When does the Millenium really start?

2. Why the Year 2000 is a Leap-Year
Leap-years were introduced into the calendar by Julius Caesar to ensure that the months of the year stay in step with the seasons. This is necessary because the Earth makes one rotation of the Sun in 365.24219, which is clearly not a whole number of days. Adding one extra day every 4 years would exactly correct for a year of length 365.25 days but will over correct for a year of length 365.24219. To make a more exact correction the Gregorian calendar, introduced in 1582, stated that a century year will only be a leap-year if it is divisible without remainder by 400, which is the case for the year 2000. This approximation corresponds to an average year length of 365.2425 days and will amount to a discrepancy of only 1 day after 4000 years. The Gregorian calendar was adopted in Britain in the year 1752 when September 2nd was followed by September 14th.

3. When do the 3rd Millennium and the 21st Century start?
A millennium is an interval of 1000 years and a century is an interval of 100 years. In the Gregorian Calendar, which we use, there is no year zero and the sequence of years near the start runs as follows;

Because there is no year zero, the first year of the calendar ends at the end of the year named 1AD. By a similar argument 100 years will only have elapsed at the end of the year 100AD. Since 2000AD is the 2,000th year of the Christian calendar, it will be the last year of the Second Millennium. So the 3rd Millennium and the 21st Century will begin at the same moment, namely zero hours UTC (commonly known as GMT) on January 1st 2001.

We have received a great deal of e-mail regarding the start of the 21st Century. It is interesting to note that this is not the first time that this controversy has arisen. The Times must have received many letters towards the end of 1799, since its editors felt moved to make the following comments about the beginning of the 19th Century:

"We have uniformly rejected all letters and declined all discussion upon the question of when the present century ends, as it is one of the most absurd that can engage the public attention, and we are astonished to find it has been the subject of so much dispute, since it appears plain. The present century will not terminate till January 1, 1801, unless it can be made out that 99 are 100... It is a silly, childish discussion, and only exposes the want of brains of those who maintain a contrary opinion to that we have stated"

The Times, 26 December 1799

The idea of naming years BC was introduced by Bede in the 8th century. Naming years in the Christian Era came into common use in ecclesiastical circles in the Middle Ages but was not adopted for civil use until later.

More information about Dionysius and the medieval calendar can be found at the US Naval Observatory web site.

3.2 Other Calendars and Eras in use
Apart from the Christian calendar, there are about 40 other calendars in use throughout the world. A few of them are listed, showing their years on 1 January 2000; Byzantine 7508, Chinese 4636, Indian (Saka) 1921, Islamic (Hegira) 1420, Jewish(A.M.) 5760. The date on which the year changes is different for each calendar.

4. Why the Millennium starts at zero hours at Greenwich.
The ``INTERNATIONAL CONFERENCE HELD AT WASHINGTON FOR THE PURPOSE OF FIXING A PRIME MERIDIAN AND A UNIVERSAL DAY'' in October 1884, resolved to adopt the meridian at Greenwich as the prime meridian for``all the world'' and the time and day at the Greenwich meridian as the universal time and day for ``all the world''. In practice, this time, referred to now more correctly as UTC, is identical to what is widely known as GMT and forms the basis for our claim that the Millennium will start at zero hours Greenwich time. The same conference stated that the``universal day shall not interfere with the use of local or other standard time where desirable.'' Put simply this means that in Sydney they are not going to wait until 10 next morning before celebrating the New Year.

4.1 Where is the Greenwich Meridian ?
The famous brass strip seen at the Old Royal Observatory Greenwich, London, marks the Airy meridian referred to in the 1884 treaty. However the meridian to which the UK Ordnance Survey is tied lies 5.79m to the west while the GPS satellite meridian lies 102.51m to the east. (See The longitude of Greenwich )

5. The International Date Line.
The international dateline is an imaginary line of longitude located about 180 degrees east (or west) of the Greenwich meridian. This is the line across which the date changes by one day. To understand this imagine it is 3pm GMT on January 3 at Greenwich. 15 degrees east of Greenwich the local time will be 4pm, one hour ahead. In Japan, 135 degrees east it will be 9 hours ahead and the local time will be midnight January 3/4, while in E Australia, 150 degrees east it will be 1am on January 4th. In New Zealand, close to the International Date Line, the local time is 3am on January 4th. Now let us return to Greenwich and imagine travelling west towards America. For every 15 degrees we travel the local time is an hour behind. For example the local time in California is 7am on January 3. As we continue west towards the International Date Line the local time falls further behind, until at the date line the time is 3am on January 3. This illustrates two things, firstly that there is no change of local time crossing over the date line although the date changes by one day and secondly, the obvious value in adopting a standard time and day that can be used to date events anywhere in the world without ambiguity.

