PRESENT STATUS OF THE STUDY OF THE ANOMALOUS ACCELERATION OF THE PIONEER 10/11 SPACECRAFT

2005 ◽  
Vol 20 (11) ◽  
pp. 2304-2308 ◽  
Author(s):  
J. P. MBELEK
Keyword(s):  
Weak Field ◽  
Low Velocity ◽  
Pioneer Anomaly ◽  
Real Change ◽  
Local Manifestation ◽  
Anomalous Acceleration ◽  
Expansion Of The Universe ◽  
The Universe ◽  
Pioneer 10 ◽  
Radiometric Data

Results from an almost twenty years study of radiometric data from Pioneer 10/11, Galileo and Ulysses spacecraft indicate an anomalous time depending blueshift1, 2 which bares hardly prosaic explanations. Local manifestation of the expansion of the universe or new force terms are not favored either by the observational data. So, we explore the possibility that the reported anomaly, referred to as the "Pioneer anomaly", does not result from a real change in velocity. It turns out that the main Pioneer anomaly may be looked at as a new validation of general relativity (GR) in the weak field and low velocity limit on account of the "machian" behavior of quintessence like dark energy.

scholarly journals A STUDY OF THE PIONEER ANOMALY: NEW DATA AND OBJECTIVES FOR NEW INVESTIGATION

2006 ◽  
Vol 15 (01) ◽  
pp. 1-55 ◽  
Author(s):  
SLAVA G. TURYSHEV ◽  
VIKTOR T. TOTH ◽  
LARRY R. KELLOGG ◽  
EUNICE L. LAU ◽  
KYONG J. LEE
Keyword(s):  
Current Knowledge ◽  
Doppler Frequency ◽  
Blue Shift ◽  
Data Sets ◽  
Pioneer Anomaly ◽  
Doppler Data ◽  
History Of ◽  
Anomalous Acceleration ◽  
Pioneer 10

The Pioneer 10/11 spacecraft yielded the most precise navigation in deep space to date. However, their radiometric tracking data has consistently indicated the presence of a small, anomalous, Doppler frequency drift. The drift is a blue shift, uniformly changing with a rate of ~6 × 10-9 Hz/s and can be interpreted as a constant sunward acceleration of each particular spacecraft of aP = (8.74±1.33) × 10-10 m/s 2 (or, alternatively, a time acceleration of at = (2.92±0.44) × 10-18 s/s 2). This signal has become known as the Pioneer anomaly; the nature of this anomaly remains unexplained. We discuss the current state of the efforts to retrieve the entire data sets of the Pioneer 10 and 11 radiometric Doppler data. We also report on the availability of recently recovered telemetry files that may be used to reconstruct the engineering history of both spacecraft using original project documentation and newly developed software tools. We discuss possible ways to further investigate the discovered effect using these telemetry files in conjunction with the analysis of the much extended Pioneer Doppler data. In preparation for this new upcoming investigation, we summarize the current knowledge of the Pioneer anomaly and review some of the mechanisms proposed for its explanation. We emphasize the main objectives of this new study, namely (i) analysis of the early data that could yield the true direction of the anomaly and thus, its origin, (ii) analysis of planetary encounters, which should say more about the onset of the anomaly (e.g. Pioneer 11's Saturn flyby), (iii) analysis of the entire dataset, which should lead to a better determination of the temporal behavior of the anomaly, (iv) comparative analysis of individual anomalous accelerations for the two Pioneers with the data taken from similar heliocentric distances, (v) the detailed study of on-board systematics, and (vi) development of a thermal-electric-dynamical model using on-board telemetry. The outlined strategy may allow for a higher accuracy solution for the anomalous acceleration of the Pioneer spacecraft and, possibly, will lead to an unambiguous determination of the origin of the Pioneer anomaly.

