Back in May when I posted an image of the Lunar Appeninne Mountains
https://nikongear.net/revival/index.php?topic=1867.msg199591#msg199591 where I stated that "The Apennine mountains are >40,000 meters high". At the time I missed a discrete PM from Armando where he questioned if that was correct. When I now after spotting his message tried to Google the "The highest mountain on the moon" I found that Mons Huygens that is part of Montes Apenninus is listed at 18,046 ft/5500 m,
https://lsc.org/news-and-social/news/the-moon-has-craters-but-did-you-know-it-has-mountains-too. Thanks to Armando for bringing this to my attention!
As I gave no link in my previous post, I now just could not figure out where this number came from. The same article also states that even though "it is Moon’s highest mountain, Mons Huygens isn’t the Moon’s highest point. That would be the Selenean summit, which is 35,387 ft above the Moon’s center". That is 10786m, so far off from my previous number and I started wondering if that was due to my brain hallucinating like an AI chatboot!
But then finally I found the article my 40,000 m number had been based on,
https://en.wikipedia.org/wiki/List_of_mountains_on_the_Moon. So I was not hallucinating after all, Montes Apeninnus is listed at 401000 m. (That is one zero more than I reported, so my original number was not correctly reported). What goes on here is different ways of defining the zero elevation level. The wiki article mention that "Mountains on the Moon have heights and elevations/altitudes defined relative to various vertical datums (referring to the lunoid), each in turn defined relative to the center of mass (CoM) of the Moon." Further down "... This is because the Moon has mass asymmetries: the highest point, located on the far side of the Moon, is approximately 6,500 meters higher than Mons Huygens (usually listed as the tallest mountain)." So I missed that fact that this list is just numbers listed relative to a defined datum and not actual height of the mountain above a wide area of lower surroundings.
Of course figuring out anything about the moon has historically been difficult.
Here is a sequence of two naturally occurring renditions of the full moon as a folded flat disc from a flight from Fairbanks to Seattle in July. I had a middle row seat in the plane, but that did not prevent me from using the 300PF on the Z8, which as usual was in my personal item under the seat in front to me. There were boundary layers in the atmosphere on top of clouds that created the optical illusion that clearly demonstrated the difficulty of measuring altitudes on the moon.
