Infrared Images of Tycho on Dark Moon

Science  03 Mar 1967:
Vol. 155, Issue 3766, pp. 1098-1100
DOI: 10.1126/science.155.3766.1098


Infrared images of the thermal anomaly associated with the lunar crater Tycho were obtained during the lunar night after Tycho had ceased to be illuminated by the Suin for as long as 97 hours. In agreement with results of previous studies, these measurements show that the crater is warmer than its surroundings during the lunar night, and that the temperature of the thermal anomaly gradually decreases with time, being no longer detectable after new moon. This work provides strong evidence that the steeper crater walls facing the Sun before local sunset are warmer throughout the cooling phase, and that the Tycho anomaly is thus produced by solar, rather than internal, heat.