What day of the week is Jan 1st 1,000,000AD ?

Discussion in 'Computer Support' started by Trevor Smith, Nov 4, 2003.

  1. Trevor Smith

    Ralph Mann Guest

    Trent C said:
    Oh bugger.
    Back to the drawing board ;-)

    I'm wondering if those sites that show the day as Friday instead of Saturday
    have based their calculations on the first day being Sunday instead of Monday.
    People do tend to think that Sunday is the first day of the week, as can be
    shown on calendars.
    Ralph Mann, Nov 5, 2003
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  2. Trevor Smith

    Trent C Guest

    Let's not give up completely. Look again at my calculations - we start with
    1,000,000 years and subtract 2,000 because we're starting from 2,000 to give
    us a base line (and, incidentally, so we're staying in the Gregorian
    calendar) [998,000]

    Then we multiply by 365 [364,270,000] and add a full complement - less
    2,000 - of an additional 249,500 days - that's 250,000 less 500 for the
    2,000 years we're skipping - to account for the 1 in 4 leap years
    [364,020,500] and for god's sake make sure you're following this with your
    own calculator!

    Then we readjust for leap century years - only 1 in 4 century years is also
    a leap year, so we must add back the 3 in 4 century years that weren't leap
    years. This is where I'm struggling with fatigue - it's been a long day in
    the office. Am I right in thinking that this calculation is
    ((998,000/100)x3), giving us 29,940? [364,050,440]

    Then we just divide by 7 [52,007,205.71], which now suggests Wednesday.

    Any thoughts?
    Trent C, Nov 5, 2003
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  3. Trevor Smith

    Ralph Mann Guest

    Trent C said:
    You forgot to add 1 for the fact that 2000 is a leap year ;-)
    Why are you deducting anything when you are already not including the first 1999
    (not 2000) years in your count anyway?
    No, you are skipping the first 1999 years.
    You are using 1st Jan 2000 as a starting point.
    Ralph Mann, Nov 5, 2003
  4. Trevor Smith

    rednose Guest

    Do you mean Monday December 31st 999,999. ?

    rednose, Nov 5, 2003
  5. Trevor Smith

    Trent C Guest

    I don't think we need to add one for the year 2000 being a leap year, as it
    all balances out by the end of 999,999.
    I'm only deducting the 500 from my calculation of the total number of
    additional leap days in 1,000,000 years - 1,000,000 years, 1 leap year in 4
    is 250,000 days, less 500 for the 2,000 years we're skipping in the
    No, my calculation is designed to get from January 1st 2000 to December
    31st, 999,999, so I am counting from the beginning of 2,000 to the end of
    999,999: 998,000 years.
    Trent C, Nov 5, 2003
  6. Trevor Smith

    Ralph Mann Guest

    Trent C said:
    Ofcourse you do, as it *is* a leap year, and *does* contain 366 days.
    Don't you have to deduct days seeing as the centuries non-divisible by 400
    *don't* have 366 days?
    Ralph Mann, Nov 5, 2003
  7. Trevor Smith

    Trent C Guest

    I take your point, Ralph, but surely this is dealt with at the end of the
    998,000 years, as the last 3 years aren't leap years. If the starting point
    was a leap year out of sequence, I'd agree with you.
    Yes, we do that later on. I separated the processes for extra visibility.
    By the way, I emailed the boffins at the National Physical Laboratory in
    Rugby with this query. They run one of the atomic clocks and hopefully
    it'll tickle their intellectual interest. I'll post back to this thread if
    I get a response, but it would be great if we could get a resolution by
    Trent C, Nov 5, 2003
  8. Trevor Smith

    Ralph Mann Guest

    Trent C said:
    I have to concede on this point as the total number of years is wholly divisible
    by 4. ;-)
    Don't forget that you are going up to 999,999 and not 1,000,000, so you need to
    drop 1.
    That will be interesting, did you ask what weekday they start off with on 1st
    Jan 0001 ?
    Ralph Mann, Nov 5, 2003
  9. Trevor Smith

