Comments on: Meanwhile, closer to home at Ceres https://habitablezone.com/2015/09/10/meanwhile-closer-to-home-at-ceres/ Thu, 09 Apr 2026 15:15:13 -0700 hourly 1 http://wordpress.org/?v=3.3.1 By: ER https://habitablezone.com/2015/09/10/meanwhile-closer-to-home-at-ceres/#comment-32766 ER Sat, 12 Sep 2015 03:28:03 +0000 https://www.habitablezone.com/?p=50479#comment-32766 Underground nuclear tests create great caverns beneath the surface, which later may cave in under the weight of the surface material. A similar effect occurs with meteoroid impacts. The crater is not created by the mechanics of impact. The projectile penetrates deep below the surface, the kinetic energy of the impactor converts it to a plasma which may either explode, ejecting material from the crater, or create a collapsing subterranean cavern similar to the underground nuke I described above. This is why impact craters are always circular, never elliptical, even though the impactor may have originally struck the crust at a grazing angle. Underground nuclear tests create great caverns beneath the surface, which later may cave in under the weight of the surface material. A similar effect occurs with meteoroid impacts. The crater is not created by the mechanics of impact. The projectile penetrates deep below the surface, the kinetic energy of the impactor converts it to a plasma which may either explode, ejecting material from the crater, or create a collapsing subterranean cavern similar to the underground nuke I described above.

This is why impact craters are always circular, never elliptical, even though the impactor may have originally struck the crust at a grazing angle.

]]> By: podrock https://habitablezone.com/2015/09/10/meanwhile-closer-to-home-at-ceres/#comment-32763 podrock Sat, 12 Sep 2015 00:22:28 +0000 https://www.habitablezone.com/?p=50479#comment-32763 Ductile Solid Migration Tectonics (DSMT...I just made that up...) requires an overburden structural weakness. In the case of Gulf Coast Salt Domes, it's an intersection of faults. For the Canyonlands, it's the canyon itself; or, as earlier discussed, an impact in a favorable stratigraphy. Such is the case, I suggest, on Ceres. An impact over a localized deposit of a solid ductile material at the proper depth. In some ways, it is this postulated heterogeneous stratigraphy that has me scratching my head. Ductile Solid Migration Tectonics (DSMT…I just made that up…) requires an overburden structural weakness. In the case of Gulf Coast Salt Domes, it’s an intersection of faults. For the Canyonlands, it’s the canyon itself; or, as earlier discussed, an impact in a favorable stratigraphy. Such is the case, I suggest, on Ceres. An impact over a localized deposit of a solid ductile material at the proper depth.

In some ways, it is this postulated heterogeneous stratigraphy that has me scratching my head.

]]> By: Robert https://habitablezone.com/2015/09/10/meanwhile-closer-to-home-at-ceres/#comment-32762 Robert Fri, 11 Sep 2015 21:57:39 +0000 https://www.habitablezone.com/?p=50479#comment-32762 Thanks for reminding me of a couple of blind spots I need to allow for. One is, obviously, assuming all craters are impact craters, and not seeing the signs of subsidence. So obvious with the blinders removed. And much more interesting, for the rich story it suggests of "ice or salt tectonics at play". A wonderful turn of phrase for the imagery it evokes. And thus I should avoid unconscious assumptions about a solid surface and what lies beneath. These little planetoids ought to be lumpier than my familiar large terrestrial home, and who knows what you might turn up scratching the surface at any particular spot. Fascinating place, this solar system. Thanks for reminding me of a couple of blind spots I need to allow for. One is, obviously, assuming all craters are impact craters, and not seeing the signs of subsidence. So obvious with the blinders removed. And much more interesting, for the rich story it suggests of “ice or salt tectonics at play”. A wonderful turn of phrase for the imagery it evokes. And thus I should avoid unconscious assumptions about a solid surface and what lies beneath. These little planetoids ought to be lumpier than my familiar large terrestrial home, and who knows what you might turn up scratching the surface at any particular spot.

Fascinating place, this solar system.

]]> By: podrock https://habitablezone.com/2015/09/10/meanwhile-closer-to-home-at-ceres/#comment-32761 podrock Fri, 11 Sep 2015 17:43:19 +0000 https://www.habitablezone.com/?p=50479#comment-32761 There were hints before with the old images, but now the radial fractures in the crater are quite apparent. There is a nice example of fractures from the center to bottom of the scene. Another group exists between the center and the spots to the "northeast". To my eye, these look like the sorts of fractures that develop when material is being removed from below. Also, note well the hummocky terrain in the bottom of the crater. Material is moving down the slopes and from more than just landslides. In my opinion, the crater floor is collapsing. Strong evidence that there is either ice or salt tectonics at play. Or both. There were hints before with the old images, but now the radial fractures in the crater are quite apparent. There is a nice example of fractures from the center to bottom of the scene. Another group exists between the center and the spots to the “northeast”. To my eye, these look like the sorts of fractures that develop when material is being removed from below. Also, note well the hummocky terrain in the bottom of the crater. Material is moving down the slopes and from more than just landslides. In my opinion, the crater floor is collapsing. Strong evidence that there is either ice or salt tectonics at play. Or both.

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