IPB

Welcome Guest ( Log In | Register )

31 Pages V  « < 13 14 15 16 17 > »   
Reply to this topicStart new topic
Dawn's first orbit, including RC3, March 6, 2015- June 15, 2015
Phil Stooke
post May 13 2015, 02:09 PM
Post #211


Solar System Cartographer
****

Group: Members
Posts: 10121
Joined: 5-April 05
From: Canada
Member No.: 227



There are similar valleys on Iapetus associated with the large basin Falsaron, NW of Turgis. All of these are secondary crater chains. See also Vallis Bouvard and Vallis Inghirami on the Moon. None of these are tectonic rifts. It is really not a good idea to use the term rift with its tectonic implications.

Phil



--------------------
... because the Solar System ain't gonna map itself.

Also to be found posting similar content on https://mastodon.social/@PhilStooke
NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain)
Go to the top of the page
 
+Quote Post
Gladstoner
post May 13 2015, 03:16 PM
Post #212


Member
***

Group: Members
Posts: 714
Joined: 3-January 08
Member No.: 3995



The rifts around bright-spot crater are more or less parallel with rifts to the south (red):

Attached Image


These were visible in earlier images:

Attached Image


They seem to be associated with the resurfaced area shaded in yellow. I thought these features all resulted from the large impact (just beyond the terminator), but now I'm not so sure.
Go to the top of the page
 
+Quote Post
ZLD
post May 13 2015, 04:29 PM
Post #213


Member
***

Group: Members
Posts: 555
Joined: 27-September 10
Member No.: 5458



The green lines to the left and upper left of the 'Spot 5' area are definitely related to crater chains.
Attached Image


The lower right area could be rifts. I think it could be possible that the spidering lines near 'Spot 5' could be related in some way to whatever has gone on in that area.
Attached Image


Maybe the liquid ocean has most recently only existed under this section of the crust and each time a very large object impacts, it oscillates the water below cavitates, similar to if you strike the top of a beer bottle and it causes the bottom to blow out.

edit: terminology


--------------------
Go to the top of the page
 
+Quote Post
dvandorn
post May 13 2015, 07:13 PM
Post #214


Senior Member
****

Group: Members
Posts: 3419
Joined: 9-February 04
From: Minneapolis, MN, USA
Member No.: 15



Remember that tectonic cracking of a crust can express itself as chains of endogenous collapse pits. There is at least one major rift in the pictures above that expresses itself as semi-arcuate with straight, steep sides at one end and devolving into chains of craters as it becomes narrower and less distinct at the other end.

Let's wait for closer imagery before we jump to conclusions, eh?


--------------------
“The trouble ain't that there is too many fools, but that the lightning ain't distributed right.” -Mark Twain
Go to the top of the page
 
+Quote Post
Bill Harris
post May 13 2015, 07:35 PM
Post #215


Senior Member
****

Group: Members
Posts: 2997
Joined: 30-October 04
Member No.: 105



Please, continue to discuss and speculate...


--------------------
Go to the top of the page
 
+Quote Post
Ken2
post May 13 2015, 07:54 PM
Post #216


Junior Member
**

Group: Members
Posts: 48
Joined: 20-December 14
Member No.: 7370



QUOTE (ZLD @ May 13 2015, 09:29 AM) *
Maybe the liquid ocean has most recently only existed under this section of the crust and each time a very large object impacts, it oscillates the water below cavitates, similar to if you strike the top of a beer bottle and it causes the bottom to blow out[/url].


I am a big proponent of impacts transferring energy to the opposite side of a body and causing eruptions. I don't have any iron clad examples - this article has a nice visualizations but is earth specific though mentions applicability to other bodies and a crater on Mercury. http://www.princeton.edu/main/news/archive/S31/90/32S94/

Anyways I wonder if it's more than a coincidence that one of the largest more recent appearing craters is opposite the mountain, and close to some of it's adjacent rifts. Maybe Ceres was mostly liquid when it hit and caused an antipode eruption?

Attached Image

Attached Image

Attached Image


Go to the top of the page
 
+Quote Post
Gladstoner
post May 13 2015, 08:04 PM
Post #217


Member
***

Group: Members
Posts: 714
Joined: 3-January 08
Member No.: 3995



Piazzi (contrast enhanced):

Attached Image


There is an intriguing mix of light spots and dark mottling around the southern side of the large crater. Since this area may coincide with elevated water vapor levels, it will be especially interesting when the high-res images come in.

