard Space Flight Center (reprint of L. E. Doggett, 'Calendars', from the Explanatory Supplement to the Astronomical Almanac, University Science Books), “Calendars and their History”; National Institute of Standards and Technology (NIST), Physical Measurement Laboratory, Time and Frequency Division, “Leap second and UT1-UTC information | NIST”; NASA Glenn Research Center (grc.nasa.gov), “Calendar Calculations”; NIST (Time and Frequency Division), preprint posted on Preprints.org, “get_pdf.cfm”; Scientific American (article by Elizabeth Gibney, reproduced from Nature magazine), “The Leap Second's Time Is Up: World Votes to Stop Pausing Clocks”.
Sources used in this film
- U.S. Naval Observatory, Astronomical Applications Department (archived via the Wayback Machine) — Introduction to Calendars · View →
- NASA Goddard Space Flight Center (Eclipse Web Site, Fred Espenak) — NASA - Eclipses and the Moon's Orbit · View →
- Royal Museums Greenwich (Royal Observatory Greenwich) — Which years are leap years and can you have leap seconds? · View →
- Royal Museums Greenwich (Royal Observatory) — Which time is it? · View →
- Encyclopaedia Britannica (page labels this Quick Facts text as AI-generated from Britannica articles) — Lunar calendar | Definition & Facts | Britannica · View →
- Perseus Digital Library, Tufts University (Suetonius, Divus Julius 40, Alexander Thomson's English translation, Gebbie & Co., Philadelphia, 1889) — C. Suetonius Tranquillus, Divus Julius, chapter 40 · View →
- Encyclopaedia Romana (University of Chicago, penelope.uchicago.edu, James Grout) — The Julian Calendar · View →
- Pontifical Academy of Sciences / Specola Vaticana (Proceedings of the Vatican Conference on the Gregorian Reform of the Calendar, ed. G. V. Coyne, M. A. Hoskin, O. Pedersen), hosted on Internet Archi… — The Papal Bull of 1582 Promulgating a Reform of the Calendar · View →
- NASA Goddard Space Flight Center (reprint of L. E. Doggett, 'Calendars', from the Explanatory Supplement to the Astronomical Almanac, University Science Books) — Calendars and their History · View →
- National Institute of Standards and Technology (NIST), Physical Measurement Laboratory, Time and Frequency Division — Leap second and UT1-UTC information | NIST · View →
- NASA Glenn Research Center (grc.nasa.gov) — Calendar Calculations · View →
- NIST (Time and Frequency Division), preprint posted on Preprints.org — get_pdf.cfm · View →
- Scientific American (article by Elizabeth Gibney, reproduced from Nature magazine) — The Leap Second's Time Is Up: World Votes to Stop Pausing Clocks · View →
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Sources
- Summary by Intellect · source: U.S. Naval Observatory (Astronomical Applications Department), archived by the Internet Archive Wayback Machine: Introduction to Calendars
- Also: NASA Goddard Space Flight Center (Eclipse Web Site, Fred Espenak): NASA - Eclipses and the Moon's Orbit
- Also: Royal Museums Greenwich: Which years are leap years and can you have leap seconds?
- Also: Royal Museums Greenwich (Royal Observatory): Which time is it?
- Also: Encyclopaedia Britannica (page labels this Quick Facts text as AI-generated from Britannica articles): Lunar calendar | Definition & Facts | Britannica
- Also: Perseus Digital Library, Tufts University (English translation by Alexander Thomson, ed. J. Eugene Reed, Gebbie & Co., P: C. Suetonius Tranquillus, Divus Julius, chapter 40
- Also: Encyclopaedia Romana (University of Chicago, penelope.uchicago.edu, James Grout): The Julian Calendar
- Also: Pontifical Academy of Sciences / Specola Vaticana (Vatican Observatory), Proceedings of the Vatican Conference on the Gr: The Papal Bull of 1582 Promulgating a Reform of the Calendar
- Also: NASA Goddard Space Flight Center (reprinting L. E. Doggett, Explanatory Supplement to the Astronomical Almanac, Universi: Calendars and their History
- Also: Leap second and UT1-UTC information
- Also: NASA Glenn Research Center (grc.nasa.gov): Calendar Calculations
- Also: NIST (Time and Frequency Division), preprint posted on Preprints.org: get_pdf.cfm
- Also: Scientific American (article by Elizabeth Gibney, reproduced from Nature magazine): The Leap Second's Time Is Up: World Votes to Stop Pausing Clocks
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