For Your Eyes Only
The Enigmatic Lunar Magnetic Field:
A Search for Answers
NASA News Release Nov 6, 2006

...something bizarre happened.

The orbit of PFS-2 rapidly changed shape and distance from the Moon. In 2-1/2 weeks the satellite was swooping to within a hair-raising 6 miles (10 km) of the lunar surface at closest approach. As the orbit kept changing, PFS-2 backed off again, until it seemed to be a safe 30 miles away. But not for long: inexorably, the subsatellite's orbit carried it back toward the Moon. And on May 29, 1972—only 35 days and 425 orbits after its release—PFS-2 crashed.

SOURCE: NASA News Release

Lunar Prospector
Image Credit: NASA
The Lunar Prospector mission was the third selected by NASA for full development and construction as part of the Discovery Program. At a cost of $62.8 million, the 19-month mission was designed for a low polar orbit investigation of the Moon, including mapping of surface composition and possible polar ice deposits, measurements of magnetic and gravity fields, and study of lunar outgassing events. The mission ended July 31, 1999 when the orbiter was deliberately crashed into a crater near the lunar south pole in an unsuccessful attempt to detect the presence of water.

Data from the mission allowed the construction of a detailed map of the surface composition of the Moon, and helped to improve understanding of the origin, evolution, current state, and resources of the Moon. A series of articles on the scientific results were published in the journal Science (Science Volume 281 Issue 5382).

The Principal Investigator for the mission was Dr. Alan Binder. His personal account of the mission "Against all Odds" (published in 2005 by KenPress, ISBN 1-928771-31-9) is highly critical of the bureaucracy of NASA and its contractors.

Electron Reflectometer and Magnetometer

The Magnetometer and Electron Reflectometer (collectively, MAG/ER) detected anomalous surface magnetic fields on the Moon, which are in stark contrast to a global magnetosphere (which the Moon lacks). The Moon's overall magnetic field is too weak to deflect the solar wind, but MAG/ER discovered a small surface anomaly that can do so. This anomaly, about 100 km in diameter, has therefore been referred to as "the smallest known magnetosphere, magnetosheath and bow shock system in the Solar System" (NASA/ARC). Due to this and other magnetic features of the Moon's surface, hydrogen deposited by solar wind is non-uniformly distributed, being denser at the periphery of the magnetic features. Since hydrogen density is a desirable characteristic for hypothetical lunar bases, this information may be useful in choosing optimal sites for possible long-term Moon missions.


Have not yet identified the 100 kilometer area mentioned in the above report - Zorgon

Lunar Magnetic Field: Permanent and Induced Dipole Moments
by C. T. Russell, P. J. Coleman, Jr., G. Schubert


Apollo 15 subsatellite magnetic field observations have been used to measure both the permanent and the induced lunar dipole moments. Although only an upper limit of 1.3 X 1018 gauss-cubic centimeters has been determined for the permanent dipole moment in the orbital plane, there is a significant induced dipole moment which opposes the applied field, indicating the existence of a weak lunar ionosphere.

The lunar magnetic field has been studied indirectly via the natural remanent magnetization of the returned lunar samples, and directly with magnetometers carried to the surface and placed in orbit at low altitude above the surface on the Apollo 15 and Apollo 16 subsatellites. These measurements reveal widespread lunar magnetism with scale sizes ranging up to many tens of kilometers. The origin of these fields remains a puzzle. According to one model, there existed an ancient lunar dipole field either generated by an internal dynamo, induced by a strong external field, or acquired during accretion. If this were true, then some trace of this ancient global field might still be present, and it is of some interest to attempt to detect this field.

SOURCE and Rest of Article

I really like this option... generated by an internal dynamo... However indications are that the moon has both permanent areas exhibiting strong magentic fields {or magcons] as well as fluctuating ones. Must be hell to plot orbits under these conditions. - Zorgon

From the same Source:
"In summary, there is no present-day evidence for the existence of an ancient lunar dipole field in the data of the Apollo subsatellites. Although there are substantial magnetic fields at many of the lunar landing sites and although extensive magnetic anomalies, or magcons, have been observed from lunar orbit, there is little overall order to the field. Finally, the negative induced moment implies the existence of a substantial lunar ionosphere when the moon is in the lobes of the geomagnetic tail. Thus, both orbital and surface measurements are required to deduce the ratio of the lunar permeability to that of its plasma environment. "

And this ties in nicely with the Pegasus Group's research into the electro dynamic nature of the Universe - Zorgon