5.1 Legal Status of the International Date Line and Kiribati.
Despite its name, the International Date Line has no international status and was not defined by the 1884 convention or any other treaty. This means that countries close to the Date Line are free to choose which date they will observe.

On 23 December 1994 The Republic of Kiribati announced that;`` with effect from 1 January 1995 all islands in the Line and Phoenix Groups within the Republic of Kiribati shall be on the same date of the islands in the Gilberts Group within the Republic while their time are maintained to what they are as at present''. This perfectly reasonable decision from an administrative point of view, puts a large eastward bulge in the International Date Line. It also places Caroline Island, since renamed Millennium Island, as a leading contender to see the first sunrise of the millennium.

5.2 Fiji and Longitude 180 degrees.
The Islands of Vanua Levu, Rambi and Taveuni, all part of Fiji, have the distinction of being the only islands crossed by the 180 degree line of longitude in the Pacific. The other places where the 180 degree longitude crosses land are, Wrangel Island (Vrangelya Ostrov, 71 degrees north), far NE Russia and Antarctica. The highest peak on the Island of Taveuni, called Uluinggalau or Uli i Ngalu, lies just 200 meters west of the 180 longitude! Although not a leading contender to see the first sunrise this is clearly a place of great geographical interest. The Sun will rise at the point where the 180 longitude crosses the coast of Taveuni, 9km to the south of Uluinggalau, six minutes after it is seen to rise from the top of Uluinggalau.

6. Where to see the first Sunrise of the New Millennium.

6.2 The View From Antarctica.
At the South Pole the Sun will have risen at the previous equinox, on 22 September 2000, and will not set until the following equinox, on 20 Mar 2001. Does this make the South Pole the first place to see the first Sunrise of the new Millennium on 22 September 2000 or only the last place to see the last Sunset of the old Millennium?

The US Naval Observatory has pointed out that the Sun will set and then rise in Antarctica, at longitude 135 degrees East on the headland between the Dibble Glacier and Victor Bay, at 15:08 UT on 1 Jan 2000. However, it will only have been below the horizon for less than half an hour that night!

6.3 The Local Time View. It is common cause that the start of the New Year is celebrated by people around the world according to their own local times and that most people will celebrate the start of the year 2000 not 2001. In the table below we list the times of sunrise for various places at the start of the year 2000. In practice the difference in times between 2000 and 2001 is negligible.

The places in the above table are listed in order of the time of sunrise. The times in column 5 are given in UTC which is the time at Greenwich. The last column gives the local standard time. We have attempted to take into account local daylight savings time wherever possible. The precise time of sunrise depends on the height of the horizon and the observer. The horizon is assumed to be at sea-level and the heights in column 4 refer to the observer. The entry for Antipodes Island refers to Mount Galloway and for Pitt Island, Mount Hapeka.

6.3 Will the Sun rise at the time stated?
The calculation of the time of sunrise depends on using a model for the way the Earth's atmosphere bends light. For example when the entire disk is seen to be above the horizon the real Sun is still just below the horizon. An average model of the atmosphere is used so that the actual time of sunrise can vary by at least 1 minute, depending on actual conditions.

6.4 Time and place of first Sunrise in the UK on 1 Jan 2000. South Foreland close to Dover, will be the first place in the UK to see the Sun rise on 1 January 2000 at 07hrs 58mins.

6.5 The last Sunset and the first Sunrise. Anyone that accepts that the first sunrise of the New Millennium will be seen from Caroline Island has the possibility of flying 1500 miles west to Samoa and seeing the last sunset of the old Millennium, 14 hours and 14 minutes later.