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Unmanned Spaceflight.com _ Dawn _ Dawn's first orbit, including RC3

Posted by: Ron Hobbs Mar 6 2015, 03:23 PM

Dawn is now officially in orbit around (1) Ceres!

Congratulations, NASA. Nice images of crescent Ceres.

http://www.nasa.gov/press/2015/march/nasa-spacecraft-becomes-first-to-orbit-a-dwarf-planet/index.html#.VPnF6XzF-YQ

Posted by: elakdawalla Mar 6 2015, 04:29 PM

I thought it was time for a new thread, now that Dawn's in its first orbit. We can look forward to a couple more op navs, on April 10 and 14, and then RC3 later in the month. http://www.unmannedspaceflight.com/index.php?showtopic=7960; let's use this thread for Op Navs 6 and 7 and RC3 and then we'll split again once Dawn reaches its first survey orbit.

Posted by: DrShank Mar 7 2015, 12:01 AM

QUOTE (elakdawalla @ Mar 6 2015, 10:29 AM) *
I thought it was time for a new thread, now that Dawn's in its first orbit. We can look forward to a couple more op navs, on April 10 and 14, and then RC3 later in the month. http://www.unmannedspaceflight.com/index.php?showtopic=7960; let's use this thread for Op Navs 6 and 7 and RC3 and then we'll split again once Dawn reaches its first survey orbit.



thanks emily!

i noticed in a prior thread that it said mapping starts in July. thats a bit of a misnomer as mapping starts in Survey Orbit in May (and one can count RC3 as a global map, at about 1.5 km resolution, which is comparable to much of Voyager at Saturn.) wows!

Posted by: Habukaz Mar 7 2015, 09:28 AM

What should nonetheless be correct is that a new mapping phase starts in July, namely HAMO; and that this is still the month New Horizon zooms past Pluto. wink.gif

Posted by: Sherbert Mar 8 2015, 12:36 AM

QUOTE (Habukaz @ Mar 7 2015, 09:28 AM) *
What should nonetheless be correct is that a new mapping phase starts in July, namely HAMO; and that this is still the month New Horizon zooms past Pluto. wink.gif

Also the time when the fireworks on 67P are expected to really start.

Posted by: ChrisC Mar 8 2015, 04:29 AM

From http://www.nasa.gov/press/2015/march/nasa-media-teleconference-today-on-first-spacecraft-to-successfully-enter-orbit/ :

QUOTE
NASA will host a media teleconference at 2 p.m. EST today [Friday] to discuss the historic arrival of the agency’s Dawn spacecraft at the dwarf planet Ceres. ... Participants in the teleconference will be:
- Jim Green, director, Planetary Science Division, NASA Headquarters, Washington
- Carol Raymond, Dawn mission deputy principal investigator, Jet Propulsion Laboratory, Pasadena, California
The teleconference will be streamed live on NASA’s website, at: http://www.nasa.gov/newsaudio


Does anyone know if a recording of this telecon exists? Normally, at the end of a NASA telecon they offer a number that you can call into to hear it again -- inexplicably, they only offer that number DURING the call itself. Also, JPL will sometimes take the audio and make a video out of it (synced with slides if there are any) and upload to the Ustream or Youtube account.

Or was there absolutely nothing of interest said during the telecon, just the usual recapping of what's happened?

Thanks!

Posted by: Gerald Mar 8 2015, 02:27 PM

http://www.ustream.tv/recorded/59452133.

Posted by: ChrisC Mar 8 2015, 08:49 PM

QUOTE (Gerald @ Mar 8 2015, 09:27 AM) *
http://www.ustream.tv/recorded/59452133.


Thanks but that's the PREVIEW briefing, that aired on NASA TV on Monday. I'm talking about the teleconference (media phone call) from Friday.

Posted by: anticitizen2 Mar 9 2015, 03:58 PM

Searched for it on YouTube:

https://www.youtube.com/watch?v=Qk0Cr0Z13hc

Edit: finally had a chance to listen to it - nothing new was said, really.

Posted by: TheAnt Mar 9 2015, 11:03 PM

QUOTE (Sherbert @ Mar 8 2015, 01:36 AM) *
Also the time when the fireworks on 67P are expected to really start.


And Voyager 2 might break out into interstellar space at about the same time also. The values for the interstellar >70 MeV protons have been slowly climbing to the same value as for V2 - though if the current trend holds it might happen a few months later.

Posted by: ChrisC Mar 10 2015, 02:32 AM

QUOTE (anticitizen2 @ Mar 9 2015, 10:58 AM) *
Searched for it on YouTube:
https://www.youtube.com/watch?v=Qk0Cr0Z13hc
Edit: finally had a chance to listen to it - nothing new was said, really.


THANK YOU!!!

Posted by: peter59 Mar 11 2015, 01:53 PM

It must be an unusual sight. The narrow sickle of Ceres with constellation of Orion in background.


Posted by: Mr Valiant Mar 11 2015, 03:48 PM

QUOTE (peter59 @ Mar 11 2015, 01:53 PM) *
It must be an unusual sight. The narrow sickle of Ceres with constellation of Orion in background.



Thanks Peter,
just dipped outside for a look and there is Orion, laying in the west. Go Dawn.

Posted by: Gladstoner Mar 12 2015, 02:44 AM

QUOTE (peter59 @ Mar 11 2015, 07:53 AM) *
It must be an unusual sight. The narrow sickle of Ceres with constellation of Orion in background.


