Matches in DBpedia 2015-10 for { <http://dbpedia.org/resource/Pioneer_anomaly> ?p ?o }
- Pioneer_anomaly abstract "The Pioneer anomaly or Pioneer effect was the observed deviation from predicted accelerations of the Pioneer 10 and Pioneer 11 spacecraft after they passed about 20 astronomical units (3×109 km; 2×109 mi) on their trajectories out of the Solar System. The apparent anomaly was a matter of tremendous interest for many years, but has been subsequently explained by an anisotropic radiation pressure caused by the spacecraft's heat loss.Both Pioneer spacecraft are escaping the Solar System, but are slowing under the influence of the Sun's gravity. Upon very close examination of navigational data, the spacecraft were found to be slowing slightly more than expected. The effect is an extremely small acceleration towards the Sun, of 6990874000000000000♠(8.74±1.33)×10−10 m/s2, which is equivalent to slowly accelerating to a velocity of 1 kilometre per hour (0.6 mph) over a period of ten years. The two spacecraft were launched in 1972 and 1973 and the anomalous acceleration was first noticed as early as 1980, but not seriously investigated until 1994. The last communication with either spacecraft was in 2003, but analysis of recorded data continues.Various explanations, both of spacecraft behavior and of gravitation itself, were proposed to explain the anomaly. Over the period 1998–2012, one particular explanation became accepted. The spacecraft, which are surrounded by an ultra-high vacuum and are each powered by a radioisotope thermoelectric generator (RTG), can shed heat only via thermal radiation. If, due to the design of the spacecraft, more heat is emitted in a particular direction—what is known as a radiative anisotropy—then the spacecraft would accelerate slightly in the direction opposite of the excess emitted radiation due to radiation pressure. Because this force is due to the recoil of thermal photons, it is also called the thermal recoil force. If the excess radiation and attendant radiation pressure were pointed in a general direction opposite the Sun, the spacecraft's velocity away from the Sun would be decelerating at a greater rate than could be explained by previously recognized forces, such as gravity and trace friction, due to the interplanetary medium (imperfect vacuum).By 2012 several papers by different groups, all reanalyzing the thermal radiation pressure forces inherent in the spacecraft, showed that a careful accounting of this explains the entire anomaly, and thus the cause was mundane and did not point to any new phenomena or need for a different physical paradigm. The most detailed analysis to date, by some of the original investigators, explicitly looks at two methods of estimating thermal forces, then states "We find no statistically significant difference between the two estimates and conclude that once the thermal recoil force is properly accounted for, no anomalous acceleration remains."".
- Pioneer_anomaly wikiPageExternalLink 2002138196_pioneer02.html.
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- Pioneer_anomaly wikiPageExternalLink pa-literature.htm.
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- Pioneer_anomaly wikiPageExternalLink mystery_monday_041018.html.
- Pioneer_anomaly wikiPageExternalLink TPS_Enables_Study_Of_Mysterious_Pioneer_Anomaly.html.
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- Pioneer_anomaly wikiPageID "980666".
- Pioneer_anomaly wikiPageLength "50463".
- Pioneer_anomaly wikiPageOutDegree "110".
- Pioneer_anomaly wikiPageRevisionID "683693661".
- Pioneer_anomaly wikiPageWikiLink Acceleration.
- Pioneer_anomaly wikiPageWikiLink Accelerations.
- Pioneer_anomaly wikiPageWikiLink Anisotropy.
- Pioneer_anomaly wikiPageWikiLink Asteroid.
- Pioneer_anomaly wikiPageWikiLink Astronomical_Unit.
- Pioneer_anomaly wikiPageWikiLink Astronomical_unit.
- Pioneer_anomaly wikiPageWikiLink Astronomy_(magazine).
- Pioneer_anomaly wikiPageWikiLink Astronomy_Magazine.
- Pioneer_anomaly wikiPageWikiLink Attitude_control.
- Pioneer_anomaly wikiPageWikiLink Bern.
- Pioneer_anomaly wikiPageWikiLink Casimir_effect.
- Pioneer_anomaly wikiPageWikiLink Cassini-Huygens.
- Pioneer_anomaly wikiPageWikiLink Cassini–Huygens.
- Pioneer_anomaly wikiPageWikiLink Category:Gravitation.
- Pioneer_anomaly wikiPageWikiLink Category:Pioneer_program.
- Pioneer_anomaly wikiPageWikiLink Classical_and_Quantum_Gravity.
- Pioneer_anomaly wikiPageWikiLink Conical_scanning.
- Pioneer_anomaly wikiPageWikiLink Cosmic_microwave_background.
- Pioneer_anomaly wikiPageWikiLink Cosmic_microwave_background_radiation.
- Pioneer_anomaly wikiPageWikiLink Cosmic_ray.
- Pioneer_anomaly wikiPageWikiLink Cosmic_rays.