scholarly journals Conformal Cosmology and the Pioneer Anomaly

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Gabriele U. Varieschi
Keyword(s):  
Cosmological Parameters ◽  
Hubble Constant ◽  
Conformal Gravity ◽  
Conformal Cosmology ◽  
Pioneer Anomaly ◽  
Radio Signals ◽  
Anomalous Acceleration ◽  
Near Future ◽  
Pioneer 10

We review the fundamental results of a new cosmological model, based on conformal gravity, and apply them to the analysis of the early data of the Pioneer anomaly. We show that our conformal cosmology can naturally explain the anomalous acceleration of the Pioneer 10 and 11 spacecrafts, in terms of a local blueshift region extending around the solar system and therefore affecting the frequencies of the navigational radio signals exchanged between Earth and the spacecraft. By using our model, we explain the numerical coincidence between the value of the anomalous acceleration and the Hubble constant at the present epoch and also confirm our previous determination of the cosmological parameters γ∼10−28 cm−1 and δ~10-4–10-5. New Pioneer data are expected to be publicly available in the near future, which might enable more precise evaluations of these parameters.

THE LIGHT SPEED AND THE INTERPLAY OF THE QUANTUM VACUUM, THE GRAVITATION OF ALL THE UNIVERSE AND THE FOURTH HEISENBERG RELATION

2003 ◽  
Vol 12 (09) ◽  
pp. 1755-1762 ◽  
Author(s):  
ANTONIO F. RAÑADA
Keyword(s):  
Fine Structure ◽  
Structure Constant ◽  
Fine Structure Constant ◽  
Quantum Vacuum ◽  
Proposed Model ◽  
Anomalous Acceleration ◽  
Heisenberg Relation ◽  
The Universe ◽  
Observational Signature ◽  
Pioneer 10

A recently proposed model which accounts for the observed time dependence of the fine structure constant is summarized. The model is based on the combined effect of the fourth Heisenberg relation and the gravitation of all the expanding universe on the quantum vacuum. As is shown here, it predicts that the light must have now an acceleration close to H0c≃6.9×10-10 m/s2. This suggests an explanation of the anomalous acceleration aP≃8.5×10-10 m/s2 found in the Pioneer 10 spacecraft, because an acceleration of light has the same radio observational signature as an acceleration of the ship.

A model for the pioneer anomaly

2009 ◽  
Vol 87 (10) ◽  
pp. 1089-1093 ◽  
Author(s):  
Ivan G. Avramidi ◽  
Guglielmo Fucci
Keyword(s):  
General Relativity ◽  
Test Particles ◽  
Pioneer Anomaly ◽  
Modified Theory Of Gravity ◽  
Anomalous Acceleration ◽  
Theory Of Gravity ◽  
Modified Theory ◽  
Pioneer 10

In a previous work, we showed that massive test particles exhibit a nongeodesic acceleration in a modified theory of gravity obtained by a noncommutative deformation of General Relativity (so-called Matrix Gravity). We propose that this nongeodesic acceleration might be the origin of the anomalous acceleration experienced by the Pioneer 10 and Pioneer 11 spacecrafts.

scholarly journals CAN CONVENTIONAL FORCES REALLY EXPLAIN THE ANOMALOUS ACCELERATION OF PIONEER 10/11?

2004 ◽  
Vol 13 (05) ◽  
pp. 865-870 ◽  
Author(s):  
J. P. MBELEK ◽  
M. MICHALSKI
Keyword(s):  
Observational Data ◽  
Doppler Shift ◽  
Reaction Force ◽  
Rate Change ◽  
Shift Analysis ◽  
Pioneer Anomaly ◽  
Anomalous Acceleration ◽  
Pioneer 10 ◽  
Good Agreement

A conventional explanation of the correlation between the linear and the angular accelerations of Pioneer 10/11 spacecraft is given. First, the rotational Doppler shift analysis is improved. Finally, a relation between the radio beam reaction force and the spin-rate change is established. Computations are found in good agreement with observational data. Our analysis leads us to the conclusion that the Pioneer anomaly may not necessarily be due to systematics.