Thanks. That certainly puts things into perspective.

Posted by: marsbug Mar 12 2015, 08:02 AM

QUOTE (peter59 @ Mar 11 2015, 01:53 PM) *
It must be an unusual sight. The narrow sickle of Ceres with constellation of Orion in background.


Oh my, talk about making the familiar unusual....

Posted by: Malmer Mar 12 2015, 10:08 AM

I like these perspective jolting moments. My absolute favorite is earth and the moon seen from mercury during the lunar eclipse.

Posted by: Habukaz Apr 15 2015, 11:12 AM

Dawn is currently communicating with Earth. Here's hoping for some of spot(s) 5. smile.gif

http://eyes.nasa.gov/dsn/dsn.html

Posted by: JohnVV Apr 16 2015, 04:53 AM

for those interested this is the orbit for the Dawn spacecraft as in spirals down to a lower orbit over the next few weeks

http://imgbox.com/Zbsakx7n

the red line is the spacecraft orbit
generated from the
dawn_ql_150219-150531_150415_v1.bsp
dawn_ref_150423-150704_150414_DA400_v1.bsp

naif kernels

Posted by: belleraphon1 Apr 16 2015, 07:09 PM

Dawn Glimpses Ceres' North Pole
http://dawn.jpl.nasa.gov/news/Dawn_glimpses_Ceres_north_pole.asp

Posted by: elakdawalla Apr 16 2015, 07:11 PM

http://photojournal.jpl.nasa.gov/catalog/PIA19317 Very cool smile.gif

http://planetary.s3.amazonaws.com/assets/images/9-small-bodies/2015/20150416_PIA19317_cropped.gif

On Twitter, Brian Wolven asked me if the prominent bright peaks seen at the right-hand limb at the beginning of the animation were the two bright spots. I tried to figure out the answer to that, but couldn't. I made the attached polar projection of the northern hemisphere of the DEM from JohnVV's map, but I couldn't match crater features.

 

Posted by: JohnVV Apr 16 2015, 07:31 PM

it would NOT be visible YET in the April 10 images

it is at 20 deg North
what is visible in that gif is 50+ to 90 north
as you can see in these two screenshots ( if the naif kernels are accurate, i have been having MAJOR issues with some of them )
added extra light to the scene
-- FOR APRIL 10 like the gif--
near the center
http://imgbox.com/dM3lq98E
- off to the right side of ceres
http://imgbox.com/w16sXZ3O

Posted by: Habukaz Apr 16 2015, 07:36 PM

Pleasantly surprised to see that OpNav 6 was released today. Something odd happens when I try to extract the individual frames with IrfanView, though: the frames come out in all sorts of sizes. blink.gif (edit: never mind, Python to the rescue)

In the http://dawnblog.jpl.nasa.gov/?p=2437 Dawn Journal, it was mentioned that spot(s) 5 would not be visible in OpNav 6:

QUOTE
As we describe below, Dawn’s extensive photographic coverage of the sunlit terrain in early May will include these bright spots. They will not be in view, however, when Dawn spies the thin crescent of Ceres in its next optical navigation session, scheduled for April 10


so I think it would be odd if they suddenly turned up anyway.

Posted by: elakdawalla Apr 16 2015, 07:37 PM

QUOTE (JohnVV @ Apr 16 2015, 12:31 PM) *
it would NOT be visible YET

Thanks for those simulations, they are really helpful.

Posted by: JohnVV Apr 16 2015, 08:12 PM

in the northpole image you posted the two side by side bright spots are the line here circled
http://imgbox.com/eyKemk3O

and it will be visible TODAY but not much better than before. just from a different angle
http://imgbox.com/zOtYgH7V

Posted by: Gladstoner Apr 16 2015, 09:18 PM

I think this mound (or mounds) in the large crater is a good candidate for the limb peaks:



Note the trio of craters circled in red:




They seem to correspond with the craters in red here:



Now extend a longitudinal line over the north pole here:



And here (north pole marked with 'N'):



The peaks are to the east of the line. The crater with the mound(s) is marked with a yellow box on the longitudinal map.

Posted by: Gerald Apr 17 2015, 04:14 AM

With the following assumed globes for PIA19317.gif OpNav6
http://imgur.com/Uly3i7f
I've obtained these projections:
http://imgur.com/6iCNY19
Addition of the projections to http://www.mpg.de/9003969/zoom.jpg:
http://imgur.com/s51ZHPM

The bright spot is probably just outside frame 20 of the sequence.

Posted by: JohnVV Apr 17 2015, 05:56 AM

aligning the animated gif with the textured mesh and lat long marks

the other "bright spot" is at 42 N and 0 long.
it is barely visible in the gif
3 frames from the gif with and without a spherical grid
the 0/360 long is top right on the sphere and you can see the major bright spot
http://imgbox.com/zCXHIJzX http://imgbox.com/JD6ir2dj
hidden under the horizon
http://imgbox.com/AYeFx6eJ http://imgbox.com/oJH036ds
almost visible on the top left
http://imgbox.com/P5SAWDVK http://imgbox.com/zCWItjeS

Posted by: Toma B Apr 17 2015, 08:20 AM

Ceres rotating back and forth in latest images from Dawn spacecraft.
I find it much easier to spot different surface details this way.


Posted by: TheAnt Apr 17 2015, 10:44 AM

QUOTE (Toma B @ Apr 17 2015, 10:20 AM) *
I find it much easier to spot different surface details this way.


