Monday, April 16, 2007

Gravity Probe B: frame-dragging twice smaller than resolution

Gravity Probe B, a \$700 million NASA satellite experiment with gyroscopes controlled from Stanford University, an experiment that started more than 40 years ago (the oldest physics experiment alive) and that was designed to verify the effect of frame-dragging predicted by general relativity, is still unable to say Yes or No. Rotating Earth should "drag" the space around with it and transfer some angular momentum from the Earth to other objects.

The observed change of the axis of rotation of the gyroscopes can clearly measure the geodetic effect with the accuracy of 1% but the predicted frame-dragging - a general relativistic effect that is the closest reminder of the Mach principle, a flawed principle that motivated Einstein to find a new theory of gravity but one that was eventually refuted - is about twice as small as their current error margin.

They hope to get better results by the end of 2007: see press release.

1 comment:

  1. The uncertainties are twice the predicted effect. Even in this accuracy the result of the experiment would have killed TGD or at least TGD inspired model for gravitomagnetic field of rotating object unless the satellite had been on equator where the predictions of TGD and GRT are identical.

    Kerr solution is very probably not imbeddable in 8-D imbedding space of TGD and the simplest vacuum extremal modifying Schwartschild solution carries gravimagnetic field which behaves as 1/r^3 like also dipole field but the radial component is lacking. The flux flows along z-axis where it emanates radially and flows along spheres.

    Near poles the gravimagnetic effect becomes much stronger than in GRT and this would provide a test killing either GRT- or TGD-inspired model (or GRT or TGD if you like). I do not however expect that this experiment will be carried in the near future;-). For TGD prediction see this or this.

    Matti Pitkanen