The European Space Agency has published the first image obtained with MERTIS installed on the BepiColombo spacecraft. It shows variations in the surface temperature of the solar system’s first planet.
The image was taken on December 1, 2024. On this day, BepiColombo made its fifth flyby of Mercury, passing at a distance of 37,000 km from its surface. During this visit, mission specialists activated MERTIS for the first time and conducted a test survey.
The resulting MERTIS image covers most of the 1,500-kilometer-long Caloris Planitia (which is the planet’s largest crater) as well as a large volcanic plain in the Northern Hemisphere. Its resolution is 26-30 km. The brightness of the surface in the infrared range depends on its temperature and chemical composition.
The MERTIS image in particular shows the 75-kilometer-long Bashō impact crater. Previous visible light images have shown that it contains both very bright and very dark material. One suggestion is that the latter may be graphite.
What the surface of the small planet is made of is one of the many mysteries of Mercury that MERTIS is expected to solve. Data collected by the MESSENGER mission showed that it has relatively little iron, despite the planet’s anomalously large iron-nickel core. As well, although Mercury orbits close to the Sun, some chemical elements that vaporize easily are present on its surface in unusually high concentrations.
Another long-standing mystery is related to surface composition — why does the planet look so dark? At first view, the crater-covered Mercury looks like the Moon. But in reality, its surface reflects a third less light. Scientists hope that MERTIS will help answer this question as well.
Earlier we reported on the possibility of an 18-kilometer layer of diamonds hiding in the depths of Mercury.
Provided by ESA