Thank you for your effort Toma. Now this make me think the surface resemble a golf ball. =)

Posted by: mcgyver Apr 17 2015, 05:26 PM

QUOTE (Toma B @ Apr 17 2015, 08:20 AM) *
Ceres rotating back and forth in latest images from Dawn spacecraft.
I find it much easier to spot different surface details this way.


I can't figure out if bright spot is visible in the animation.
I place here the other available images for more comfortable comparisons:
http://cdn.phys.org/newman/csz/news/800/2015/1-dwarfplanetc.jpg
http://cdn.phys.org/newman/csz/news/800/2015/thisimageist.jpg
https://lightsinthedark.files.wordpress.com/2015/03/pia189231.jpg
http://www.jpl.nasa.gov/spaceimages/images/largesize/PIA19056_hires.jpg


I don't understand if I must link them or upload them or insert them in tag so I just add the links.

Posted by: djellison Apr 17 2015, 06:01 PM

QUOTE (mcgyver @ Apr 17 2015, 10:26 AM) *
I can't figure out if bright spot is visible in the animation.


It isn't.

Posted by: ZLD Apr 17 2015, 09:56 PM

Im rather curious about these two spots that appear in frame 6 and frame 7. Not necessarily from spot 5 but in the same vicinity. They are somewhat dim and on the left lim.


Posted by: JohnVV Apr 17 2015, 10:04 PM

ZLD - your map is upside down

That is the two side by side spots that are at 20 degrees NORTH and 240 degrees longitude and is visible in the added light 3d graphic I posted http://www.unmannedspaceflight.com/index.php?showtopic=7981&view=findpost&p=219593 of the two recreations that show where it WOULD be IF it was lite

http://www.unmannedspaceflight.com/index.php?s=&showtopic=7981&view=findpost&p=219593

http://imgbox.com/zCXHIJzX http://imgbox.com/JD6ir2dj
you can see in the first image ( added extra AMBIENT light ) to the 3d rendering

Posted by: Gladstoner Apr 17 2015, 10:39 PM

JohnVV, thanks much for the simulations with the grids. They really help to put things into perspective.

Also, have you yet added the grid to the global cylindrical map?

Posted by: JohnVV Apr 17 2015, 10:51 PM

the grid is dynamically added in the 3d program i am using .

Ceres's orbit is calculated using the JPL orbit data and Dawn's orbit is also calculated using it's orbital data the same data that the research scientists are using the naif kernels.

As to the map. The map posted is 0 long to 360 long ( 180 in the center ) a grid could be added ? but not really needed this very EARLY map is very low resolution 1024x512 pixels and the poles ARE MISSING.

In comparison the published Vesta map is 48 ppd ( 17,280 X 8,641 ) pixels .

Posted by: Habukaz Apr 20 2015, 01:59 PM

Is the dimmest bright spot resolved in the http://dawn.jpl.nasa.gov/news/Ceres_bright_spots_come_back_into_view.asp? It looks distinctly elongated in all frames where it "glows":




Posted by: djellison Apr 20 2015, 02:18 PM

QUOTE (Habukaz @ Apr 20 2015, 06:59 AM) *
Is the dimmest bright spot resolved...


The accompanying press release text clearly states

"The images show the brightest spot and its companion clearly standing out against their darker surroundings......"

Posted by: Habukaz Apr 20 2015, 03:15 PM

I don't see how that implies that they are resolved.

Posted by: centsworth_II Apr 20 2015, 03:17 PM

QUOTE (Habukaz @ Apr 20 2015, 09:59 AM) *
Is the dimmest bright spot resolved....
Are you asking if the impression that the elongated spot is split up into three parts can be trusted? Looks like it to me, but you know what my opinion's worth! laugh.gif

Posted by: Habukaz Apr 20 2015, 03:24 PM

Just noting that it looks like it spans more than one pixel at this resolution (and also that it looks elongated from this vantage point). Looking a bit more closely at the images, it seems almost certain to me that it is resolved; but I haven't seen any relevant comments from the science team.

Posted by: JohnVV Apr 20 2015, 04:40 PM

from the tiny gif that is PIA19064

it is looking like the one bright spot at 0 long.( 360 long.) and 42 North

is in fact ejecta from a crater ( i am GUESSING that the OTHER side by side bright spot at 240long and 20 North are ALSO ejecta)

4x enlargements from the 8 bit INDEXED gif


Posted by: StarryKnight Apr 20 2015, 04:50 PM

The surface between the craters looks very smooth. The smooth areas between craters may only appear that way because of smaller craters can't be seen due to the low resolution of the current set of images. But, so far, there does not appear to be mountains or ridges between the craters.

Also, when I imagine a generic crater, say on the moon, I think of the surrounding of it sloping up fairly steeply then the surface dropping sharply as you go into the crater. But I don't see much of a rise on the outside edges of the craters. Are these craters really that smooth or does it look like that because the resolution or sun angle in these images? If they are really that slightly sloped on the outside, could it be because of what might be below the surface or


Posted by: JohnVV Apr 20 2015, 05:15 PM

do to the fact that Ceres is very high in ices the craters have flat bottoms and are shallow

the one in the crops i posted looks to be on one of the ridges and came in at a very shallow angle

some of the "smoothness "is do to the 4x enlargement and that the original crop was only 128 px on a side ( rather small)

keep in mind that the spacecraft is NOT YET even in a near circular orbit YET
and this set of images is from April 14/15
-- LAST WEEK

Posted by: TheAnt Apr 20 2015, 06:02 PM

QUOTE (Habukaz @ Apr 20 2015, 05:24 PM) *
Looking a bit more closely at the images, it seems almost certain to me that it is resolved; but I haven't seen any relevant comments from the science team.


