Welcome to the NavList Message Boards.


A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

Compose Your Message

Add Images & Files
    Re: no leap second coming in December
    From: Frank Reed CT
    Date: 2004 Jul 29, 13:53 EDT
    Casey M wrote:
    "I too find this rather interesting.  I read recently in the NY Times about some research describing that the magnetic field flips every now and then, between every 1,000 to 28,000 years and that it may be getting ready to flip in the next one or two thousand years."

    Although there has been some casual speculation that the Earth's magnetic field might be starting into a polarity flip, there's nothing to it but speculation. Most geophysicists dismiss the possibility (but agree that there is a low probability that it could occur soon). That time period you're refering to is the estimated time to COMPLETE a polarity reversal, by the way. The time between reversals ranges from a few thousand to hundreds of thousands of years, and it's not periodic in any simple way.

    One of the FAQs on the USGS geomagnetism site discusses this issue. The faq page is here:

    And for some maps of the Earth's changing magnetic field, visit here:

    "If you do a web search on "magnetic flip" or similar, you'll find a lot of info.  It would be interesting to find a reference stating that the core flow changes could also be affecting the spin rate of the earth."

    Though it's possible in principle, there is no observed correlation between spin rate changes and magnetic field changes (at this time). They are essentially independent phenomena.

    Frank R
    [ ] Mystic, Connecticut
    [X] Chicago, Illinois
    Browse Files

    Drop Files


    What is NavList?

    Join NavList

    (please, no nicknames or handles)
    Do you want to receive all group messages by email?
    Yes No

    You can also join by posting. Your first on-topic post automatically makes you a member.

    Posting Code

    Enter the email address associated with your NavList messages. Your posting code will be emailed to you immediately.

    Email Settings

    Posting Code:

    Custom Index

    Start date: (yyyymm dd)
    End date: (yyyymm dd)