numbers a giant leap in time

Share
Related Topics
Today is the 29th of February. Why? Well, it's partly Julius Caesar's fault, but is mainly to do with the earth's orbit round the sun. The trouble is that the earth takes 365 days, 5 hours, 48 minutes, 45.51 seconds to complete its trip, which makes it slightly late for its annual appointment after a 365-day year.

In four years, the delay adds up to 23 hours, 15 minutes and 2.04 seconds, so adding a leap day now makes it start the next year some 45 minutes early. After 128 years, those 32 batches of 45 minutes each will have added up to a full day.

Julius Caesar decreed, in 45BC, that every fourth February should have an extra day in February. Unfortunately, as he forgot the centuries, the world gradually edged ahead of the calendar. Between the Council of Nicaea in AD 325 and an edict of Pope Gregory XIII in 1582, the date of the spring equinox (important for calculating Easter) slipped from 21 March to 11 March. On the advice of his astronomers, Pope Gregory solved the problem by ordaining that 5 October 1582 should be called 15 October, and thenceforth no century year would have a leap day, unless the century was itself divisible by four. So 1600 was a leap year, but 1700, 1800 and 1900 were not. And 2000 will be. Most of Europe adopted the Gregorian calendar in 1582 or 1583. Britain took until 1752 to make the change, by which time it was 11 days adrift and had to lose all the days between 3 and 13 September.

The Gregorian calendar thus operates on a 400-year cycle, with a total of 97 leap days. That gives 146,097 days every 400 years, an average 365.2425 days per year, or 365 days, 5 hours, 49 minutes and 12 seconds.

So we are still slipping by about 27 seconds a year. Which means we may need another leap day adjustment in some 3,000 years' time. Despite the accuracy of the Gregorian calendar, however, one cannot help feeling sorry for anyone born 100 years ago today, who would not have had a true birthday until they were eight.

None of which explains the custom that women may propose marriage on 29 February. That has nothing to do with Julius Caesar or Pope Gregory but is, according to Brewer's Dictionary of Phrase and Fable, the result of delicate negotiation by St Patrick.

He was, Brewer claims, walking along the shores of Lough Neagh, when accosted by a tearful St Bridget. Her nuns, she explained, had mutinied over the right to propose marriage. When St Patrick offered to allow them to do so every seven years, St Bridget threw her arms round his neck and said: "Arrah, Patrick, jewel, I daurn't go back to the girls wid such a proposal. Make it one year in four." St Patrick replied: "Bridget, acushla, squeeze me that way agin, an' I'll give ye leap-year, the longest of the lot."

Bridget then proposed to Patrick, who solved the problem by giving her a kiss and a silk gown instead. Since when, it is said, any woman whose leap year proposal is turned down may claim a silk gown.

The usual numbers feature by The Anaesthetist will return next week.

React Now

iJobs Job Widget
iJobs General

History Teacher

£110 - £120 per day: Randstad Education Chelmsford: We are seeking a teacher o...

IT Teacher

£110 - £120 per day: Randstad Education Chelmsford: We are seeking a suitably ...

Legal Cashier - Oxford

Very Competitive: Austen Lloyd: Legal Cashier - Oxford We have an excellent ...

Legal Cashier - Oxford

Very Competitive: Austen Lloyd: Legal Cashier - Oxford We have an excellent ...

Day In a Page

Read Next
 

The daily catch-up: Joe on Vlad, banks of the Jordan and Blair's radicalism

John Rentoul
 

Believe me, I said, there’s nothing rural about this urban borough’s attempt at a country fair

John Walsh
Some are reformed drug addicts. Some are single mums. All are on benefits. But now these so-called 'scroungers’ are fighting back

The 'scroungers’ fight back

The welfare claimants battling to alter stereotypes
Amazing video shows Nasa 'flame extinguishment experiment' in action

Fireballs in space

Amazing video shows Nasa's 'flame extinguishment experiment' in action
A Bible for billionaires

A Bible for billionaires

Find out why America's richest men are reading John Brookes
Paranoid parenting is on the rise - and our children are suffering because of it

Paranoid parenting is on the rise

And our children are suffering because of it
For sale: Island where the Magna Carta was sealed

Magna Carta Island goes on sale

Yours for a cool £4m
Phone hacking scandal special report: The slide into crime at the 'News of the World'

The hacker's tale: the slide into crime at the 'News of the World'

Glenn Mulcaire was jailed for six months for intercepting phone messages. James Hanning tells his story in a new book. This is an extract
We flinch, but there are degrees of paedophilia

We flinch, but there are degrees of paedophilia

Child abusers are not all the same, yet the idea of treating them differently in relation to the severity of their crimes has somehow become controversial
The truth about conspiracy theories is that some require considering

The truth about conspiracy theories is that some require considering

For instance, did Isis kill the Israeli teenagers to trigger a war, asks Patrick Cockburn
Alistair Carmichael: 'The UK as a whole is greater than the sum of its parts'

Alistair Carmichael: 'The UK as a whole is greater than the sum of its parts'

Meet the man who doesn't want to go down in history as the country's last Scottish Secretary
Legoland Windsor's master model-makers reveal the tricks of their trade (including how to stop the kids wrecking your Eiffel Tower)

Meet the people who play with Lego for a living

They are the master builders: Lego's crack team of model-makers, who have just glued down the last of 650,000 bricks as they recreate Paris in Windsor. Susie Mesure goes behind the scenes
The 20 best days out for the summer holidays: From Spitfires to summer ferry sailings

20 best days out for the summer holidays

From summer ferry sailings in Tyne and Wear and adventure days at Bear Grylls Survival Academy to Spitfires at the Imperial War Museum Duxford and bog-snorkelling at the World Alternative Games...
Open-air theatres: If all the world is a stage, then everyone gets in on the act

All the wood’s a stage

Open-air productions are the cue for better box-office receipts, new audiences, more interesting artistic challenges – and a picnic
Rand Paul is a Republican with an eye on the world

Rupert Cornwell: A Republican with an eye on the world

Rand Paul is laying out his presidential stall by taking on his party's disastrous record on foreign policy
Self-preservation society: Pickles are moving from the side of your plate to become the star dish

Self-preservation society

Pickles are moving from the side of your plate to become the star dish
Generation gap opens a career sinkhole

Britons live ever longer, but still society persists in glorifying youth

We are living longer but considered 'past it' younger, the reshuffle suggests. There may be trouble ahead, says DJ Taylor