May 16, 2021
Chains of Enlightenment
Originally published September 27, 2011
south up image by Jocelyn Sérot, France
|Nubium is a relatively blaise mare, but under the right lightening a buried history becomes visible. Pitatus, with a little light streaming across its floor, is at top, and at the north end (bottom right corner) of a chain of ruins is Opelt. The ruins are defined by circular mare ridges, some with residual crater rims still visible. The chain of ruins from Opelt up to Gould and Wolf (with residual islands surrounding its south/upper side) could be old craters mostly covered by Nubium's lavas. But it is odd that these just barely preserved craters are in a line. Weren't there other impact craters in the floor of the Nubium Basin before it was flooded with lava. Well, yes, like the nearly complete mare ring just to the right of Wolf and the three or four battered ruins heading from there up towards Pitatus. Another line. Get a globe of the Moon and run your finger in a straight line from Wolf to Opelt and on for some hundreds of kilometers. You end up on the west side of the Imbrium Basin. The second line is about tangent to the west edge of Imbrium. Are these two lines actually Imbrium secondary craters, that smashed onto the surface of the Nubium Basin before it was completely flooded? But how could the second line be - it isn't radial to Imbrium? Look at the ray from Copernicus that passes between Lambert and Timocharis - that ray is roughly tangential to Copernicus.
Yesterday's LPOD: Rimless
Tomorrow's LPOD: A Better Venus