Yes I tend to agree thinking its resolved or nearly so on the first image of the sequence, but on the subsequent images it seem to get saturated and float into adjacent pixel areas -and so larger than it actually is -again


Edit: It's not the first, but frames 8 and 9, the page loaded to slow so I missed the early part of the rotation sequence, but I did separate the images after the post to find out.

Posted by: Toma B Apr 20 2015, 06:06 PM

https://www.flickr.com/photos/tomabandin/17212771212/sizes/o/

https://www.dropbox.com/s/x6shumsbor73zuo/Frames%20of%20animation%20Ceres%20Apr15th.zip?dl=0

Posted by: scalbers Apr 20 2015, 06:10 PM

QUOTE (TheAnt @ Apr 20 2015, 06:02 PM) *
Yes I tend to agree thinking its resolved or nearly so on the first image of the sequence, but on the subsequent images it seem to get saturated and float into adjacent pixel areas -and so larger than it actually is -again

The linear arrangement almost has the look of the "Voyager Mountains" on Iapetus...

Posted by: ZLD Apr 20 2015, 09:27 PM

Performed some slight enhancements on frame 10 of the PIA19064 animation. Cropped, luminance adjustment, deconvolution and scaled 200%.



And again with frame 11.


These are stretched until the bright region is slightly below max saturation.

Posted by: Gladstoner Apr 20 2015, 10:55 PM

The bright spot seems to be less prominent when on the morning terminator than on the evening. One possibility is that much of the bright material is on a west-facing slope.

Posted by: dudley Apr 21 2015, 02:00 AM

Dr. Chris Russell, principal investigator of the Dawn mission, indicated in an e mail today to NBC News that even at the current resolution (1300 2100 meters/pixel) the bright spots were not resolved. This will presumably necessitate a marked revision upward of the albedo of the spots, which was set a minimum of 40 percent, based on the previous resolution of 3.7 kilometers/pixel.
http://www.nbcnews.com/science/space/dwarf-planet-ceres-white-spots-return-dawns-new-video-n344981

Posted by: Explorer1 Apr 21 2015, 03:48 AM

The fact that these things were visible from Earth still blows my mind. How small would they have to be before we get in the range of an Enceladean albedo?

Posted by: Gerald Apr 21 2015, 11:14 AM

Assuming the globes
http://imgur.com/xBlPdKy
here a forward/back animation (1200 pixels) of rectangular roughly map-projected versions of the 20-frames OpNav7 sequence http://photojournal.jpl.nasa.gov/archive/PIA19064.gif, aligned to http://www.mpg.de/9003969/zoom.jpg:
http://imgur.com/6lnlt2a
(NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/"Gerald")

http://imgur.com/a/nDD6P.

Posted by: dudley Apr 21 2015, 02:11 PM

QUOTE (Explorer1 @ Apr 21 2015, 04:48 AM) *
The fact that these things were visible from Earth still blows my mind. How small would they have to be before we get in the range of an Enceladean albedo?

Well, it appears that the ratio of an area 3.7 kilometers in diameter to one that is 1.3 km across is about 8.1 to 1. I'm assuming that albedo is inversely proportional to reflective area. If I'm not mistaken, one could multiply the old albedo figure of 0.4 by the 8.1 ratio to get the minimum new albedo.

Posted by: Gerald Apr 21 2015, 03:25 PM

Albedos greater than 1.0 are very rare in nature.

... Forth-back animation of polar projections of OpNav7 (same globes assumed as above) :
http://postimg.org/image/71p1s7i2r/

http://imgur.com/a/LLHC3#0.

Posted by: alk3997 Apr 21 2015, 03:32 PM

QUOTE (Gladstoner @ Apr 20 2015, 04:55 PM) *
The bright spot seems to be less prominent when on the morning terminator than on the evening. One possibility is that much of the bright material is on a west-facing slope.


If this were a geologically recent active region, wouldn't a reasonable expectation be that the crater floor is smooth as the material flows or falls onto the floor? It's hard to tell whether the crater floor in the zoomed-in version is itself cratered or those are image processing artifacts.

My money is still on a shallow angle impact causing the center bright spot with a secondary impact causing the second spot. It also explains the variability in brightness between different viewing angles.

Andy

Posted by: fredk Apr 21 2015, 03:37 PM

QUOTE (dudley @ Apr 21 2015, 03:00 AM) *
Dr. Chris Russell, principal investigator of the Dawn mission, indicated in an e mail today to NBC News that even at the current resolution (1300 meters/pixel) the bright spots were not resolved.
It probably depends on exactly what you mean by "resolved". There's certainly not much detail visible in both of the two spot 5 subspots, but I would call them "resolved" in the sense that they are clearly larger than the PSF. Both of the subspots are elongated, and the orienation of elongation rotates with Ceres. This means the elongation can't be due to bad optics (eg, astigmatism) and almost certainly not due to motion blur during the exposure. Similarly, it is extremely unlikely for pixel noise to conspire to produce elongation in both subspots rotating consistently with Ceres's rotation, even though we're looking at only a small number of pixels here (ie, S/N looks good judging from frame-to-frame consistency).

