Does this image show actual EDM cratering or spark erosion cratering happening on comet 67P?
Or are the jets that you can see in the brighter right side image just an electrochemical event that does not help to create this and the craters (chain) beside it?
An active pit spotted by Rosetta on comet 67P. Enhancing the contrast (right panel) shows fine structures in the shadow of the pit, interpreted as fine jets of gas.
"The images of the goosebump terrain in the pits are suggesting that the nucleus is indeed a rubble pile but all the 'rubble' is about the same size," he said. "This is consistent with current ideas about how accretion of comets worked in the early solar system."
Goosebumps, cliffs, basins, pits: What Rosetta has seen so far
The rubble or boulders in the bottom of the pits/craters due to where the rocky surface material of comet 67P/Churyumov-Gerasimenko has been eroded away and the bits fall down to the bottom? Perhaps showing how and why you do get boulders or rocks in holes or craters?
Or the birth of rock?
Comet 67P - active EDM cratering/pits?
Would geology describe these pits as doline, sinkhole, collapse caves if they were not on a comet? How were they formed? How are they also found in cliffs?
In the Seth region, extending around the neck from one end of Hapi, we observe a closely packed system of well-defined pits and depressions with remarkably flat floors. The walls of these features show linear structures that are parallel to their floors and extend laterally hundreds of meters, indicating a consolidated structure, but they also exhibit vertical striations. Some of these quasi-circular pits are minor sources of activity. They are similarly seen in cliffs and are possibly erosion features related to activity. They range from 50 to 300 m in diameter and 10 to 200 m in depth. We find other pits everywhere on the nucleus.
Such pits have been observed on comets 81P/Wild 2 and 9P/Tempel 1, and those were interpreted as activity-related features rather than impact craters because of their flat size distribution.
The pits on the nucleus of 67P share a similar morphology, although the active ones tend to have a depth/diameter ratio close to 1, whereas the inactive pits are much shallower, seemingly filled with fine dust and multiple boulders. It is not clear whether these pits are inactive or whether they will “wake up” when they start receiving more illumination.
On the nucleus structure and activity of comet 67P/Churyumov-Gerasimenko - Nuclear properties and geomorphology
The active pits/craters on comet 67P strangely have ratio? Not lots that are deep compared to their diameter? Is this due to electric discharging at the higher points of the surface?