December 2, 2021
Originally published January 20, 2012
image by Antonio Lasala Garcia, Morata de Jalón (Zaragoza, Spain)
The Sirsalis Rille is fascinating because of its great length and strong magnetic field, but I think that what we see here is pretty remarkable too. I refer to where the rille drops down into the crater De Vico A and then climbs up its wall. It looks like it was draped across the landscape, like a ray. But it is driven by forces from below, apparently a vertical sheet of magma that also probably travelled laterally and fed lava to Oceanus Procellarum. The rille had to be lower on the crater floor than on its rim since it can't float. Once the Sirsalis Rille exits De Vico A it crosses the floor of a large unnamed crater where it makes a big bend. The reason for the bend is completely mysterious to me, but one thing that is clear is a series of rilles that appear to start at the Sirsalis one and head toward Darwin, where one strong rille diagonally crosses the floor. Rilles seem to be like cats; they do whatever they want to do. At least that is the way it seems when we can't figure out the forces that guide them.
2011-10-10, 19h30m to 19h32m TU. Newton 254 F28 + DMK 21au04.AS + R25 filter
Rükl plate 50
Yesterday's LPOD: Northern Wow
Tomorrow's LPOD: French Moon