Oddly enough, there hasn't been any mention of this feature lately.
Go to the top of the page
 
+Quote Post
TheAnt
post May 14 2015, 11:38 AM
Post #218


Member
***

Group: Members
Posts: 495
Joined: 12-February 12
Member No.: 6336



QUOTE (Zelenyikot @ May 11 2015, 11:36 PM) *
It look like volcano


Thank you Zelenyikot, your image animation do indeed suggest it is conical shaped. If it turn out to be the case, we're in for a few raised eyebrows and we will have to lobby to have it named Saint-Exupéry. =)
Go to the top of the page
 
+Quote Post
Ken2
post May 14 2015, 04:50 PM
Post #219


Junior Member
**

Group: Members
Posts: 48
Joined: 20-December 14
Member No.: 7370



QUOTE (nprev @ May 8 2015, 11:44 AM) *
Those look a lot more like data dropouts or something else far more mundane than mini-moons or caves. Let's please not jump right to the most exciting (and improbable) conclusions here. wink.gif


QUOTE (dvandorn @ May 13 2015, 11:13 AM) *
Let's wait for closer imagery before we jump to conclusions, eh?


Sorry to be Off Topic here for a second [moderators feel free to move this potentially contentious post elsewhere] - but I think it's important to future discussion in an unmatched year of recent unmanned exploration: comet CG, Ceres and Pluto! :

I’m a newbie so don’t have the years of past precedence on these forums, so defer to the senior members, but I signed on because this appeared to be a unique place to discuss informed hypotheses and share in the exploration thrill that we all know that unmanned missions allow for.

If we wait for the official scientists to produce their peer reviewed papers months or years in the future - what’s left? just commenting “ah ha that’s what it was…” I fail to see the fun in that, and the fun aspect I suspect is what draws many to these forums. If we aren’t allowed to reasonably speculate - I would argue a science news feed would have similar value, and diminish the unique quality these forums allow for - which is exploration camaraderie (at least as much camaraderie as the internet allows for).

If I am off base here - senior members please set me (and all us newbies) straight.

Truly sorry to digress from the exciting topic at hand - but it's an important point I think for what gets commented - especially during the next 6 months of heavy first time exploration.
Go to the top of the page
 
+Quote Post
elakdawalla
post May 14 2015, 05:48 PM
Post #220


Administrator
****

Group: Admin
Posts: 5172
Joined: 4-August 05
From: Pasadena, CA, USA, Earth
Member No.: 454



There is a difference between observations; inferences supported by evidence; and proposing things that are physically impossible, dramatically contradictory to the conclusions already made by scientists, much less likely than more reasonable explanations, and unprecedented elsewhere in the solar system. The thing that makes this forum great is the fact that we permit only well-grounded speculation; it means active scientists and engineers can enjoy discussion here.


--------------------
My website - My Patreon - @elakdawalla on Twitter - Please support unmannedspaceflight.com by donating here.
Go to the top of the page
 
+Quote Post
ngunn
post May 14 2015, 05:51 PM
Post #221


Senior Member
****

Group: Members
Posts: 3516
Joined: 4-November 05
From: North Wales
Member No.: 542



dvandorn wasn't warning anyone, just expressing an opinion.
Note what Bill Harris said in the post following dvandorn's:
Please, continue to discuss and speculate...



Go to the top of the page
 
+Quote Post
Gladstoner
post May 14 2015, 09:23 PM
Post #222


Member
***

Group: Members
Posts: 714
Joined: 3-January 08
Member No.: 3995



And then there is this subtly shaded area to the north and east of the bright spots (contrast enhanced):


Attached Image


Most interesting to me is the sharp boundary between albedos that seems to extend north (and southeast?) from the primary bright spot. This appears to be independent of topography. I have a process or two in mind, but will wait for higher-res images....

Is this the same as the dark halo surrounding the bright spot ('Region A') visible in pre-Dawn observations?

----------

One more thing to mention....

So we have two areas ('Piazzi' and 'Region A') that turn out to be clusters of bright spots (of varying size and extent) surrounded by subtly shaded areas. These regions also happen to coincide with areas with elevated water vapor levels:

Attached Image


Again, mere coincidence has to be assumed until more data comes in.
Go to the top of the page
 
+Quote Post
RotoSequence
post May 14 2015, 09:56 PM
Post #223


Newbie
*

Group: Members
Posts: 8
Joined: 20-April 15
Member No.: 7446



QUOTE (Gladstoner @ May 14 2015, 02:23 PM) *
And then there is this subtly shaded area to the north and east of the bright spots (contrast enhanced):


Attached Image


Most interesting to me is the sharp boundary between albedos that seems to extend north (and southeast?) from the primary bright spot. This appears to be independent of topography. I have a process or two in mind, but will wait for higher-res images....

