Possible fossil lunar magnetism inferred from satellite data

Magnetization of selected nonmare areas, principally on the moon's far side, is inferred from positive disturbances in the magnitude of the magnetic field exterior to the magnetic signature of the lunar cavity observed in magnetometer data from the lunar orbiter Explorer 35. A less favored model for the field perturbations involves variations in the thickness of the low-conductivity crustal layer of the moon.     

Permanent lunar surface magnetism and its deflection of the solar wind

Magnetic compressions intermittently observed outside the lunar wake in the solar wind may be limb shocks caused by the presence of local regions of permanent magnetism on the lunar limb. Observable compression would be due to regions of length scale (radius) at least as great as several tens of kilometers and field strength greater, similar 10 gammas. Thousands of such regions might exist on the lunar surface. The steady magnetic field measured at the Apollo 12 site probably has length scale less, similar 10 kilometers and probably does not produce an observable limb shock.     

Gravitational inconsistency in the lunar theory: numerical determination

Preliminary numerical integrations of the lunar motion indicate that defects in the lunar ephemeris, due to omissions in the revised Brown lunar theory, produce errors of the order of several hundred meters in the coordinates at certain times. Such errors are large enough to affect adversely analyses of data from spacecraft, as well as determination of ephemeris time. Distinct planetary periodicities seem to appear in the residuals.     

Gravitational inconsistency in the lunar theory: confirmation by radio tracking

When range and Doppler observations of space probes near or on Moon are reduced by use of a lunar ephemeris calculated from the Brown lunar theory, residuals as large as 440 meters in position and 1.5 millimeters per second in velocity are observed. When the calculations are repeated with use of LE 5, the integrated lunar ephemeris described (1), the residuals are greatly reduced.     

A long-lived lunar core dynamo

Paleomagnetic measurements indicate that a core dynamo probably existed on the Moon 4.2 billion years ago. However, the subsequent history of the lunar core dynamo is unknown. Here we report paleomagnetic, petrologic, and (40)Ar/(39)Ar thermochronometry measurements on the 3.7-billion-year-old mare basalt sample 10020. This sample contains a high-coercivity magnetization acquired in a stable field of at least ~12 microteslas. These data extend the known lifetime of the lunar dynamo by 500 million years. Such a long-lived lunar dynamo probably required a power source other than thermochemical convection from secular cooling of the lunar interior. The inferred strong intensity of the lunar paleofield presents a challenge to current dynamo theory.     

Laser-selective demagnetization: a new technique in paleomagnetism and rock magnetism

Laser-selective demagnetization (LSD) enables the determination of the magnetic moment associated with individual mineral grains in thin sections of rock. Small volumes can be demagnetize with laser pulses directed through the optics of a microscope, permitting resolution of remanence components in individual mineral grains. LSD of mafic granulite samples revealed two paleomagnetic directional components of opposite polarity: one resided in coarse magnetite, the other in ilmenohematite-hemoilmenite exsolution intergrowths and fine magnetite indusions in clinopyroxene. These directions are consistent with those inferred from bulk demagnetization techniques, but LSD permits direct identification of the remanence carriers. The ability to discriminate magnetization components in different generations of a single mineral and to define intergrain magnetic moment distributions are significant advantages of LSD.     

Cordierite-spinel troctolite, a new magnesium-rich lithology from the lunar highlands

A clast of spinel troctolite containing 8 percent cordierite (Mg(2)Al(4)Si(5)O(18)) has been identified among the constituents of Apollo 15 regolith breccia 15295. The cordierite and associated anorthite, forsteritic olivine, and pleonaste spinel represent a new, Mg-rich lunar highlands lithology that formed by metamorphism of an igneous spinel cumulate. The cordierite-forsterite pair in the assemblage is stable at a maximum pressure of 2.5 kilobars, equivalent to a depth of 50 kilometers, or 10 kilometers above the lunar crust-mantle boundary. The occurrence of the clast indicates that spinel cumulates are a more important constituent of the lower lunar crust than has been recognized. The rarity of cordierite-spinel troctolite among lunar rock samples suggests that it is excavated only by large impact events, such as the one that formed the adjacent Imbrium Basin.     

