Abstract
THE question of the nature and temperature of the lunar surface has recently acquired a new interest since microwave radar observations of the temperature have become possible. Twenty years ago Pettit, working in the infra-red, measured the fall of surface temperature during a lunar eclipse, and from this information Epstein1 deduced that most of the surface is covered with a material the thermal properties of which are comparable with those of pumice. If K, ρ and c are the thermal conductivity, density and specific heat of the lunar material (assumed to be constant), t0 is the duration of penumbra, and A is the insolation before the eclipse, he gave the formula for the fall of temperature up to time t after the beginning of penumbra, and from the observations deduced (Kρc)−½ = 120, the units being C.G.S. and °C. The source of this formula was not stated, but it is, in fact, that for the surface temperature of a semi-infinite solid from which heat is extracted at the rate At/t0 per unit time per unit area. This is equivalent to assuming that the surface loses heat during the eclipse at a rate proportional to the fourth power of its initial temperature, instead of to the fourth power of its actual temperature, and since the temperature-range involved is from 370° K. to about 200° K., formula (1) will give values which are far too large. To get an accurate result, the non-linear equations must be studied numerically: this has been done recently by Wesselink2, who finds a value (Kρc)−½ = 920, and shows that this value is consistent with dust at low pressures (he does not point out the incorrectness of Epstein's calculation, and, indeed, states that their results agree, which by a coincidence they do, though, in fact, they are in different units).
Similar content being viewed by others
Article PDF
References
Epstein, P., Phys. Rev., 33, 269 (1929).
Wesselink, A. J., Bull. Astro. Inst. Netherlands, 10, 351 (1948).
Piddington, J. H., and Minnett, H. C., Aust. J. Sci. Res., 2, 63 (1949).
Pettit, E., Astrophys. J., 91, 408 (1940).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
JAEGER, J., HARPER, A. Nature of the Surface of the Moon. Nature 166, 1026 (1950). https://doi.org/10.1038/1661026a0
Issue Date:
DOI: https://doi.org/10.1038/1661026a0
This article is cited by
-
The Lunar Reconnaissance Orbiter Diviner Lunar Radiometer Experiment
Space Science Reviews (2010)
-
Infrared observations of the moon and their interpretation
The Moon (1972)
-
Surface Temperatures of the Galilean Satellites of Jupiter
Nature (1968)
-
Sub-surface Temperatures on the Moon
Nature (1959)
-
On the heat budget of the moon and the surface temperature variation during a lunar eclipse
Geofisica Pura e Applicata (1951)
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.