Is this the same as the dark halo surrounding the bright spot ('Region A') visible in pre-Dawn observations?


Maybe feature 5 is the remains of a shallow angle, low velocity impact...? Great catch, Gladstoner!
Go to the top of the page
 
+Quote Post
alk3997
post May 14 2015, 10:42 PM
Post #224


Member
***

Group: Members
Posts: 112
Joined: 31-January 15
From: Houston, TX USA
Member No.: 7390



QUOTE (RotoSequence @ May 14 2015, 04:56 PM) *
Maybe feature 5 is the remains of a shallow angle, low velocity impact...? Great catch, Gladstoner!


...the remnants of the original covering of the bright spots are the ejecta blanket to the north and northwest. The bright spots are the underlying layer of Ceres (composed of?).

In this (unproven) scenario the impactor was split just before impact.

It would require lower mass, lower velocity impactor at a much steeper angle than I had originally theorized but it seems to fit the available evidence so far. I suppose the bright spots could be the impactor and it would still fit the data.

That it's inside a crater is just coincidence, or expected given the large number of craters.

Andy
Go to the top of the page
 
+Quote Post
dvandorn
post May 15 2015, 12:47 AM
Post #225


Senior Member
****

Group: Members
Posts: 3419
Joined: 9-February 04
From: Minneapolis, MN, USA
Member No.: 15



QUOTE (ngunn @ May 14 2015, 11:51 AM) *
dvandorn wasn't warning anyone, just expressing an opinion.
Note what Bill Harris said in the post following dvandorn's:
Please, continue to discuss and speculate...


Oh, yes -- I love to speculate. I sure didn't mean to quash speculation! I was encouraging it, I thought, by bringing up reasons other than just long-string impacts for the formation of crater chains.

I guess we've been pushing the "let's wait for better pictures" line on Dawn's approach to Ceres so much, it's a little hard to stop. We are now seeing sufficient detail to start some serious speculating. So, I take it back -- let's not wait for better pictures, let's see what we can see in the current ones. smile.gif

In that spirit, I want to share a general impression from the pictures to date, though it's something I've noted before. And it fits in with a lot of the other observations.

It looks to me like Ceres has been through several epochs of what I'm beginning to dub, in my head, as "splash resurfacing." I keep thinking I'm seeing a lot of overlapping units, all of which are cratered to some extent, but all of which also appear to cover over much older cratered terrains. The smoothest areas seem to be where two splash-emplaced units overlap, where one was relatively young when the second was emplaced. There seem to be quite observable units, classifiable by superposition.

I'm getting a sense of a body that, upon impact, splashes rather than creating the type of ejecta we're used to seeing on Earth, the Moon, Mars, etc. We're talking impacts large enough to form what would be basins on larger, rockier worlds. On Ceres, such events seem to have rebounded and relaxed, perhaps to the point of being impossible to recognize after a gigayear or two, so you don't see "basins," but that's the kind of impact I'm thinking about.

Those impacts look to have created sheets of material that fly around Ceres for a while and then emplace themselves, perhaps in patterns and locations far enough removed from the impact to make it difficult to work resurfacing events back to their impacts.

Some of the squirrely arcuate ridges and gorges may be the result of multiple splash sheets created by a given impact interacting with each other before they fell back down onto the surface. After all, Ceres is a small body, so ejecta can fly around that little world a few times before finally re-impacting the surface.

I'm wondering what exactly happens when impact heating from a Cerean "basin-forming event" is very rapidly infused into gigatons of relatively warm ice...


--------------------
“The trouble ain't that there is too many fools, but that the lightning ain't distributed right.” -Mark Twain
Go to the top of the page
 
+Quote Post

31 Pages V  « < 13 14 15 16 17 > » 
Reply to this topicStart new topic

 



RSS Lo-Fi Version Time is now: 19th March 2024 - 02:39 AM
RULES AND GUIDELINES
Please read the Forum Rules and Guidelines before posting.

IMAGE COPYRIGHT
Images posted on UnmannedSpaceflight.com may be copyrighted. Do not reproduce without permission. Read here for further information on space images and copyright.

OPINIONS AND MODERATION
Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators.
SUPPORT THE FORUM
Unmannedspaceflight.com is funded by the Planetary Society. Please consider supporting our work and many other projects by donating to the Society or becoming a member.