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Deciphering Email Dates
The email date field specifies the date and time the email
was sent, offset from Greenwich
Mean Time, similar to the following:
Wed, 17 Jan 2000 16:40:10 -0500
This time is specified in 24-hour format, so that 16:40 is
the same as 4:40 PM. The number
at the end, "-0500", is an offset added to each email by the originating
email server to indicate the number of hours difference between local time
and the world baseline Greenwich Mean Time (GMT) in Greenwich, England. Therefore,
an email with an offset of -0500 is five time zones west of Greenwich, and an
email with an offset
of +0400 is four time zones east of Greenwich. GMT is also sometimes referred
to as Universal Time Coordination (UTC), and sometimes as Zulu time, and has
been based on atomic clocks since 1986.
The GMT offset can be used with a little calculation to compare the times of
emails sent from different places around the world. This can be useful when reviewing
late breaking news stories, or following newsgroup postings, to see which was sent first.
Remember that on the Internet that a person may be physically in one time zone
and logging into an email server in a different time zone, so their email
will be labeled with a time and GMT offset that reflects their email server's location, which
may not necessarily be their own location.