Gravity Probe B, results trickle out

Posted: May 18, 2011 by tchannon in Astrophysics, Solar physics, solar system dynamics

(image clickable)

One of the oldest space experiments which has taken many years of post flight data processing is now concluded.

A provisional copy of the primary paper is now available Gravity Probe B: Final Results of a Space Experiment to Test General Relativity

The experimental data , so far not released, might contain new information about the solar system, the sun and perhaps as a few people have written, about the path of the sun through space.

The mission was essentially a technical failure when malfunctions became obvious and was cancelled by NASA. The science team then managed with great difficulty to find funding for the completion of a very difficult data correction operation.

Unexpected gyroscope problems were the main difficulty.

I noticed the mission uses star pointing, the far distance fixed orientation reference. The method is stated as using dither but I have a background in signal processing and what is described I do not recognise as dither. The point of dither is the magic of completely incoherent noise, which then is valid for simple statistics, simple data average: the noise reducing, any signal is coherent and stays put. (hence a single data bit can be processed to 24 or more bits in data converters; a simile is a fluidise bed such as sand with water flowing through it, randomly jiggling the grains so that they behave as a liquid)

A petal pattern for dither?

The question now is what else is in the data if anything?

  1. Roger Andrews says:

    Hi Tim: Nothing directly to do with this thread, but could you send me an e-mail so that I have your address? I have some solar stuff I would like to send you. Thanks. R

  2. Tim Channon says:

    NOTE: May be offline for a few days. I have serious computer problems, managed to get it to start (after several hours), have to try and source a new compatible motherboard, nothing else left other than CPU. Faultless provided it starts, been growing a fault for a couple of years. No beeps, no messages.

    Roger: done

    [update] hopefully I am back with a new motherboard working, only time will tell now. I’ll pull this comment soon.

  3. P.G. Sharrow says:

    The gyros may be working well and just giving data that does not fit what was expected.
    Travel in 3 dimentions at different velocities will cause warpage in the presessions of the gyros. The mass/inertia of the earth will also cause changes depending on the oreintation of the gyros to the earth. Quite a can of worms to untangle. pg

  4. @P.G. Sharrow says:
    May 19, 2011 at 3:41 am
    “….Quite a can of worms to untangle. “…..unless EM is considered: A gyro composed of perfect circles elongates, increasing its “eccentricity”. The problem is that, from the point of view of the “pebbles universe”working only by gravity, “bodies” remain as such, no matter how big the parameters are (Fred Flinstones¨principle). If we were to consider the movement of the earth as from a perspective (parameters) say of a thousand light years, should we consider it a particle or a wave?

  5. @P.G. : You saw it right: Your “worms”= Sin + Cos waves = power. Wheresoever there is movement of mass there is power, and in certain conditions all the wavelengths we should like. See?, “size” (dimension) it is a very important thing.
    Some would prefer seeing those worms being of two kinds: Ying and Yang, and in different proportions and harmonics, like the ratios of an square triangle, like 2:3 =.666, the “perfect fifth”.

  6. Malaga View says:

    The B Ark tag is more appropriate for this nonsense….

    The useless third of the population that did not actually produce anything (middle men, people in service industries) were packed into the B-Ark, one of three giant Ark spaceships, and told that everyone else would follow shortly in the other two. The other two thirds of the population, of course, did not follow.

    Miles Mathis has tagged this as Another debacle from NASA.

    In a nutshell, what the Gravity Probe experiment did is measure the tilt of little gyroscopes.
    If the tilt is zero, no curvature of space-time.
    If the tilt is not zero, we are supposed to have proof of curvature.
    The gyroscope tilts because space is curved.

    The primary problem is that there is absolutely no effort in this experiment to consider, mention, or try to block the main cause of that tilt. It is simply assumed that any non-zero outcome is proof positive of their theory and that any tilt that does not match their needed numbers is only an anomaly or “observation” that can be explained away later. That is horrible science, no matter how you look at it.

    And then there is the very interesting horseshoe shaped orbit of Asteroid 2010 SO16

    Asteroid 2010 SO16 takes 175 years to make the trip from one end of the horseshoe to the other. So while on the one hand its orbit is remarkably similar to Earth’s, in fact, according to Dr. Christou:
    This asteroid is “terraphobic.” It keeps well away from the Earth. So well, in fact, that it has likely been in this orbit for several hundred thousand years, never coming closer to our planet than 50 times the distance to the moon.
    This is where it is now, near the end of the horseshoe trailing the Earth.