A high-pressure structure in curium linked to magnetism

Curium lies at the center of the actinide series and has a half-filled shell with seven 5f electrons spatially residing inside its radon core. As a function of pressure, curium exhibits five different crystallographic phases up to 100 gigapascals, of which all but one are also found in the preceding element, americium. We describe here a structure in curium, Cm III, with monoclinic symmetry, space group C2/c, found at intermediate pressures (between 37 and 56 gigapascals). Ab initio electronic structure calculations agree with the observed sequence of structures and establish that it is the spin polarization of curium's 5f electrons that stabilizes Cm III. The results reveal that curium is one of a few elements that has a lattice structure stabilized by magnetism.     

Bistatic-radar detection of lunar scattering centers with lunar orbiter I

Continuous-wave signals transmitted from Lunar Orbiter I have been received on Earth after they have been reflected from the surface of the moon. The frequency spectrum of the reflected signals is used to locate discrete, heterogeneous, scattering centers on the lunar surface. The scattering centers are probably distinguished from the surrounding terrain by a higher surface reflectivity. Continuous-wave bistatic radar could provide an important new method for the study and mapping of planetary surfaces.     

Protein A磁珠检测朊病毒方法的建立

建立Protein A磁珠法检测朊病毒,将朊病毒抗体IH2包被后的Protein A磁珠与蛋白酶K消化过的攻毒小鼠脑组织匀浆液混合,经免疫沉淀缓冲液温和洗脱杂蛋白,再经0.2M甘氨酸将目的蛋白洗脱并且利用聚丙酰胺凝胶电泳检测。通过聚丙酰胺凝胶电泳检测出25KD的目的蛋白带,经与正常未消化的朊蛋白条带相比较,证实检测出朊病毒。Protein A磁珠具有高效特异的与抗体IgG结合的特点,与多克隆抗体混合后可有效结合IgG。该方法较免疫组织化学和Western-blot技术简便快速,且磁珠可以回收再使用,使成本低廉。     

Thermoluminescence of lunar samples

Appreciable natural thermoluminescence with glow curve peaks at about 350 degrees centigrade for lunar fines and breccias and above 400 degrees centigrade for crystalline rocks has been recognized in lunar samples. Plagioclase has been identified as the principal carrier of thermoluminescence, and the diference in peak temperatures indicates compositional or structural differences between the feldspars of the different rock types. The present thermoluminescence in the lunar samples is probably the result of a dynamic equilibrium between acquisition from radiation and loss in the lunar thermal environment. A progressive change in the glow curves of core samples with depth below the surface suggests the use of thermoluminescence disequilibrium to detect surfaces buried by recent surface activity, and it also indicates that the lunar diurnal temperature variation penetrates to at least 10.5 centimeters.     

Mechanism of lunar polarization

A theoretical model to explain the negative polarization of moonlight at small lunar phase angles is developed. The model is based on the polarization of light in the diffraction region bordering the geometric shadow of an opaque dielectric obstacle.     

Viscosity of lunar lavas

The viscosity of a synthetic silicate liquid with the composition of a lunar rock has been determined experimentally and found to be lower than that of any previously studied volcanic rock on earth. Course Crystallinity can be a feature of rapidly cooled surface lavas.     

A search for far-ultraviolet emissions from the lunar atmosphere

An ultraviolet spectrometer aboard the Apollo 17 orbiting spacecraft attempted to measure ultraviolet emissions from the lunar atmosphere. The only emissions observed were from a transient atmosphere introduced by the lunar landing engine. The absence of atomic hydrogen implies that solar wind protons are converted to hydrogen molecules at the lunar surface.