Abstract
The electrical conductivity of the lunar interior has been determined from magnetic field step transients measured on the lunar dark side. The simplest model which best fits the data is a spherically symmetric three layer model having a nonconducting outer crust of radial thickness ≈ 0.03R moon; an intermediate layer of thicknessΔR≈0.37R moon, with electrical conductivityσ 1 ≈ 3.5 × 10−4 mhos/m; and an inner core of radiusR 2 ≈ 0.6R m with conductivityσ 2 ≈ 10−2 mhos/m. Temperatures calculated from these conductivities in the three regions for an example of an olivine Moon are as follows: crust, < 440 K; intermediate layer, ≈ 890 K; and core, ≈ 1240 K. The whole-moon relative permeability has been calculated from the measurements to beμ/μ 0 = 1.03 ± 0.13. Remanent magnetic fields at the landing sites are 38 ± 3γ at Apollo 12, 43 ± 6 and 103 ± 5γ at two Apollo 14 sites separated by 1.1 km, and 6 ± 4γ at the Apollo 15 site. Measurements show that the 38γ remanent field at the Apollo 12 site is compressed to 54γ by a solar wind pressure increase of 7 × 10−8 dynes/cm2.
Article PDF
Similar content being viewed by others
References
Barnes, A., Cassen, P., Mihalov, J. D., and Eviatar, A.: 1971,Science 172, 716–718.
Dyal, P. and Parkin, C. W.: 1971a, inProceedings of the Second Lunar Science Conference 3, (ed. by A. A. Levinson), MIT Press, Cambridge, Mass., pp. 2391–2413.
Dyal, P. and Parkin, C. W.: 1971b,J. Geophys. Res. 76, 5947–5969.
Dyal, P., Parkin, C. W., and Sonett, C. P.: 1970a,IEEE Trans. on Geoscience Electronics GE-8, 203–215.
Dyal, P., Parkin, C. W., and Sonett, C. P.: 1970b, ‘Lunar Surface Magnetometer Experiment’, in Apollo 12 Preliminary Science Report, NASA SP-235, pp. 55–73.
Dyal, P., Parkin, C. W., Sonett, C. P., DuBois, R. L., and Simmons, G.: 1971, ‘Lunar Portable Magnetometer Experiment’, inApollo 14 Preliminary Science Report, NASA SP-272, pp. 227–237.
England, A. W., Simmons, G., and Strangway, D.: 1968,J. Geophys. Res. 73, 3219–3226.
Geyger, W. A.: 1964,Nonlinear-Magnetic Control Devices, McGraw-Hill, New York.
Gordon, D. E., Lundsten, R. H., and Chiarodo, R. A.: 1965,IEEE Trans. on Magnetics,MAG-1, 330–337.
Helsley, C. E.: 1970, inProceedings of the Apollo 11 Lunar Science Conference, (ed. by A. A. Levinson)3, Pergamon, New York, pp. 2213–2219.
Helsley, C. E.: 1971, inProceedings of the Second Lunar Science Conference 3 (ed. by A. A. Levinson), MIT Press, Cambridge, Mass., pp. 2485–2490.
Jackson, J. D.: 1962,Classical Electrodynamics, John Wiley, New York, 163.
Keller, G. V. and Frischknecht, F. C.: 1966,Electrical Methods in Geophysical Prospecting, Pergamon, New York.
Kopal, Z.: 1969,The Moon, D. Reidel, Dordrecht, The Netherlands.
Nagata, Takesi: 1970, ‘Electrical Conductivity and Age of the Moon’, Paper M. 14, Thirteenth Planetary Meeting, COSPAR, Leningrad, U.S.S.R.
Runcorn, S. K., Collinson, D. W., O'Reilly, W., Battey, M. H., Stephenson, A. A., Jones, J. M., Manson, A. J., and Readman, P. W.: 1970,Proceedings of Apollo 11 Lunar Science Conference 3, Pergamon, New York, pp. 2369–2387.
Sill, W. R. and Blank, J. L.: 1970,J. Geophys. Res. 72, 501.
Smythe, W. R.: 1950,Static and Dynamic Electricity, McGraw-Hill, New York.
Snyder, C. W., Clay, D. R., and Neugebauer, M.: 1970, inApollo 12 Preliminary Science Report, NASA SP-235, pp. 75–81.
Sonett, C. P., Colburn, D. S., Currie, R. G., and Mihalov, J. D.: 1967, inPhysics of the Magnetosphere (ed. by R. L. Carovillano, J. F. McClay, and H. R. Radoski), D. Reidel, Dordrecht, The Netherlands.
Sonett, C. P., Schubert, G., Smith, B. F., Schwartz, K., and Colburn, D. S.: 1971, inProceedings of the Second Lunar Science Conference 3, (ed. by A. A. Levinson), MIT Press, Cambridge, Mass., pp. 2415–2431.
Urey, H. C. and MacDonald, G. J. F.: 1970, inPhysics and Astronomy of the Moon (ed. by Z. Kopal), Academic Press, New York.
Author information
Authors and Affiliations
Additional information
National Research Council Postdoctoral Associate.
Rights and permissions
About this article
Cite this article
Dyal, P., Parkin, C.W. Lunar properties from transient and steady magnetic field measurements. The Moon 4, 63–87 (1972). https://doi.org/10.1007/BF00562915
Issue Date:
DOI: https://doi.org/10.1007/BF00562915