Vernadsky Institute and Indian colleagues explain differing crater depths at the Moon's poles
Satellite-image analysis shows similar ice amounts in craters at both poles; the authors attribute the depth difference to different surface histories.
Specialists at the Vernadsky Institute of Geochemistry and Analytical Chemistry of the Russian Academy of Sciences (GEOKHI) and their Indian colleagues have proposed an explanation for why craters at the Moon's North Pole are deeper in relative terms than those at the South Pole. According to the Russian Ministry of Science and Higher Education, the work was published in The Planetary Science Journal; this is reported by МК (наука) mk.ru
МК (наука)mk.ruOpen source ↗. The authors link the difference to different geological processes in the polar regions of the satellite.
Ice does not explain the difference
Earlier, the difference in relative depths was attributed to different degrees of water-ice filling in the craters. A more comprehensive analysis of lunar craters, studied from satellite images, showed that the amount of ice in southern and northern craters is approximately the same. The authors therefore focused on the porosity of the material in which the craters formed, and on possible changes to the craters after their formation.
According to Alexander Bazilevsky, chief researcher at the GEOKHI laboratory of comparative planetology, the relative depths of lunar craters depend only weakly on whether they contain ice.
Different surface histories
The authors believe the Moon's northern polar region underwent large-scale resurfacing. Older, smaller craters were buried by ejecta from younger ones. As a result, the crater population there consists of morphologically fresher forms with greater relative depth mk.ru
МК (наука)mk.ruOpen source ↗.
In the southern polar region, the authors say, craters underwent gradual degradation without large-scale resurfacing.
Bazilevsky noted that if the craters were shallower because they were filled with ice, ice extraction would have been attempted specifically at the South Pole. In his words, it now turns out that for studying ice it is worth going to the Moon's South and North Poles equally.
