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SinghRP
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Does general relativity explain the Pioneer effect and the spacecraft flyby anomaly? I have seen several papers on those two topics but no GR explanation.
SinghRP, I have read the link, and it gives a full explanation. Suggest you do too!Meanwhile, have you read whether GRT explains either or both?
SinghRP said:I will access the link, read, and come back to you.
Meanwhile, have you read whether GRT explains either or both? Please be specific; will appreciate it.
Bill_K said:SinghRP, I have read the link, and it gives a full explanation. Suggest you do too!
Yep, you're right. Sorry.I don't think the linked article/paper explains the Flyby anomaly, or does it?
ZapperZ said:There appears to be no mystery with these space crafts. Did you miss this news?
http://physicsworld.com/cws/article...tic-explanation-for-pioneer-anomaly-ruled-out
Zz.
davidf32 said:It is interesting to look at the actual data for the anomalous acceleration. it is available at:
arXiv: gr-qc/0104064v5
What one sees is three distinct signatures;
(1) The effect gradually appears over a distance of about 5 AU or so reaching a maximum of about 10*10^-8 cm/sec^2 at 20 AU and staying more or less constant after that out to at least 70AU.
(2) There is a definite yearly small variation in the magnitude at a certain position related to the Earth's rotation around the sun in its orbit
(3) There is a much larger (order of 100*10^-8 cm/sec^2) term with a period equal to the Earth's period of rotation (24 hours)
IN view of these facts, the thermal explanation does not seem valid: It should appear much sooner than 5 AU, more or less all the time; it does not address either the small annual term or the diurnal large term. I don't believe the thermal explanation.
davidf32.
The error bars below 15 AU are so large, I would not trust those values.(1) The effect gradually appears over a distance of about 5 AU or so reaching a maximum of about 10*10^-8 cm/sec^2 at 20 AU and staying more or less constant after that out to at least 70AU.
davidf32 said:(2) There is a definite yearly small variation in the magnitude at a certain position related to the Earth's rotation around the sun in its orbit
(3) There is a much larger (order of 100*10^-8 cm/sec^2) term with a period equal to the Earth's period of rotation (24 hours)
In short: If you don't know the exact position of the spacecraft , you get some wiggles due to the motion of earth. This does not influence the average, however.Paper said:The annual and diurnal terms are very likely different
manifestations of the same modeling problem. The magnitude
of the Pioneer 10 post-fit weighted RMS residuals
of ≈ 0.1 mm/s, implies that the spacecraft angular position
on the sky is known to ≤ 1.0 milliarcseconds (mas).
(Pioneer 11, with ≈ 0.18 mm/s, yields the result ≈ 1.75
mas.) At their great distances, the trajectories of the
Pioneers are not gravitationally affected by the Earth.
(The round-trip light time is now ∼ 24 hours for Pioneer
10.) This suggests that the sources of the annual and
diurnal terms are both Earth related.
Such a modeling problem arises when there are errors
in any of the parameters of the spacecraft orientation
with respect to the chosen reference frame. Because
of these errors, the system of equations that describes
the spacecraft ’s motion in this reference frame
is under-determined and its solution requires non-linear
estimation techniques. In addition, the whole estimation
process is subject to Kalman filtering and smoothing
methods. Therefore, if there are modeling errors in
the Earth’s ephemeris, the orientation of the Earth’s spin
axis (precession and nutation), or in the station coordinates
(polar motion and length of day variations), the
least-squares process (which determines best-fit values of
the three direction cosines) will leave small diurnal and
annual components in the Doppler residuals, like those
seen in Figures 17-18.
When you have published your idea in a mainstream physics journal then it can be discussed here. Until then it is unfounded and unsubstantiated speculation.SinghRP said:I think the effects could be due to variations in the classical gravitation constant G.
The Pioneer effect is a phenomenon observed in the trajectories of spacecrafts launched by NASA, particularly the Pioneer 10 and 11 spacecrafts. It refers to a small, unexplained acceleration in the spacecrafts' trajectories that cannot be accounted for by known forces, such as gravitational pull from planets or solar radiation pressure.
The Spacecraft flyby anomaly, also known as the flyby anomaly or the anomaly of flyby spacecraft, is a similar phenomenon observed in the trajectories of spacecrafts that perform gravitational slingshot maneuvers around planets. It refers to an unexpected increase in speed of the spacecraft after the maneuver, which cannot be explained by known forces.
Some proposed explanations for these anomalies include systematic errors in the spacecrafts' measurements, thermal recoil force from the spacecrafts' radioisotope thermoelectric generators, and the influence of dark matter or modified theories of gravity.
The magnitude of the Pioneer effect is very small, with an acceleration of only about 8.74x10^-10 meters per second squared. The Spacecraft flyby anomaly is even smaller, with an acceleration of about 1x10^-8 meters per second squared. However, these small accelerations can accumulate over time and have a significant impact on the spacecrafts' trajectories.
Yes, there have been multiple attempts to replicate and verify the Pioneer effect and Spacecraft flyby anomaly. In 2005, NASA launched the Gravity Probe B satellite to test Einstein's theory of general relativity, but it also collected data on the Pioneer effect and confirmed its existence. In addition, the European Space Agency's Gaia mission and the Japanese Aerospace Exploration Agency's Hayabusa spacecraft have also collected data on these anomalies.