- Pioneer_anomaly wikiPageWikiLink Cosmic_time.
- Pioneer_anomaly wikiPageWikiLink Dark_matter.
- Pioneer_anomaly wikiPageWikiLink Deceleration.
- Pioneer_anomaly wikiPageWikiLink Density.
- Pioneer_anomaly wikiPageWikiLink Directional_antenna.
- Pioneer_anomaly wikiPageWikiLink Doppler_effect.
- Pioneer_anomaly wikiPageWikiLink Drag_(physics).
- Pioneer_anomaly wikiPageWikiLink Dust.
- Pioneer_anomaly wikiPageWikiLink Earth.
- Pioneer_anomaly wikiPageWikiLink Ephemeris.
- Pioneer_anomaly wikiPageWikiLink Equivalence_principle.
- Pioneer_anomaly wikiPageWikiLink Expanding_universe.
- Pioneer_anomaly wikiPageWikiLink Flyby_anomaly.
- Pioneer_anomaly wikiPageWikiLink Friedmann–Lemaître–Robertson–Walker_metric.
- Pioneer_anomaly wikiPageWikiLink Galileo_(spacecraft).
- Pioneer_anomaly wikiPageWikiLink Galileo_spacecraft.
- Pioneer_anomaly wikiPageWikiLink Gas.
- Pioneer_anomaly wikiPageWikiLink Gravitational.
- Pioneer_anomaly wikiPageWikiLink Gravitational_physics.
- Pioneer_anomaly wikiPageWikiLink Gravity.
- Pioneer_anomaly wikiPageWikiLink Gyroscope.
- Pioneer_anomaly wikiPageWikiLink Helium.
- Pioneer_anomaly wikiPageWikiLink High-gain_antenna.
- Pioneer_anomaly wikiPageWikiLink Hubble_constant.
- Pioneer_anomaly wikiPageWikiLink Hubbles_law.
- Pioneer_anomaly wikiPageWikiLink Huygens_(spacecraft).
- Pioneer_anomaly wikiPageWikiLink Huygens_probe.
- Pioneer_anomaly wikiPageWikiLink Hyperbolic_trajectory.
- Pioneer_anomaly wikiPageWikiLink Hypothesis.
- Pioneer_anomaly wikiPageWikiLink International_Atomic_Time.
- Pioneer_anomaly wikiPageWikiLink International_Journal_of_Modern_Physics.
- Pioneer_anomaly wikiPageWikiLink International_Journal_of_Modern_Physics_D.
- Pioneer_anomaly wikiPageWikiLink International_Space_Science_Institute.
- Pioneer_anomaly wikiPageWikiLink Interplanetary_medium.
- Pioneer_anomaly wikiPageWikiLink Jet_Propulsion_Laboratory.
- Pioneer_anomaly wikiPageWikiLink Jupiter.
- Pioneer_anomaly wikiPageWikiLink Kilometre.
- Pioneer_anomaly wikiPageWikiLink Kuiper_belt.
- Pioneer_anomaly wikiPageWikiLink LAGEOS.
- Pioneer_anomaly wikiPageWikiLink Lunar_Laser_Ranging_experiment.
- Pioneer_anomaly wikiPageWikiLink Metric_expansion_of_space.
- Pioneer_anomaly wikiPageWikiLink Modified_Newtonian_dynamics.
- Pioneer_anomaly wikiPageWikiLink Monopropellant_rocket.
- Pioneer_anomaly wikiPageWikiLink New_Horizons.
- Pioneer_anomaly wikiPageWikiLink Outer_space.
- Pioneer_anomaly wikiPageWikiLink Photon.
- Pioneer_anomaly wikiPageWikiLink Physical_Review.
- Pioneer_anomaly wikiPageWikiLink Physical_Review_D.
- Pioneer_anomaly wikiPageWikiLink Physical_Review_Letters.
- Pioneer_anomaly wikiPageWikiLink Physical_cosmology.
- Pioneer_anomaly wikiPageWikiLink Pioneer_10.
- Pioneer_anomaly wikiPageWikiLink Pioneer_11.
- Pioneer_anomaly wikiPageWikiLink Pioneer_Explorer_Collaboration.
- Pioneer_anomaly wikiPageWikiLink Pluto.
- Pioneer_anomaly wikiPageWikiLink Proper_time.
- Pioneer_anomaly wikiPageWikiLink Radiation_pressure.
- Pioneer_anomaly wikiPageWikiLink Radio_signal.
- Pioneer_anomaly wikiPageWikiLink Radio_wave.
- Pioneer_anomaly wikiPageWikiLink Radioisotope_thermoelectric_generator.
- Pioneer_anomaly wikiPageWikiLink Radioisotope_thermoelectric_generators.
- Pioneer_anomaly wikiPageWikiLink Reaction_wheel.
- Pioneer_anomaly wikiPageWikiLink Redshift.