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    Re: Is the date ever the same globally?
    From: Navastro
    Date: 2004 Oct 15, 12:47 +0200

    Hello,
    I think that it is correct. I include a figure that will help (I hope)
    to see it. The figure shows the situation as seen from above the north
    celestial pole.
    
    Best regards,
    Luis
    
    On Fri, 2004-10-15 at 11:37, Jim Thompson wrote:
    > I need to check my understanding of this with the list.  Is this line from a
    > book correct:
    > "...at the instant of GMT 1200, the date is the same all over the world"?  I
    > think it is wrong.
    >
    > 1. On
    > http://jimthompson.net/boating/CelestialNav/DatesTimeDiagrams.htm
    > I tried last year to prove that statement to myself, but was unable to do
    > so.  See
    > http://jimthompson.net/boating/CelestialNav/TimeDateConversionTable.htm.
    > Note in that table (I made up this table, so I hope it is right) that when
    > it is 1200 at Greenwich on day 10 (say), it is is 2400 the previous day in
    > Time Zone Y (ZD -12), and so it can never be the same date at every place on
    > the planet at once.  The instant it turns to 1200 at Greenwich, the time in
    > M is 2400 on the same day, but the time Y is 2400 on the previous day
    > Right?
    >
    > 2. There are 25 time zones, not 24, right?  The way I see it, that is
    > because the 15d span of longitude around the IDL is divided into Y (ZD -12)
    > and M (ZD +12).  Although time is always the same in those two "half zones",
    > date is always different.  Am I right?  Or is that just splitting hairs to
    > say that there are 25 time zones, since the time in Y and M is always the
    > same, even though the date is different?
    >
    > (I am working on a CN PowerPoint presentation for teaching, so need to pin
    > this down.)
    >
    > Jim Thompson
    > jim2@jimthompson.net
    > www.jimthompson.net
    > Outgoing mail scanned by Norton Antivirus
    > -----------------------------------------
    >
    
    
    
    

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