Traces of volatile substances: Mercury is probably not a dead planet after all

The innermost planet of the solar system is apparently not as dead as previously assumed, and is quite geologically active instead. This is suggested by a study of about 100,000 satellite images from NASA's Messenger probe, which has now been presented. Numerous bright streaks were discovered in the images, "which are presumably caused by the outgassing of volatile substances from the planet's interior," summarizes the University of Bern. Because these so-called "lineae" predominantly occur on the sun-facing side in particularly exposed regions, solar radiation likely plays an important role in their formation, explain the researchers.

Waiting for BepiColombo

The research group around Valentin Bickel from the University of Bern now explains that the "lineae" were known for a long time, but a systematic analysis had not yet taken place. Only a handful of them were known. To enable this now, the team first created a complete inventory of all 400 found lines using machine learning methods. Only then could they find the patterns presented now in their distribution and speculate about the cause. It was shown that the streaks primarily occur on sun-facing slopes of young impact craters.

The group believes that their finding indicates that volatile substances are released from the planet's interior when it is hit by objects. This could be sulfur or other light elements. This suggests that Mercury is more geologically active than assumed. The image of a "dead, dry, and boring planet" must apparently be adjusted to include this dynamic. This is also important for future missions. First, the research group hopes that observations from the ESA probe BepiColombo, which will reach Mercury at the end of the year, will confirm their analysis and provide further insights. Their work is presented in the journal Nature Communications Earth & Environment.

(mho)