Welcome to the NavList Message Boards.

NavList:

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

Compose Your Message

Message:αβγ
Message:abc
Add Images & Files
    or...
       
    Reply
    Re: FOGs
    From: Frank Reed
    Date: 2008 Jan 30, 19:39 -0500

    George, you wrote:
    > However, the link to the Gravity B experiment came from Paul Hirose, not
    > Frank. And it leads to a further question-
    >
    > That article, http://einstein.stanford.edu/sitemap.html  , was written in
    > the future tense, describing a proposed experiment which was intended to
    > launch in 2003, and last for two years. So by now it should have
    > been-and-gone. Can anyone tell us whether it actually happened, an if so,
    > what the results were?
    
    Yes, that was Paul.  :-)
    
    I have been following the evolution of the plans for this mission since the
    1980s (the original funding for research on this project goes back to the
    early 1960s). The mission ran from launch in April 2004 up until the
    evaporation of the last liquid helium in September 2005. As for the results,
    the principal investigators are still working and they have not released
    their final results (that's due in just a couple of months). But so far, the
    results have been somewhat inconclusive. There was more noise in the system
    than expected. The gyros were torqued by patches on their surfaces with
    different electrostatic properties. Although the so-called "geodetic"
    precession has been detected, some questions have been raised about the
    level of confidence. And at least so far, it has not been possible to model
    enough of the remaining noise to see the smaller frame-dragging effect (the
    idea is that if you can model it reliably, you can subtract it from the
    observed data). Here's a press release from last spring:
    http://einstein.stanford.edu/content/press_releases/SU/pr-aps-041807.pdf
    
    Incidentally, there's no connection between GP-B and the earlier "Gravity
    Probe A" which was a high-altitude, sub-orbital flight with an atomic clock
    which provided detailed confirmation of special relativistic and general
    relativistic time dilation (the gravitational redshift).
    
     -FER
    
    
    --~--~---------~--~----~------------~-------~--~----~
    To post to this group, send email to NavList@fer3.com
    To unsubscribe, send email to NavList-unsubscribe@fer3.com
    -~----------~----~----~----~------~----~------~--~---
    
    

       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Join NavList

    Name:
    (please, no nicknames or handles)
    Email:
    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:

    Email Settings

    Posting Code:

    Custom Index

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

    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site