It appears that the fainter subspot (upper in my animation below) is composed of two "sub-subspots" (again, the consistency from frame to frame argues against pixel noise). The brightest subspot (lower in my animation) perhaps also consists of two sub-subspots, the lower of which appears first and the upper which brightens. As others have pointed out, these sorts of brightness variations could be simply due to variable geometry of exposed surfaces/shadowing.


Posted by: Gerald Apr 21 2015, 03:48 PM

I'd assign the apparent split of the fainter spot to a more or less concentrical topographical feature in the crater. So it's not necessarily an albedo feature, but possibly an "inclination" feature.

Posted by: fredk Apr 21 2015, 04:55 PM

But the upper double spot only brightens as you go from frame to frame. If the dark gap between the two sub-subspots was due to inclination, the dark gap should have been more prominent in the earlier frames when the illumination angle was lower.

Of course the real problem is that we're arguing over only a few pixels here. One way to improve things while we wait is to note that the spot 5 crater remains at roughly the same distance from the limb in all the frames, ie we're roughly "looking straight down at the north pole". So the viewing geometry for the crater is roughly constant. So someone could usefully do a poor-man's superresolution by enlarging (say 4x), rotating, and then stacking the images...

Posted by: dudley Apr 21 2015, 06:25 PM

QUOTE (fredk @ Apr 21 2015, 03:37 PM) *
It probably depends on exactly what you mean by "resolved". There's certainly not much detail visible in both of the two spot 5 subspots, but I would call them "resolved" in the sense that they are clearly larger than the PSF.

I recall when only one bright spot was discernible in this crater, then there were two. There was apparently no claim that the spot had been optically resolved at this point. When Dr. Russell says that the spots are not resolved because they're too small, I'm inclined to rely on that, given his expertise, and knowledge of this particular situation.
It does not appear to me that the brighter of the two spots is even separated into two distinct parts, which seems to argue against any reasonable definition of the word 'resolved'. The variable lighting of portions of this spot could have any one of several explanations. The bright spot sometimes appeared to be elongated in the images, long before there was any thought that it might be optically resolved.

ADMIN NOTE: Everyone - I think that we can drop the discussion over the word 'resolved'. You can go into the 'micron' scale and still not fully "resolve" an object. Let's just wait for better images that will help to identify the nature of these features. Not long now.

Posted by: JohnVV Apr 21 2015, 06:34 PM

QUOTE
The bright spot seems to be less prominent when on the morning terminator than on the evening. One possibility is that much of the bright material is on a west-facing slope.

as one can see in the second attached image in post # 41


it is on a west facing slope


as to the other one
WE WELL SEE --- once there are better images

Posted by: dvandorn Apr 21 2015, 07:00 PM

In the previous image, and also in the animations showing this region, I'm tempted to say that it's not ejecta that's so bright. This "spot" is resolved to the point that, when not saturating the ccd's, it looks like a pyramidal structure (in shape, not at all suggesting it was artificially constructed) that is definitely lighter in color than the surrounding terrain. It doesn't exactly follow the curves of the crater wall it seems to overly, either.

I'm wondering if this could be a constructional landform -- looks a little like a volcano-like structure in this image, at any rate.

Boy, it'll be nice to get better pictures of these areas. Patience... I must learn patience...

-the other Doug

Posted by: Webscientist Apr 21 2015, 07:52 PM

QUOTE (scalbers @ Apr 20 2015, 07:10 PM) *
The linear arrangement almost has the look of the "Voyager Mountains" on Iapetus...


Well found for the analogy Scalbers!

I've extracted a portion of the Voyager Moutains and the bright patch of Iapetus, about 5 km long, looks like the bright spot of Ceres... to a certain extent!


 

Posted by: Gladstoner Apr 21 2015, 08:07 PM

QUOTE (fredk @ Apr 21 2015, 09:37 AM) *
The brightest subspot (lower in my animation) perhaps also consists of two sub-subspots, the lower of which appears first and the upper which brightens. As others have pointed out, these sorts of brightness variations could be simply due to variable geometry of exposed surfaces/shadowing.



That animation really helps.

I'm seeing (imagining) something along these lines:



The main bright area seems to be in the western part of a little depression of some kind, with the brightest material not becoming visible until the shadow clears the slope.

(Nothing in the drawing is necessarily to scale; plus, I intentionally left out the other bright spot(s).)

Posted by: elakdawalla Apr 21 2015, 09:10 PM

Here's a slightly different take on this sequence of images. (Click to enlarge)

http://planetary.s3.amazonaws.com/assets/images/9-small-bodies/2015/20150421_PIA19064_cropped.gif

http://planetary.s3.amazonaws.com/assets/images/9-small-bodies/2015/20150421_ceres_brightspot_12views.png

Posted by: Ken2 Apr 21 2015, 09:20 PM

A heavily zoomed and exposure enhanced version of the first 3 frames of the bright spot. (this may have introduced artifacts - but overall it allows a better overall visualization IMHO)

I think the these frames clearly show the outline of a crater with the far wall getting the first bit of sunlight. As the sun rises in the crater the crater gets more and more illuminated causing pixel saturation and bleed for the subsequent not shown images, but roughly corresponding to the crater dimensions.

[click to animate the GIF]


Posted by: ZLD Apr 21 2015, 10:16 PM

Is there any speculation on what would be able to leave such a smooth, shiny depression? To me, it appears that much of the crater may be a similar make up because as the sun angle decreases, the crater continues to light up. Seems to be smack dab in the middle as well. Possibly a remnant of some cryo-gyser sort of blow out maybe?

