Is there a better calendar we could use or invent? Evie Sutton, Manchester Send new questions to nq@theguardian.com. Readers reply One with a small chocolate behind the little door every day of the year please. SignificantOther Composers/artists La Monte Young and Marian Zazeela live in “extended time”. I believe each “day” for them is 35 hours long, with 8 hours for sleep; if one wants to interview or meet them, one has to fit in to this extended day; for example arriving at 3am to find them having lunch. Reedist There is a fixed ratio of Earth rotations to orbits of the sun. So whatever calendar we use would have 365¼ days in a year. Division into some convenient blocks like weeks and months falls down on there not being convenient factors. If we were starting again, then 366 might be an approximation to start with. Weeks of six days and months of 61 could work – other than one arbitrary “leap” day skipped most years. It would still leave unaligned weeks each month, unless we decided to have the first week of every new month being “new Monday” to “new Saturday”. That would involve “intercalary” days (“new Sunday”?) inserted at the end of six (or five) of the 61 (or 60) day months. We could of course allow for more intercalary days, something like the calendar the Romans used before Julius Caesar, where they had most years of 355 days, but some of 377 or 378 with an extra short month. The answer to the question, then, is whatever calendar you choose has some arbitrary fudging. Producing a worldwide consensus on an alternative is way too large a hurdle for minimal advantage, so extremely unlikely to happen. leadballoon There’s no intrinsic need to tie a calendar to solar, terrestrial or lunar cycles. It made sense to do that when those were among your most readily available periodic observables. Dorkalicious How about 10 months of 36 days each (four weeks of nine days with three- or four-day weekends), with the other five or six leftover days as a very long bank holiday at the end of each year. OhReallyFFS If you mean “accurate”, then the Persian Hijri calendar used in Iran is far better than the Gregorian calendar. It starts and ends a year on the actual observation of the spring (vernal) equinox. Years are either 365 or 366 days long with 12 months. The first six months are each 31 days long; months 7 to 11 are 30 days each, with the final month being either 30 or 31 days long. Unlike the Gregorian calendar, leap years are not regularly distributed according to a simple mathematical rule, but are instead inserted based on astronomical observations. The result is that the calendar only accumulates a one-day error in every 110,000 years compared with the one day every 3,236 years in the Gregorian calendar. Of course all calendars assume the Earth’s orbit around the sun and the length of the day are constant – which they aren’t. MikeRichards Arguably, that is not better than the Gregorian calendar. For the Gregorian calendar, (as you said) there is a simple formula that can be used in computer systems, including for future dates. For the Hijri calendar, it would be not just difficult, but impossible to work accurately with future dates where they depend on observations which have not yet taken place. In other words, a larger, predictable amount of “wrong” is better than “less wrong but unpredictable”. I worked in IT for 35 years and I have no idea how you would go about handling the future date case in the Hijri calendar, but I doubt that there is any very satisfactory method. mikecee A printer I once knew had printed his own calendar with two Fridays in every week. When I spotted it on his office wall he explained that it was the only way he had a cat in hell’s chance of fitting in all the jobs that customers wanted before the weekend. Nowadays, though, I don’t think calendars of any kind will survive for much longer – anyone can see that their days are numbered. ThereisnoOwl In June 1972, Isaac Asimov wrote an essay in the Magazine of Fantasy & Science Fiction that described a very easy to understand calendar system. Basically, there are four periods of 90 days plus a few holidays in between the 90-day periods to make the year come out to the right number of days. Rick Bergman Much of modern computing already does: it’s called Unix time, which began at midnight on 1 Jan 1970 [UTC] and increments in seconds. The switchover likely wouldn’t be all that hard in practice as it’s so well embedded today, albeit not too many people would immediately recognise that. It would lead to significant simplification in a connected world, as well as being easily distributed using protocols designed to do so while maintaining accuracy. As things stand, the clock can accommodate many multiples of the current age of the universe – but hold that thought, because in a few years (2038) there’s going to be a spot of trouble when older 32-bit technology can’t handle the latest standard (64-bit Unix time) runs into a bit of a problem at the end of the “first Unix epoch”. Dorkalicious I quite liked the idea of the Shire calendar, as described in Tolkien’s works. There were 12 30-day months, with an additional day at the end of the year and one at the beginning. These were at midwinter and called the Yule days. At midsummer, there were three additional days (four in leap years) called Lithe days. Mid-lithe day and the additional leap-year day were not given weekday names, and were kept out of the cycle of seven-day weeks. In this way the year always started with a Sterday (Saturday). Yule actually lasted six days, as the last two days of Foreyule (the last month of the year) and the first two days of Afteryule (the first month of the year) also counted as part of the Yule festival. Given the regular cycle of 30-day months, the adoption of a six-day weeks would make sense (abandon weekday names for all of the Yule and Lithe days), and give us the opportunity to ditch Mondays, because in common with most people, I don’t like Mondays. HiFiAlan We need it to be decimal, based on days. No hours, just decidays centidays and millidays and so on. No weeks months or years, just dekadays, hectodays, kilodays. No weekends, just a rolling three days off every dekaday, life expectancy about 25 kilodays. No annual reports, kiloday reports, which would encourage longer-term thinking, kiloday election cycles. We would get 2.74 summers every kiloday, and the same number of winters, but we would escape the tyranny of religious festivals and suchlike. Fewer birthday presents to buy. Easier payroll software. Let’s backdate it to 2000 so 01/01/2000 is day one of the Modern Decimal Era (MDE). Meet you in the coffee shop at 8072.052 MDE (half past 12, Sunday 6 Feb in old time), but in everyday speak you would probably say “see you at 72.05” unless you were planning well ahead. RichardCC A non-leap year consists of 52 weeks + 1 day. Converting to days: one year = 52x7 + 1 = 13x4x7 + 1 = 13x28 + 1 If we are ever able to overcome our superstitious attachment to number 12 and revulsion to 13, we could have a nifty 14-month calendar, with 13 months of equal length, 28 days, and a special month of length one day, the latter which will double in leap years. This way we don’t need to worry about those irritatingly irregularly alternating 30/31-day months, where July/August and December/January all have 31 days even though they are pairwise adjacent. Where’s the logic in that? When the superintelligent AI takes over the world as the universal philosopher-king in 2046, I might work up the courage to suggest this calendar design to its royal highness. trp981 Weeks are five days, with a working week of three days out of five. Months are six of these weeks. The year starts at the winter solstice. There are additional days at the equinoxes and solstices to bring the total to 365 (with leap years having six of these extra days). These additional days are holidays and aren’t part of the main weeks/months (eg the last day of the sixth month and 36th week is followed by the summer solstice holiday, which is then followed by the first day of the seventh month and 37th week). The system is natural and secular. It has no need to remember different lengths of months, and gets rid of financial difficulties that can happen for those with weekly wages and monthly bills. It makes a compromise in the proportion of time spent in the working week between what we have now and proposals sometimes made for a four-day week. Tom Lloyd