Title of article :
Why do we see the man in the Moon?
Author/Authors :
Aharonson، نويسنده , , Oded and Goldreich، نويسنده , , Peter and Sari، نويسنده , , Re’em، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2012
Pages :
3
From page :
241
To page :
243
Abstract :
Numerical simulations and analysis show that the Moon locks into resonance with a statistical preference of facing either the current near-side or far-side toward Earth. The near-side is largely covered by dense, topographically low, dark mare basalts, the pattern of which to some, resembles the image of a man’s face. Although the Moon is locked in this configuration at present, the opposite one, with the current far-side facing Earth, is of lower potential energy and hence might be naively expected. Instead, we find that the probability of selecting each configuration depends upon the ratio of the asymmetry of the potential energy maxima, dominated by the octupole moment of the Moon, to the energy dissipated per tidal cycle within the Moon. If this ratio is small, the two configurations are equally likely. Otherwise, interesting dynamical behavior ensues. In the Moon’s present orbit, with the best-estimated geophysical parameters and dissipation parameter Q = 35, trapping into the current higher-energy configuration is preferred. With Q = 100 in analogy with the solid Earth, the current configuration is nearly certain. The ratio of energies and corresponding probabilities were different in the past. Relative crater counts on the leading and trailing faces indicate an impact may have unlocked the Moon before it settled into the present configuration. Our analysis constrains the geophysical parameters at the time of the last such event.
Keywords :
moon , satellites , interior , Dynamics , moon
Journal title :
Icarus
Serial Year :
2012
Journal title :
Icarus
Record number :
2378996
Link To Document :
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