Posted by: JohnVV Apr 21 2015, 10:24 PM

well as of the 19th
the Dawn spacecraft would have gotten a good view of the area



and today the 21st

Posted by: Gerald Apr 21 2015, 10:50 PM

QUOTE (fredk @ Apr 21 2015, 05:55 PM) *
...So someone could usefully do a poor-man's superresolution by enlarging (say 4x), rotating, and then stacking the images...

PIA19064, 4x magnified (probably bicubic), then polar-projected (bilinear interpolated) to 2880x2880 pixels, then cropped and registered, then pairwise averaged (stacked), sharpened, forth/back animated:


Posted by: Gladstoner Apr 21 2015, 11:05 PM

Is anyone else having issues with the released animated GIF not repeating/looping?

( http://dawn.jpl.nasa.gov/news/Ceres_bright_spots_come_back_into_view.asp )

Posted by: Gerald Apr 21 2015, 11:15 PM

Yes, with (outdated) Windows XP / Chrome, at least.

Posted by: PaulH51 Apr 22 2015, 01:43 AM

QUOTE (Gerald @ Apr 22 2015, 07:15 AM) *
Yes, with (outdated) Windows XP / Chrome, at least.

Also the same with W7 / Chrome

Posted by: JohnVV Apr 22 2015, 02:26 AM

it is a setting ON!!! the dawn web site !

THEY!!! have the gif set to "run once"

Posted by: nprev Apr 22 2015, 03:06 AM

Yeah, must be. I had to clear my cache to get it to run again. Hopefully this will be noticed and corrected soon; meanwhile, let's all be patient. wink.gif

Posted by: fredk Apr 22 2015, 03:48 AM

Works fine (even on ancient xp) if you download the gif and play in, eg, irfanview.

Posted by: elakdawalla Apr 22 2015, 04:14 AM

I edited it to loop forever (click to enlarge):

http://planetary.s3.amazonaws.com/assets/images/9-small-bodies/2015/20150421_PIA19064.gif

Posted by: Mr Valiant Apr 22 2015, 12:41 PM

Emily, great input. Like everyone here, hanging out for the hi resolution pics.
Anxiety level akin to Huygens.
We may actually be seeing a steady `volcanic eruption`.

Posted by: dudley Apr 26 2015, 11:27 PM

It's said that when Dawn's mission is finished, they'll park it permanently in orbit of Ceres. A good thing they won't have to feed coins to De meter.

Posted by: nprev Apr 27 2015, 01:17 AM

...aaaand, Dudley's banned. tongue.gif

Posted by: Mongo Apr 27 2015, 12:45 PM

QUOTE (nprev @ Apr 27 2015, 02:17 AM) *
...aaaand, Dudley's banned. tongue.gif


That was a joke, Ceres is the Roman equivalent of the Greek Demeter.

Unless you were also making a joke about making puns on this thread. I guess the smiley was a clue.

Posted by: tedstryk Apr 27 2015, 02:06 PM

QUOTE (Mongo @ Apr 27 2015, 01:45 PM) *
That was a joke, Ceres is the Roman equivalent of the Greek Demeter.

Unless you were also making a joke about making puns on this thread. I guess the smiley was a clue.


It is rather unforgivable laugh.gif

Posted by: dudley Apr 27 2015, 02:59 PM

It's just that I feel it's important to get some pun out of life!

Posted by: Holder of the Two Leashes Apr 29 2015, 02:28 PM

Looks like the Dawn website just underwent a major overhaul...

http://dawn.jpl.nasa.gov/

At first glance, I can't find where the "Where is Dawn now" simulated views have gone.

Posted by: StarryKnight Apr 29 2015, 03:43 PM

Yes. It looks like they've changed the user interface to be more tablet friendly, as many web sites are starting to do. Unfortunately, my primary web access (at work and at home) are desk tops, which aren't as user friendly as for these tablet friendly sites.

The "where is Dawn now" can be found by selecting the Menu button, then clicking (or tapping) on Mission. About a quarter of the way down the Mission page, you'll see "Where is Dawn now?" followed by a link labled "> View". Or you can just use this link here: http://dawn.jpl.nasa.gov/mission/live_shots.html

Posted by: JohnVV Apr 29 2015, 05:29 PM

all this "portrait" formatting on LANDSCAPE 16X9 screens !!!
( a TON of sites are doing this so...)

makes one REALLY WANT some of the by-gone days of what sites USED to look like

CODE
w3m http://dawn.jpl.nasa.gov/




nasa.gov 1996
http://web.archive.org/web/19961231235847/http://www.nasa.gov/

Posted by: Phil Stooke Apr 29 2015, 05:52 PM

I really don't like this new trend. It's a fad among web designers - like the one a year or two ago where everything on the screen would flash and shake as the cursor moved over it. The most basic principles of good design are being thrown out of the window, mainly because designers need to keep changing sites or they are out of a job.

If UMSF goes the same way I'm quitting! Or at least I would if there was anywhere else to go.

Phil

Posted by: MichaelJWP Apr 29 2015, 06:26 PM

A shame we're reduced to discussing website design, interesting though it is. I too prefer pages rather than the scroll-for-ever sites of today.

Anyone have any idea when we might see the next images, presumably there are some great shots since getting into orbit that we're not seeing yet?

Posted by: djellison Apr 29 2015, 06:35 PM

QUOTE (Phil Stooke @ Apr 29 2015, 09:52 AM) *
The most basic principles of good design are being thrown out of the window, mainly because designers need to keep changing sites or they are out of a job.


