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Ceres High Altitude Mapping Orbit (HAMO), Late summer through fall 2015
Yadgar
post Aug 26 2015, 08:51 AM
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Hi(gh)!

Is it just me or does the mountain in fact look like an exact negative of the crater, rotated by 90 degrees?

See you in Khyberspace!

Yadgar
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hendric
post Aug 26 2015, 09:55 PM
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If it was a pingo, how did it end up starting there instead of inside the (presumably) weaker crater floor to the south? It does look like it is at the intersection of a couple of valleys, so maybe those allowed deeper cracks to reach down, far enough away from the crater? I am not 100% on the crater being older than the mountain - the slopes on both show no craters, and interior of both don't qualitatively seem much different.

The horizontal banding on the slopes is what surprises me. Are those real layers or some kind of side effect of a talus at angle of repose? In either case, none of the nearby craters have horizontal banding, just typical vertical mass-wasting bands.

Definitely a head scratcher!


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HSchirmer
post Aug 26 2015, 10:04 PM
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QUOTE (Yadgar @ Aug 26 2015, 08:51 AM) *
Hi(gh)!

Is it just me or does the mountain in fact look like an exact negative of the crater, rotated by 90 degrees?

See you in Khyberspace!

Yadgar


Yes, I noticed the same thing.
The "Lonely Mountain" bears a striking resemblance to the adjacent crater.
It looks like a giant golf divot.
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antipode
post Aug 26 2015, 10:36 PM
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I wonder if high resolution mapping might not eventually find more of these 'things', albeit at smaller scale.

It would be very strange if there truly was only 1.

P
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Habukaz
post Aug 27 2015, 09:59 AM
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That, or older ones that have been eroded almost beyond recognition. I can only imagine that a direct hit on a feature like that with a sizeable impactor could do some serious damage (or destroy it completely).


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Bill Harris
post Aug 27 2015, 10:03 AM
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QUOTE (hendric)
Definitely a head scratcher!


Yess!!! That is a good decriptor-- the closer we look, the odder it looks back at us. As I have noted with some of the Rosetta-features, it looks almost M.C. Escher-esque. wacko.gif

My preliminary take on it is that it is a "mud volcano", a deposit driven by a hydrothermal vent composed of entrained detritus and residual salts. And much akin to the Occator Spot5, and the other large spots and the many many small spots scattered about. These spots will prove to be a major feature (and enigma) of Ceres.

Note, for example, the "small' 2000-meter diameter light-toned spot about 13000 meters to the southwest (to the right on the image-view) of "Tall Mtn". It was barely noticeable on the Survey Orbit images but is somewhat prominent on the initial HAMO image and who knows about future views.

--Bill


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Habukaz
post Aug 27 2015, 10:27 AM
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By the way, I just realised that Gaue crater is similar in size (84 km) to Occator (90 km), so to get an idea of what Occator will look like to us shortly, take a look at the image of Gaue.

As far as I can see, we've also been promised a fresh HAMO image later today.


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HSchirmer
post Aug 27 2015, 01:06 PM
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QUOTE (Bill Harris @ Aug 27 2015, 11:03 AM) *
Yess!!! That is a good decriptor-- the closer we look, the odder it looks back at us.


It still looks like a golf divot.
"Dantu's divot. An antipodal shock feature."
Ever seen an elliptical water-drop-basin? You let a drop of water fall at one focus, the ripples spread and reflect,
the reflections converge, and a drop of water jumps up from the other focus.

Mimas has a huge crater, and at the other side the crust is broken up by a series of cracks and chasms.
If you think back to Vesta, there is some interesting topography antipodal to the Rheasilvia impact basin and a few peer reviewed papers. Image of Vesta below.
Basically, at Vesta, the antipodal area is uplifted with a (probably) later crater at the focus and a "splat" area where craters are missing or disrupted.

At Ceres, Lonely Mountain is just about antipodal to Dantu crater. The antipodal area has valleys/faults, a crater, and the Lonely Mountain.
Situation is bizarre; looks as if a chunk of crust poped out, settled back to the surface, followed by weathering to create smooth talus slopes.
Attached thumbnail(s)
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hendric
post Aug 27 2015, 03:56 PM
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Ice I surprised me at being stable to near gigapascal pressures when I checked, so I suppose it is possible that as a Cerean mantle/ocean freezed out, the pressure underground caused/causes water volcanism, or ice extrusion, or crustal tilting of large blocks like this. That's what I was just thinking, that it looks like a portion of crust has been pushed out along a couple of fracture lines.