Lunar Prospector
Although it was previously believed that the Moonís magnetic field was too weak to repel the charged particles of the solar wind, an intriguing magnetic anomaly on the Moonís surface has been found that can stand off the solar wind, thus creating the smallest known magnetosphere, magnetosheath and bow shock system in the Solar System. While most planets' global fields create a large encompassing magnetosphere around the entire body, the Moon contains magnetized rocks on its upper layers, some of which are magnetized strongly enough to form small dipole magnetic fields scattered on the lunar surface. These mini-magnetospheres, around 100 km in diameter (the Moon is approximately 3500 km in diameter), can stand off the solar wind locally.
Image Credit NASA

This diagram (above) shows the magnetic anomaly on the Moon which is powerful enough to "stand off" the solar wind. This is the smallest such magnetic shock front ever identified.

Of course, the process of completely mapping the lunar magnetic fields is still in progress, and many more questions can be addressed once the complete data set is analyzed. At that point, scientists will be able to investigate the existence of a core and more accurately determine its upper size limit. They can also determine the electrical conductivity and postulate about the composition of the core. In addition, mapping the direction of the magnetization, and therefore determining the orientation of the field lines at the time of magnetization, will help elucidate the origin of the lunar magnetic field. Another enigma waiting to be solved is the unexpected correlation between individual magnetic anomalies with unusual albedos markings in the antipodal zones -- the markings are lighter in color, and therefore higher in albedo. Answers to these and many other questions are anticipated as the mission develops.


NASA Lunar Prospector Mission Homepage

Reiner Gamma: The Mysterious Enigma
Image Credit: clipped from Clementine Image...USGS 


Using the high-resolution regional MAG maps, we report here a close correlation of the strongest individual crustal anomalies with the locations of unusual curvilinear albedo markings (hereafter referred to as “swirls”). This correlation is known in the case of the nearside Reiner Gamma albedo marking from limited mapping ofApollo 16 subsatelliteMAG data (3). However, the LP MAG data are more complete and
include low-altitude coverage over several of the more extensive groups of both magnetic anomalies and swirls on the lunar far side. (See image below entitled "Blue Glass")

Figure 1: The Reiner Gamma Anomaly

Image Credit:LPI

Much more extensive groups of anomalies comparable to or larger in amplitude than the Reiner Gamma anomaly were detected on the lunar far side by both the LP ER and MAG (1). These more extensive groups of anomalies are centered approximately antipodal (diametrically opposite) to young large impact basins including Imbrium, Orientale, Crisium, and Serenitatis (4). Regional maps of the Imbrium and Crisium antipode anomaly concentrations show that the strongest field maxima correlate well with the locations of prominent swirls. In the Imbrium antipode region (Figure 2), the strongest single anomaly has a smoothed amplitude of 23nT at a mean altitude of about 19 km. The anomaly peak is centered approximately on a group of swirls visible in thesouthern part of the Ingenii basin (5). An even stronger individual anomaly is present in the Crisium antipode region; it has a smoothed amplitude of 26 nT at an altitude of 24 km. Secondary anomalies with amplitudes of 18 and 16 nT are also nearby. This cluster of strong anomalies is centered approximately at 123°E, 23°S on a large group of swirls located on pre-Nectarian terrain just west of the main ejecta facies of the Orientale basin (5).


The second model(7) argues that the swirls represent exposed silicate materials whose albedos have been selectively preserved via deflection of the solar wind ion bombardment by pre-existing strong crustal
magnetic fields. According to this model, optical maturation or “spaceweathering” of exposed silicate surfaces in the inner solar system is at least partly a function of the solar wind ion bombardment.

LOL Sounds like glass making :-) The area just mentioned above is in the image below...

Figure 2: "Blue Glass" Swirls on the Farside, Mare Marginis

Image Credit: clipped from Clementine Image...USGS 



Title:  Optical Properties of Reiner Gamma Magnetic Anomaly on the Moon
Authors:  Shevchenko, V. V.
Publication: LUNAR AND PLANETARY SCIENCE XV, P. 772-773. Abstract.
Publication Date: 03/1984
Category: Moon
Origin: LPI [AN-840391%BOOKS (QB 591 A7A 1984)]
LPI Keywords: 
Bibliographic Code: 1984LPI....15..772S

Editor's note: This article is currently not available. It is interesting to note here that V. V.Shevchenko's name also appeared in an article we found about picking locations for a Lunar Base dated back to 1968!. {We will cover that in a later section} - Zorgon

Join the live discussion on Anomalies on the Moon and on Mars 
at Above Top Secret Discussion Forum

John Lear's Moon Pictures on ATS


Revealed for the First Time Color Images of the Moon from Clementine Satellite

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