An article published in the journal “Icarus” describes a study on the water ice existing in the shadow of several craters of the planet Mercury that aimed to estimate tis amount, which could be much higher than that predicted with glaciers tens of meters thick. The estimates are still approximate and there are still a number of hypotheses about the origin of that water.
In recent years, the data collected by the NASA’s MESSENGER (MErcury Surface, Space Environment, Geochemistry, and Ranging) space probe made it possible to obtain evidence of the existence of water ice in the polar regions, craters permanently shade. Finally, in October 2014 photos of the ice existing in some craters were presented. It was an important moment in the research on the planet Mercury but they went on to better understand the characteristics of these ice.
In this new research, conducted by a team of scientists led by Vincent Eke of the British Durham University, developed computer simulations using elevation models to estimate the thickness of the ice in 663 craters of Mercury in the region around the planet’s north pole. In particular, they used data collected by the Mercury Laser Altimeter (MLA), one of the MESSENGER space probe’s instruments with results very different than the previous estimates.
In the past, research of this type were based on different types of detections and indicated that the water ice deposits had a thickness of at least one or two meters. This new research suggests that the thickness may be 50 ± 35 meters, meaning that it’s much higher than previously thought. Those are very rough estimates but they start at a minimum of 15 meters to a maximum of 85 meters.
The origin of that ice remains a source of debate. Comets are by far the leading candidate but which ones? There are different families of comets, some born in the Oort cloud, the outermost area of the solar system of which we actually know almost nothing, others born in the Kuiper belt, the area beyond Neptune’s orbit yet close compared to the Oort cloud.
According to Vincent Eke the results regarding the ice thickness suggest that it was brought by comets from the Kuiper belt because they are more common. This is a deduction that needs to be verified, starting with the confirmation of the results of this research and more accurate data on the distribution of ice in the craters. The BepiColombo mission by ESA with the cooperation of JAXA in the next decade should provide those answers.