I can't stand this shift to 'trendy' websites either....but I have had visibility into the process behind the redesign for many of JPLs pages...and I can tell you, the demand for it isn't coming from designers, it's coming from management.

And when it's winning awards all over the place - it's not going to go away any time soon : http://www.jpl.nasa.gov/news/news.php?feature=4566

Posted by: JohnVV Apr 29 2015, 06:59 PM

with this getting off topic

i think most of us HAVE recently unbookmarked sites we used to use
Do to the now "handheld TELEPHONE !!!! " trend

but on a but of a different note
i DO find that the MOST useful sites ( content wise) look like this



a FTP page for the dawn spice kernels


Posted by: Habukaz Apr 29 2015, 07:31 PM

New RC3 image is out at the photojournal: http://photojournal.jpl.nasa.gov/catalog/PIA19319

Think it might show one of the interesting big craters near the south pole?

Posted by: Habukaz Apr 29 2015, 08:46 PM

Following up on that image, is the relatively crater-free area above the crater in this crop part of a massive landslide? Have we observed something similar on other bodies?



The crater floor also appears to be of a relatively young age.

Posted by: dvandorn Apr 29 2015, 08:56 PM

It looks more like a massive ejecta sheet to me, and we do see those commonly on our own Moon. They are most often seen, on the Moon, as ejecta from large basin impacts. As a comparison, take a look at the Fra Mauro formation on the Moon's near side.

In fact, this resembles that kind of structure quite a bit.

-the other Doug

Posted by: Gladstoner Apr 29 2015, 09:32 PM

Since we're on the subject of website design trends/fads, I'm not fond of the 'load more'- or 'fetch more images'-style of display. After awhile, the browser chokes and dies before all thumbnails, posts, etc. can be viewed. Two examples of this on well-known sites:

https://www.flickr.com/search/?q=ceres%20dawn

https://instagram.com/marscuriosity/

I guess I'm old fashioned, but I don't mind having to click 'page 2' to see the next 50 image thumbnails.

At least the image display formatting on the Dawn site is still 'old fashioned'.

---------

Ok. Back on topic:

That modified terrain around the large crater is intriguing. It does look like fresh ejecta, but from where?

Posted by: stevesliva Apr 29 2015, 09:39 PM

QUOTE (djellison @ Apr 29 2015, 01:35 PM) *
I can't stand this shift to 'trendy' websites either....but I have had visibility into the process behind the redesign for many of JPLs pages...and I can tell you, the demand for it isn't coming from designers, it's coming from management.


I'm reminded of the old issue where webpages would break if they detected you were on a phone:
https://imgs.xkcd.com/comics/server_attention_span.png

... now they apparently will just assume so.

Posted by: Bjorn Jonsson Apr 30 2015, 12:40 AM

QUOTE (JohnVV @ Apr 29 2015, 06:59 PM) *
...i DO find that the MOST useful sites ( content wise) look like this
a FTP page for the dawn spice kernels


Yeah - I usually get happy when I find something like this (SPICE kernels, IMG files or stuff like that).

QUOTE (Habukaz @ Apr 29 2015, 08:46 PM) *
Following up on that image, is the relatively crater-free area above the crater in this crop part of a massive landslide? Have we observed something similar on other bodies? The crater floor also appears to be of a relatively young age.


I'm not sure about landslides outside of craters (and this may or may not be a landslide, it will be very interesting to see higher res images of this terrain) but of course big landslides inside of craters are quite common, for example I remembered this one on Iapetus: http://photojournal.jpl.nasa.gov/catalog/PIA06171

Posted by: volcanopele Apr 30 2015, 01:25 AM

Reminds me a lot of the terracing on relatively fresh, large lunar craters like Tycho, so the stuff above it could be ejecta.

Posted by: elakdawalla Apr 30 2015, 03:42 AM

It really does look strikingly lunar.

Posted by: Phil Stooke Apr 30 2015, 08:05 AM

I can't say that area above the crater looks like a landslide to me, but if it is, there is a very good precedent. Look at the lunar farside crater Tsiolkovsky... on its northwestern side, a massive and clearly delineated landslide or debris flow extends down into an older crater.

Phil


Posted by: pitcapuozzo Apr 30 2015, 05:42 PM

Another view of the southern hemisphere! http://photojournal.jpl.nasa.gov/jpegMod/PIA19321_modest.jpg

 

Posted by: Gladstoner Apr 30 2015, 08:00 PM

Compared with the north polar area, there seems to be a paucity of small to medium sized craters, but more larger craters.

Perhaps the viewing angle due to Dawn's closer proximity may have something to do with it.

Posted by: fredk Apr 30 2015, 10:32 PM

More puzzling image release quirks: PIA19319 is reflected, as you can see by comparing the two new releases:


Posted by: djellison Apr 30 2015, 11:05 PM

QUOTE (fredk @ Apr 30 2015, 03:32 PM) *
More puzzling image release quirks: PIA19319 is reflected


I don't see reflection between those two images.

Posted by: Gladstoner Apr 30 2015, 11:37 PM

If the modified terrain is an ejecta sheet, then where is the basin? It could be the feature marked in red (on a portion of the global map):



(Edit: May not be a double ring due to Ceres' low mass.)

The complex crater prominent in image PIA19319 (first of recently released) is marked in purple.

The extent -- more or less -- of the ejecta sheet (or 'ejecta sheet') is marked in yellow.

Seemingly radial valleys are marked in white.

