It is well established custom and ritual to wish those close to us a happy new year and to celebrate the end of the old year and to make new resolutions for the coming year. All civilizations and all cultures have their celebrations and, as each country has its own official time, a carefully organised flight around the world would enable a curious traveller to see the new year in and hear midnight strike 24 times in different places, as that is traditional way of passing over from 31st December to 1st January. Each year celebrates a clearly established cosmic event, the completion of a new revolution of the earth around the sun. But that is just the theory. In reality it is far more complex. We are not in a stadium where the starting and finishing lines are clearly and materially marked, and, owing to problems of reference points, nobody really has the same calendar. Let consider matters from the point of view of an astronomer to begin with, and see how much time passes for the earth to return to an imaginary line linking to the sun to another reference star. This would be the sidereal year, which is 365 days, 6 hours, 9 minutes and 10 seconds long. That would be perfect if the orbit was circular, which is obviously not the case. Let us now examine the situation from the point of view of a mathematician. The distance separating the earth from the sun is approximately 147 million kilometre in January and 152 million kilometres in July. The anomalistic year, which measures the time it takes the earth to return to the point nearest to the sun, is then 365 days, 13 minutes, and 53 seconds long. Finally, let us see the problem from geographers point of view. He would observe the return of Phoebus, influenced by the cycle of the seasons, back to the same point in Zodiac belt. This is the tropical year and lasts 365 days, 5 hours, 25 minutes and 46 seconds. There are thus three methods of calculation, producing three different results, and all of them are valid. It is an interesting problem, but a little embarrassing when it comes to choosing. Moreover, this hesitation marks the history of calendars. The Romans had their calendar begin on 1st March. The Christians chose 25th December (the date established in 337, by Pope Julius I as the day of Christs birth), or the 25th March which is the day of the Annunciation to Mary. The Muslims prefer to begin with the day on which Prophet Mohammed left Mecca to Madina. In 1564, the king of France Charles IX fixed the beginning of the official year at 1st January. The revolutionaries, which introduced the Republican calendar, chose the autumn equinox as the beginning of the year. A second dilemma faced the many creators of calendars. The Scientific year (whichever one it is) does not include a number of complete days. Indeed, the earths rotation (on its own axis) is independent from its revolution (its movement around the sun). Hence it is impossible to imagine an unchanging succession of years made up of on the same number of days. A similar problem arises for those who wanted to base their calculations on the phases of the moon. So what could be done? The Israel calendar takes into account both sun and the moon. It alternates years which can have twelve or thirteen months, that is to say from 353 to 385 days, so as to create an average month equivalent to a lunatic and an average year close to tropical year. The Muslim year, however is fundamentally lunar. Its average year has 354.37 days. A cycle of thirty years thus contains 19 years having 354 days and 11 years having 355 days. The Gregorian calendar which is the one used in most western countries, is strictly solar and was created in such a way as to ensure the closest concordance, over a long period, between official years and tropical years. That is why; in 1582 Pope Gregory XIII reformed the ratio of the leap years to ordinary years and the difference (today numbering 13 days) between this new calendar and the Julian system, which is in use in Orthodox countries, appeared. When counting the year, the most widespread calendars begins Year One on the first of January following the presumed date of the birth of Christ, while knowing full well that the margin of error for determining that year is estimated at ±4 years. The year before is considered as year One before Christ. Although this system may satisfy most people, it does not meet with the approval of scientists for whom it is not possible to pass from -1 to +1. Already in 1770, Cassini advocated that -1 should become 0 and that hence 2 should become -1. As the scientific journalist Albert dardizers finally came along to put their word in. Ducrocg points out the standardisers finally came along to put their word in. the International Standards Organisation proposed a ISO calendar to establish the days, months and years. So if the first week of the year began in the week which had the first Thursday in January, for the ISO, there were 52 weeks. However, there will be 53 weeks a year if the year begins on a Thursday, or on a Wednesday, in the case of leap year. So if youre celebrating New Year, really with year are you celebrating????????????!!!!!!!!!!!!!!