    Trent C Guest

    Yes and no. I'm going from the beginning of 2000 to the end of 999,999 (see
    my earlier comment below)
    Don't even go there!
    Trent C, Nov 5, 2003
  10. Trevor Smith

    Ralph Mann Guest

    Trent C said:

    Why not?
    You will need confirmation of whether Sunday or Monday is officially the first
    day of the week to base the decimal calculation on.
    Ralph Mann, Nov 5, 2003
  11. Trevor Smith

    Trent C Guest

    'cos we're starting at January 1st, 2000, not 0001. That way we don't have
    to account for the 18th century move to the Gregorian calendar.
    Trent C, Nov 5, 2003
  12. Trevor Smith

    Bri. Guest

    The year has commeced in January, since 1752 (UK) or 1582 (Europe),
    depending on your location.
    Bri., Nov 5, 2003
  13. Trevor Smith

    Ralph Mann Guest

    Bri. said:
    So what do these sites use to calculate dates ranging from 5000+BC to 10
    gazillion AD ?
    I doubt they use a mixture of calendars and just use one formula to calculate
    what the date "would have been" based on todays calendar.
    The same goes for what the date "might be" by 1million AD, as no-one knows what
    system will/may replace the present system.
    Ralph Mann, Nov 5, 2003
  14. Trevor Smith

    Trent C Guest

    I agree completely. That's why I think it's best to start form a known
    point, like 01/01/2000 - a Saturday.
    Trent C, Nov 5, 2003
  15. Trevor Smith

    Ralph Mann Guest

    Trent C said:
    Actually, I think it would be simpler to forget about the first 2000 years
    anyway and start from 1st Jan 2001.
    Most of them contain bad memories for me anyway ;-)
    Ralph Mann, Nov 5, 2003
  16. Trevor Smith

    Trevor Smith Guest

    I went here... http://www.geocities.com/eu84/frtop_files/calendar.htm
    Thanks for the link. I would agree with Saturday for the Gregorian calendar,
    because in 400 years there are 365*400+97 days or 146,097 days. As this
    figure divides *exactly* by 7, it follows that as January 1st 2000 was a
    Saturday, so will be January 1st 2400, January 1st 2800, January 1st 3200
    .... , January 1st 1,000,000.

    So much for the Gregorian calendar. I have seen the tropical year (period
    for the repetition of the seasons) given as 365.242190 days, whereas the
    Gregorian calendar approximates a year as 365.2425. The difference between
    these two numbers, 0.00031 amounts to an error of around 310 days over the
    next million years! In other words Jan 1st will be mid-summer (for the
    northern hemisphere) around 500,000AD (Gregorian) and would be heading back
    towards mid winter by 1,000,000AD! Making a lot of assumptions, this
    probably would be prevented by new leap year rules, which would affect the
    day of week for 01/01/1,000,000.

    It gets worse. I have also seen that the Earth is slowing down by 0.005
    seconds per year, per year. Over a million years -
    0.005+0.010+0.015+0.020+...+4999.995+5000.000 seconds or about 79 years.
    ASSUMING the rate of slowdown is constant. So now I'm not even certain what
    YEAR it will be in 1,000,000 AD.

    Trevor Smith, Nov 5, 2003
  17. Trevor Smith

    Just Taylor Guest

    I've just decided to use the ATM, it doesn't matter if the bank is open.
    Just Taylor, Nov 5, 2003
  18. Trevor Smith

    Ed Guest

    .... and we thought we had troubles with Y2K.

    (excellent thread guys, keep it up)
    Ed, Nov 5, 2003
  19. Trevor Smith

    Steve Guest

    Except that on 1st jan 1,000,000 AD all the ATM's will crash with the year
    1M bug.
    Steve, Nov 5, 2003
  20. Trevor Smith

    Ralph Mann Guest

    Trevor Smith said:
    I don't know where you get that reasoning from, just because it is divisible by
    400, doesn't mean it is divisible by 7.
    Ralph Mann, Nov 5, 2003
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