    Wikipedia explains the horseshoe orbit using gravity:

    While Miles Mathis, again, identifies the B Ark nonsense…

    The distance between asteroid and Earth is diminishing with time, so the gravitational force between them must be increasing rapidly. The distance between Sun and asteroid is not yet changing at these points (it changes soon afterwards), so the force between Sun and asteroid is not changing. Therefore, we may ask what would make the asteroid make a 90o turn at this point in its motion. Even more to the point, what would make it turn another 90o and move away from the Earth? We need a force or other mechanical cause here, not just math or field lines. Neither math nor field lines can turn an asteroid. The force of gravity, which is supposed to be beneath these field lines, defining them, cannot possibly cause the asteroid to turn around and move away. Gravity is a force of attraction, remember?

  7. tchannon says:

    I suggest reconsidering the horseshoe orbit.

    The problem is I think an atrocious usage of description. Wikipedia does say this “its path appears to have a horseshoe shape in a rotating reference frame as viewed from the larger object.”
    The horseshoe shape does not exist, is an abstraction.

    Both the earth and the asteroid are in roughly circular orbits of rough the same size and period, ie. the asteroid has a close to identical orbit.

    Key is the slight velocity difference and is actually a bistable state, either faster or slower than earth.

    The modal switch occurs when the asteroid approaches earth.

    1. Ast, is chasing earth, moving faster and therefore in an orbit closer to the sun. As gravitational attraction starts to work it is attracted outwards to a further out orbit, which must be slower. It is then travelling slower than the earth and falls behind.

    2. Reverse of (1)

    Whole thing is bizarre but it is the real world.

  8. Malaga View says:

    Well I agree that the Wiki thing is bizarre :-)

  9. Tim Channon says:

    I wondered about modelling it, ought to be possible.

    The implication is very different mass bodies in the same orbit will not collide. Is that how eg. rings of Saturn stay in place except the masses are similar?

  10. Zeke the Sneak says:

    “GP-B scientists soon found, however, that the rotors were not just tracing a well-known Newtonian pattern with tiny sidesteps predicted by Einstein. Rather, those spinning rotors were also heeding a third influence: electromagnetism. The final patch of niobium sprayed onto the rotors had effectively polarized the sphere and left a tiny surplus charge that, when spun up and translated into magnetic fields, added a new layer of wobble to account for. GP-B collected data for 353 days in 2004 and 2005 and then spent an additional 46 days conducting tests on the gyros to deduce precisely where those additional tiny magnetic fields lay.”

    Each of the niobium coated gyros behaved differently, and anyway the precision required to get any meaningful results from this experiment is just beyond belief in the first place. Well did NASA cut off funding for this.

  11. @Zeke the Sneak says:
    May 21, 2011 at 4:23 pm

    Next time they will have to make their gyros out of just “dream matter”….it will be cheaper and more poetic anyway!

  12. Zeke the Sneak says:

    Yes Adolfo :D “Einstein’s Dream Gyros”

    Only, I don’t think he would really approve of this kind of manipulation and maneuvering to try to prove his theory.

  13. tchannon says:

    From mailing list today


    ThePRL GP-B paper summarizing the final results was published today (Physical Review Letters 106, 221101, 2011).

    The GP-B PRL letter was accompanied by a Physics Viewpoint article by Clifford Will (Professor of Physics at Washington University and Chairman of the GP-B Science Advisory Committee.) Professor Will’s Viewpoint is entitled: “Finally, Results from Gravity Probe B.”

    If you are a member of the APS, you can view/download a PDF copy of the PRL paper on the APS website at:

    Anyone can view/download Professor Will’s Viewpoint article at:
    (There is also a link to a free PDF copy of the GP-B PRL paper on this page.)

    In addition, we have posted both the PRL paper and Professor Will’s Viewpoint article, including PDF copies, on the Current Mission Status Page of our GP-B website:

    We enjoyed reading and very much appreciate all of the email messages we have received from around the world over the past few weeks.

    For me, it’s been a pleasure and an honor serving as the “public voice” of this landmark experiment and mission.

    On behalf of the entire GP-B team (and all of our many alumni), I thank you for your continued support and interest.

    Most Sincerely,

    Bob Kahn
    Gravity Probe B Public Affairs Coordinator & Webmaster

    NASA – Stanford – Lockheed Martin
    Gravity Probe B Program
    “Testing Einstein’s Universe”

    Bob Kahn
    Public Affairs Coordinator & Webmaster “