Mercury's shadowy North Pole revealed by M-CAM 1

The ESA's article claims to "reveal" Mercury's shadowy north pole, yet the image provides no actual insight into the pole itself, which remains shrouded in permanent darkness... The term "revealed" feels more like marketing spin than substance, as the image merely captures the general area around the pole.

This framing is reminiscent of similar oversights in planetary science, such as the perplexing case of Mars' north pole. Studies suggest a cyclical process where subsurface vapor escapes through a thinned crust during colder seasons, freezing into massive ice deposits, like those seen in the Korolev Crater. These ice layers, some over 1.2 miles thick (see the ESA Korolev Crater Study), challenge the traditional narrative of Mars' geophysical activity. Observations from missions like Mars Express and Mars Reconnaissance Orbiter reveal hints of dynamic interactions between the crust and atmosphere, yet much of this is glossed over in mainstream discussions.

Why is there a persistent pattern of incomplete or opaque presentations regarding planetary poles? The public deserves transparency and detailed interpretations, not handwaving claims. If the evidence of crustal thinning and volatile release is as compelling as the imagery suggests, why the reluctance to address it head-on???

A commitment to clarity would foster trust in scientific institutions, rather than leaving informed observers to speculate about what's being left unsaid. This is frustrating.

With labels describing the surface features: https://www.esa.int/ESA_Multimedia/Images/2025/01/Mercury_s_...

Absolutely love the ESA Like button in the article. Conveys the feeling it's designed by a flight instruments engineer rather than a social media frontend person (make sure to click it twice).

>M-CAM 1 took this long-exposure photograph of Mercury's north pole

I'm curious how this works. The dynamic range between the sunlit parts and the dark portions must be huge at that distance from the Sun. Anyone have the technical details on the camera or post processing they use to achieve this? Is it really a long exposure or is it a series of photos at different exposures stitched together?

Edit: details at the bottom seem to imply a single photo, but that "long exposure" really isn't that long

>This image of Mercury's surface was taken by M-CAM 1 [...] using an integration time of 40 milliseconds.

I was curious as to whether its north pole is always inclined away from the sun, as it could be if mercury is in synchronous rotation around the sun. It turns out that it is not: it has a 3:2 spin–orbit resonance, rotating three times for every two orbits. On the other hand, its axial tilt is small - only 0.034 degrees [1], which I suppose means that the pole is always close to the terminator - but, as the angular size of the sun as seen from mercury is always a bit over a degree [2], I think that means some fraction of the sun's disk would always be above the horizon at the north pole (unless it is in a crater.)

Update: From this map [3], the pole appears to be on the rim of the crater touching crater Tolkein on the latter's right (see ahazred8ta's comment for a link to an annotated copy of the photograph), and in the photograph, that part of the rim is illuminated.

[1] https://nssdc.gsfc.nasa.gov/planetary/factsheet/mercuryfact....

[2] Data from [1] and https://en.wikipedia.org/wiki/Sun:

   Solar radius: 7e8 M
   Mercury aphelion: 7e10 M
   Angular radius at aphelion = arctan 0.01 = 0.57 degrees.

[3] https://pubs.usgs.gov/sim/3404/sim3404_sheet2_.pdf

I would have expected a larger crater for Tolkien..