The lunar surface is a harsh landscape; a bone-dry expanse of impact-pummelled rock whose "seas" have long been known as a misnomer. The only precipitation is in the form of solar and cosmic radiation that gradually darkens the dust and corrupts the cells of any astronauts present.

Yet amidst this hostile landscape a number of safer havens exist where the lunar surface escapes much of this radiation. One such benign feature, named Reiner Gamma, lies on the moon’s Earth facing side and is marked by a 37-mile-long (60 km) bright swirl and one of the strongest magnetic fields found on the lunar surface.

“The Moon presently has no global magnetic field similar to the Earth's. The observed fields [such as that at Reiner Gamma] are caused by permanent magnetization of parts of the lunar crust,” said Lon Hood of the University of Arizona.

These isolated pockets of lunar magnetism were discovered in the early 1970’s by lunar-orbiting spacecraft and their formation is thought to be as dramatic as their appearance.

Reiner Gamma’s magnetic shield also channels the solar ions it does divert into narrow regions surrounding the feature, another boon for human exploration.

“This would concentrate solar wind hydrogen and helium-3 locally which might be beneficial to increase the efficiency of mining these for resource applications,” Hood said. Helium-3 is a light isotope of helium carried in the solar wind and is a potential fuel for efficient and non-polluting nuclear fusion. The hydrogen would also be essential to the manufacture of water for a lunar outpost.

Only a spacecraft on the surface will be able to definitively reveal the method of Reiner Gamma’s formation. Until then, future lunar orbiters such as NASA’s Lunar Reconnaissance Orbiter and India’s Chandrayaan-1 spacecraft will undertake further analysis of this unusual feature.

The photographs are a little tricky. Some of the stitches look very strange because the photos were taken at dawn and dusk respectively. Basically the angle of light changes direction across the stitch line (this is up north of Copernicus.)

To those people looking for domes.

Originally posted by Saviour Of The Real
Someone mentioned radiation and magnetic fields on the Moon? I believe Reiner Gamma is one of the "anomalies" you guys identified...

Glad you mentioned this...

These isolated pockets of lunar magnetism were discovered in the early 1970’s by lunar-orbiting spacecraft and their formation is thought to be as dramatic as their appearance.

LOL yes dramatic indeed... enough to rip a satellite right out of orbit!!

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.

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.

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"

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 sub satellites. 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.

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.

REGIONAL MAPPING OF THE LUNAR CRUSTAL MAGNETIC FIELD:
CORRELATION OF STRONG ANOMALIES WITH CURVILINEAR ALBEDO MARKINGS.

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. (Added by me:See image below entitled "Blue Glass")

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 the southern 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. SOURCE LPI 1251 PDF

Below are seismic records (seismograms) obtained by the Passive Seismic Experiment. The top two are produced when a spent Saturn IV-B casing was forced to crash on the Moon and when a LM (left behind as the CSM returns to Earth) was allowed to decay in orbit and hit the Moon. The bottom two records are of natural (and small; magnitudes of 2 or less) moonquakes from the interior.

All these records differ from those associated with terrestrial earthquakes in lacking S (secondary or shear) waves. They also last for much longer than earthquakes - up to an hour, as though the Moon were "ringing" like a bell. The bulk of the moonquakes originate from depths of 600 km or more (attributed to the seismic signals bouncing back and forth in the low velocity surface layers [ejecta blanket]). They tend to occur in swarms associated both with preferred spatial locations and specific time intervals (probably accounted for by stresses induced by terrestrial tidal forces).

Seismometers at Apollo 12, 14, 15, and 16 continued to operate for years, providing a wealth of data about the Moon's interior. One model for that interior is shown in this diagram:

Note the two velocity discontinuities at about 20 and 60 km. Velocities within this interval are consistent with anorthosites. The higher velocities deeper than 60 km are associated with a proposed pyroxene-olivine upper mantle. Velocities between 4 and 20 km are indicative of a fractured basaltic flow sequence responding to load pressure. The shallow velocities (lower left inset) are attributed to the lunar ejecta blanket units discussed on the preceding page, overlain by comminuted regolith.

There are at least four different kinds of moonquakes: (1) deep moonquakes about 700 km below the surface, probably caused by tides; (2) vibrations from the impact of meteorites; (3) thermal quakes caused by the expansion of the frigid crust when first illuminated by the morning sun after two weeks of deep-freeze lunar night; and (4) shallow moonquakes only 20 or 30 kilometers below the surface.

The first three were generally mild and harmless. Shallow moonquakes on the other hand were doozies. Between 1972 and 1977, the Apollo seismic network saw twenty-eight of them; a few "registered up to 5.5 on the Richter scale," says Neal. A magnitude 5 quake on Earth is energetic enough to move heavy furniture and crack plaster.

Furthermore, shallow moonquakes lasted a remarkably long time. Once they got going, all continued more than 10 minutes. "The moon was ringing like a bell," Neal says.

On Earth, vibrations from quakes usually die away in only half a minute. The reason has to do with chemical weathering, Neal explains: "Water weakens stone, expanding the structure of different minerals. When energy propagates across such a compressible structure, it acts like a foam sponge—it deadens the vibrations." Even the biggest earthquakes stop shaking in less than 2 minutes.