I can buy a lack of cryovolcanic features on Ceres based on not having enough energy when the crust was thin, and now that the crust has thickened any water freezes before reaching the surface, pushing up on this block, similar to the dome at Mount St. Helens. (neat time lapse at https://www.youtube.com/watch?v=h6B1myUKAS4 ) The wrinkle is the singular rarity of this mountain - was this the weakest spot on the crust, and the pressure from beneath isn't high enough to push any where else?

With the layers visible in the slopes, I wonder if those are not typical angle-of-repose talus slopes, but slopes caused by sublimation off the original cliffs as they extruded, similar to the Grand Canyon with sunlight instead of water acting as the erosive force? With the original crust acting as a protective "cap" on the top. Except I would expect the south side (closest to the crater) to be less eroded. (scratch scratch)

Someone care to guess the volume of the Lonely Mountain? (I keep hearing dwarven singing!)


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Space Enthusiast Richard Hendricks
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"The engineers, as usual, made a tremendous fuss. Again as usual, they did the job in half the time they had dismissed as being absolutely impossible." --Rescue Party, Arthur C Clarke
Mother Nature is the final inspector of all quality.
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Habukaz
post Aug 27 2015, 04:06 PM
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Ooo, look at that:

Attached Image

Something happened here. tongue.gif (and not very long ago)

http://photojournal.jpl.nasa.gov/catalog/PIA19635


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Habukaz
post Aug 27 2015, 04:54 PM
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After searching a bit, it seems almost certainly to be an area featured in Survey images 13, 24 and 25.

Seems like a regular landslide related to a crater sitting on the rim of a much larger crater:

Attached Image


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HSchirmer
post Aug 27 2015, 05:06 PM
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QUOTE (hendric @ Aug 27 2015, 03:56 PM) *
Ice I surprised me at being stable to near gigapascal pressures when I checked,
(snip)
That's what I was just thinking, that it looks like a portion of crust has been pushed out along a couple of fracture lines.


Yep, found the correct term = "hertzian cone". When a piece of glass is shot by a bb-gun, you get a conical hole and a conical chip.
The shiny sides make the mountain look like a conical chip that was knocked off, flipped over, and landed beside the hole.


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Herobrine
post Aug 27 2015, 05:18 PM
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QUOTE (Habukaz @ Aug 27 2015, 05:27 AM) *
By the way, I just realised that Gaue crater is similar in size (84 km) to Occator (90 km), so to get an idea of what Occator will look like to us shortly, take a look at the image of Gaue.

I'm looking forward to our first look at Occator from HAMO. In July, I put together this preview of what we can expect in terms of Occator size at HAMO and LAMO in Framing Camera imagery.
Attached Image

Note: That image is 1/4 actual resolution (each frame is shown at 256x256 instead of 1024x1024)
LAMO is going to be mind-blowing; the area of the spots will fill the entire frame.

In case it isn't obvious, the top row contains images from the second mapping orbit; the middle row contains simulated views from HAMO; the bottom row contains simulated views from LAMO.

Edit: Updated the image, adding the most recently published survey orbit image of Occator (as long as I'm reposting, I might as well update/improve it).
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Bill Harris
post Aug 27 2015, 05:38 PM
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QUOTE (habukaz)
Something happened here. (and not very long ago)


Yes. This relates to a very common Cerean feature, what I informally call a "flowage" or "slippage", for lack of an equivalent terrestrial analog. This has been seen in the SO images where a large (on the order of hundreds of Km) of the surface slip and flow in a fluidic manner. This occurs "internal" to craters as well as "external" to craters, and seems different than simple mass-wasting (although there are similarities).

This particular feature in HA-4 is on the order of 15-20 Km is size, which by terrestrial standards would be a continental catastrophe.

Tighten your seatbelts. This is only the fourth HAMO image... ohmy.gif

--Bill


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Daniele_bianchin...
post Aug 27 2015, 09:22 PM
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Probably my eyes but resemble a cone ;-)


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