scholarly journals On the possible onset of the Pioneer anomaly

2015 ◽  
Vol 24 (08) ◽  
pp. 1550066 ◽  
Author(s):  
Michael R. Feldman ◽  
John D. Anderson
Keyword(s):  
Solar Radiation Pressure ◽  
Sudden Onset ◽  
Oscillatory Behavior ◽  
Pioneer Anomaly ◽  
Order Of Magnitude ◽  
Anomalous Acceleration ◽  
The Difference ◽  
Definition Of ◽  
Yearly Period ◽  
Pioneer 10

We explore the possibility that the observed onset of the Pioneer anomaly after Saturn encounter by Pioneer 11 is not necessarily due to mismodeling of solar radiation pressure but instead reflects a physically relevant characteristic of the anomaly itself. We employ the principles of a recently proposed cosmological model termed "the theory of inertial centers" along with an understanding of the fundamental assumptions taken by the Deep Space Network (DSN) to attempt to model this sudden onset. Due to an ambiguity that arises from the difference in the DSN definition of expected light-time with light-time according to the theory of inertial centers, we are forced to adopt a seemingly arbitrary convention to relate DSN-assumed clock-rates to physical clock-rates for this model. We offer a possible reason for adopting the convention employed in our analysis; however, we remain skeptical. Nevertheless, with this convention, one finds that this theory is able to replicate the previously reported Hubble-like behavior of the "clock acceleration" for the Pioneer anomaly as well as the sudden onset of the anomalous acceleration after Pioneer 11 Saturn encounter. While oscillatory behavior with a yearly period is also predicted for the anomalous clock accelerations of both Pioneer 10 and Pioneer 11, the predicted amplitude is an order of magnitude too small when compared with that reported for Pioneer 10.

Black Hole Universe: a grand cosmic recycler and Big Bang generator?

2019 ◽  
Author(s):  
Matheus Pereira Lobo
Keyword(s):  
Black Hole ◽  
Big Bang ◽  
Subsequent Increase ◽  
Expansion Of The Universe ◽  
The Universe

We propose the discussion of a highly speculative idea for the scenario where black hole collisions and their subsequent increase in sizes exceed the expansion of the universe.

Cosmological constant

2018 ◽  
Author(s):  
Michael Kachelriess
Keyword(s):  
Dark Energy ◽  
Cosmological Constant ◽  
Accelerated Expansion ◽  
Vacuum Fluctuations ◽  
Present Epoch ◽  
Modify Gravity ◽  
Expansion Of The Universe ◽  
The Universe

The contribution of vacuum fluctuations to the cosmological constant is reconsidered studying the dependence on the used regularisation scheme. Then alternative explanations for the observed accelerated expansion of the universe in the present epoch are introduced which either modify gravity or add a new component of matter, dubbed dark energy. The chapter closes with some comments on attempts to quantise gravity.

scholarly journals Mixed fluid cosmological model in f(R, T) gravity

2020 ◽  
Vol 98 (11) ◽  
pp. 1015-1022 ◽  
Author(s):  
Parbati Sahoo ◽  
Barkha Taori ◽  
K.L. Mahanta
Keyword(s):  
Cosmological Model ◽  
Bianchi Type ◽  
Type I ◽  
Time Varying ◽  
Eos Parameter ◽  
Barotropic Fluid ◽  
Rotationally Symmetric ◽  
Expansion Of The Universe ◽  
The Universe ◽  
Mixed Fluid

We construct a locally rotationally symmetric (LRS) Bianchi type-I cosmological model in f(R, T) theory of gravity when the source of gravitation is a mixture of barotropic fluid and dark energy (DE) by employing a time-varying deceleration parameter. We observe through the behavior of the state finder parameters (r, s) that our model begins from the Einstein static era and goes to ΛCDM era. The equation of state (EOS) parameter (ωd) for DE varies from the phantom (ω < –1) phase to quintessence (ω > –1) phase, which is consistent with observational results. It is found that the discussed model can reproduce the current accelerating phase of the expansion of the universe.

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