For millennia, humans have had a 0.24219 problem. It’s the extra five hours, 48 minutes and 45 seconds at the end of Earth’s 365-day journey around the Sun. But for as long as we’re on the planet and want to keep track of the date, that tiny number will always cause a big headache.
It’s why today exists: February 29. It was back in 46 BC that astronomers recommended to Julius Caesar that he implement a new calendar which packaged that pesky quarter-day into one convenient lump every four years, tagged onto the shortest month of the year.
But it was an overcorrection – every leap year pushed the calendar 45 minutes ahead of the Earth. By the time Pope Gregory XIII was trying to figure out the date in the 16th Century, that difference added up to 10 days. Not good, considering that the Church relies on the spring equinox to set the date for Easter every year.
So, we have the Gregorian Calendar. Instead of leap years every four years, centennial years which aren’t divisible by 400 keep a regular 365-day cycle. That’s why 2000 was 366 days long, 1900 a day shorter. That keeps our calendar much more aligned with the Earth’s trip around the Sun.
Problem solved. Except, it’s still not perfect. February 29 has led to coding bugs, questions over what to do with the extra business day and wonky interest rates.
According to one academic who wants to scrap our calendar for good, it’s a dated system which costs the US $130bn a year. “For corporate and municipal bonds, the 30/360 rule is used,” explains Steve Hanke, professor of applied economics at Johns Hopkins. “Every month is assumed to be 30 days long, the year 360 days.” Simply put, those receiving interest payments are being short changed by the calendar.
But it’s not just banks. February 29 can catch out businesses too, with the extra day often stretching a traditional 13-week financial quarter into a 14-week one. “They have to insert an extra week every four years,” says Hanke. “It’s quite random, and it fouls up analysts.”
When Apple announced record quarterly revenue in early 2017, it followed a leap year: the additional week inflated profits. It meant a shortfall was sure to follow – the company would be shorn of a week’s revenue, all because of a calendar quirk. “Sales will look like they’re down when they’re not; you get a lot of noise in the financial system,” Hanke adds.
Hanke’s solution? February 30. Alongside Dick Henry, professor of physics and astronomy at Johns Hopkins, Hanke wants to introduce the Hanke-Henry Permanent Calendar (HHPC). A ‘four-quarter 30-30-31 pattern’ would be introduced (meaning two months of 30 days, followed by one of 31, repeated three times) and a 364-day year. Leap days would be scrapped, with the remaining 1.24219 days instead accumulated into a neat ‘leap-week’ package added onto the end of December, every five or six years. “It wouldn’t be a bad deal to get an extra week off at Christmas time,” reasons Hanke.
It’s far from the first time that a new calendar has been mooted. In 1793, post-revolutionary France introduced ten-day weeks. George Eastman, the founder of Kodak, adopted a company-wide 13-month calendar until 1989. The camera pioneer had its extra month, Sol, sandwiched between June and July. And the 364-day World Calendar, popular within the United Nations in the fifties, included a year-end holiday with no day of the week attached called ‘Worldsday’, plus an additional ‘Leapyear Day’ occurring between June 30 and May 1 every four years. Its supporters still aim for worldwide adoption in 2023.
Like the World Calendar, the HHPC is perennial: every date would fall on its same given day forever, so January 1 would always be a Monday. If you were born on a weekend, you’d never have to work on your birthday again. For an economist like Hanke, who also wants to scrap time zones, it’s all a huge time-saver. “Think of the current bureaucratic waste that would be saved. No more calendar committees figuring out when breaks, terms and exams would take place.”
Ruthless efficiency aside, there is still the question of accuracy. Despite its ultra-modern design, the HHPC isn’t as aligned to the solar year as the 450-year-old Gregorian Calendar. That too, however, will be ahead of the Earth’s orbit by one day in around the year 4909. That may seem relatively minuscule, but given that atomic time and leap seconds are used to keep our clocks pinpoint accurate, shouldn’t we have the same robust technology for our calendars?
According to the Royal Astronomical Society’s Dr Robert Massey, it simply isn’t possible. And it all comes back to that 0.24219 problem. “Scientists like numbers which multiply together very easily together. With calendars, the convenient unit of time – the day – doesn’t fit into that other convenient system – the year. And it’s just something we have to live with.”
But one Nasa space scientist claims that there should be more leap days. And it’s all to do with how you define the year. While we follow the solar year (known as the tropical year in astronomy, it’s the time between equinoxes – the complete cycle of seasons), there’s also the fractionally longer anomalistic year: the 365-and-a-bit days from the point of the Earth’s orbit that’s nearest the Sun (known as the perihelion) to the next time it reaches that point. “The annual temperature cycle has been dominated by the anomalistic year,” explains Duncan Steel, who has worked with the US space agency in assessing the threat of asteroid collisions. “And perihelion is slowly drifting forwards in the calendar. If we want to look at climate records accurately, we should really have leap years every four years – plus a super-leap-year of 367 days every century.”
Even if we wanted to follow the tropical year, our calendar could do with a recalculation. “The current system has been devised on a religious basis – climate and seasonal cycles weren’t a concern of the Church in the 16th Century,” Steel says.
It’s thanks to our inaccurate leap year system, which approximates our year as 365.2425 days, that the equinox can fall across three days. That’s despite the Church, and therefore our calendars, defining the equinox as March 21. “Astronomically speaking, it won’t occur on that date until the 22nd Century.”
Steel, who is also author of the book Marking Time, proposes a 33-year cycle with eight leap years in it: after the seventh leap-year, there’s a five-year gap before the next. “That leads to .2424 recurring which is a much more accurate length of the year. That’s why the current system is second-best.”
But he doesn’t go as far as advising that we rip up our calendars and start again. “We have so much invested in the Gregorian Calendar that I can’t see it ever changing. But if you want a more astronomically accurate calendar, we should use it. People use all sorts of calendars already: from the tax year to the football season. They just don’t realise it.”
And what if we just throw our hands in the air and give up trying to solve the leap year problem all together? What if we simply allowed time to march on, 365 days forever? Gradually, the Earth would spin ahead of our calendar, 5 hours, 48 minutes and 45 seconds every year. In our lifetimes, there would be a two-week drift. In around 750 years, the solstices would flip: Christmas would be in summer in the Northern Hemisphere. But it wouldn’t be as dramatic as you might think. “It would creep up through the generations – it wouldn’t bite you in the seat of the pants,” Hanke says. Steel agrees. “It wouldn’t cause havoc. Things already drift slowly, you just don’t notice it.”
For now, we’re stuck with muddling on with February 29. That’s unless Hanke and Henry’s executive order for their new calendar, which they’ve drafted and sent to the White House, gets signed off. It’s their surest bet for worldwide adoption. “The Pope isn’t going to do it like he did in the 16th Century,” explains Hanke. “It’s the President who can put the federal government on any calendar he wants.” Then, we’d have February 30 to deal with. “Donald Trump has the opportunity to be the next Caesar and have a calendar named after him. He might just take it.”
This article was originally published by WIRED UK