The map again, with no markings:



Another view of the 'ejecta' region and complex crater:



Since the 'ejecta sheet' is relatively pristine, we may soon see a large, beautifully preserved basin.

Posted by: fredk Apr 30 2015, 11:55 PM

QUOTE (djellison @ May 1 2015, 12:05 AM) *
I don't see reflection between those two images.

I reflected PIA19319 for that image (but not PIA19321) - compare it with the original version on the site.

Posted by: Astro0 May 1 2015, 12:42 AM

They must have fixed it. smile.gif

Here's the comparison between PIA19319 and PIA19321 as pulled from the Planetary Photojournal website.





Posted by: fredk May 1 2015, 03:09 AM

That was quick! But you can still see the reversed version http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA19319

Posted by: JohnVV May 1 2015, 03:52 AM

the other day i did notice a issue with the jpg's and the tif's
they were upside down to each other
( like how fits images open from the BOTTOM and tif's from the top )

Posted by: Astro0 May 1 2015, 06:06 AM

QUOTE (fredk @ May 1 2015, 01:09 PM) *
That was quick! But you can still see the reversed version http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA19319


Yeah, the one on the main page is reversed but the version of the photo from the link is the correct orientation. Strange. blink.gif


Posted by: Phil Stooke May 1 2015, 06:30 PM

A third south polar view was just released:

http://dawn.jpl.nasa.gov/multimedia/images/image-detail.html?id=PIA19322

This image is a composite of all three showing how they fit around the pole - this is only a rough alignment of images, not a map projection, and it's just to give an idea of coverage.

Phil


Posted by: Gladstoner May 1 2015, 07:33 PM





Just sayin'.... smile.gif


Posted by: Sherbert May 1 2015, 08:36 PM

Returning to the infamous SPOT 5 (3 spots). Very puzzling, but lots of zooms and upscaling later the scenario I imagine is the mound in the centre of the crater has somehow had two deep valleys gouged into opposite sides, exposing a brighter, presumably high ice content, sub surface below. The problem is I can't come up with a process or mechanism that would create such deep, but broad valleys. Possibly geysers venting from the side of the central mountain have carved the valleys, possibly a massive land slip along the lines of Mt St. Helens, erosion due to a melting pocket of ice maybe in the original impactor. I'm sure other plausible scenarios are available, these are just for starters.

EDIT: Maybe they are glaciers?

Once again drawing conclusions from images infuriatingly not quite at the required resolution is hazardous, but I thought I'd add my two pence worth.

Posted by: JohnVV May 1 2015, 08:44 PM

reposting a image i posted on a different forum
on May4 dawn will get a good look at that spot
http://imgbox.com/qBlFeqIP http://imgbox.com/3LbuNxCH
as it is spiraling into a LAMO from the HAMO

Posted by: Habukaz May 1 2015, 08:59 PM

Any observation on 4 May will have nothing to do with LAMO/HAMO. wink.gif

I don't recall having seen it explicitly stated that they'll take images during the downward spiralling, though I guess they could be valuable for navigation?

Posted by: scalbers May 1 2015, 09:26 PM

They do mention making observations on May 3-4, and I gather this continues in RC3 (a circular mapping orbit) that is above HAMO. I followed several status and journal links starting here:

http://dawn.jpl.nasa.gov/mission/status.html

"Dawn will observe Ceres as it flies from 45 degrees to 35 degrees north latitude on May 3-4. Of course, the camera’s view will extend well north and south of the point immediately below it. (Imagine looking at a globe. Even though you are directly over one point, you can see a larger area.) The territory it will inspect will include those intriguing bright spots. The explorer will report back to Earth on May 4-5. It will perform the same observations between 5 degrees north and 5 degrees south on May 5-6 and transmit those findings on May 6-7. To complete its first global map, it will make another full set of measurements for a Cerean day as it glides between 35 degrees and 45 degrees south on May 7."

Posted by: Gladstoner May 1 2015, 09:29 PM

Even though the image releases has been limited, is there information (i.e. times) available on all images that have been acquired so far?

Posted by: Habukaz May 1 2015, 10:10 PM

QUOTE (scalbers @ May 1 2015, 11:26 PM) *
They do mention making observations on May 3-4, and I gather this continues in RC3 (a circular mapping orbit) that is above HAMO. I followed several status and journal links starting here:



According to the table http://dawnblog.jpl.nasa.gov/?p=2437#names, RC3 does indeed go all the way through 9 May, I forgot to check that detail. The e-mail from Christopher Russel included http://www.nbcnews.com/science/space/dwarf-planet-ceres-white-spots-return-dawns-new-video-n344981 mentions the possibility to get better photos of the brightest spots in May:

QUOTE
UCLA's Christopher Russell, principal investigator for the Dawn mission, sent along this follow-up email:

"I have nothing to add to Carol's comments besides the fact that the small size of the bright spots resulting in our inability to resolve them is as agonizingly frustrating to the science team as it is to the public following the progress of our mission. The data coming down in May will have better resolution, but we still cannot guarantee it will be good enough to unambiguously determine the source of these mysterious bright spots. Argh..."

Posted by: Steve G May 2 2015, 12:09 AM

It's interesting to see the number of crater pairs. Similar size and shaped craters side by side.


Posted by: Explorer1 May 2 2015, 01:23 AM

The result of the presence of plenty of binaries in the main belt, presumably?

Posted by: Hungry4info May 2 2015, 01:27 AM

Asteroid binaries aren't restricted to radius ratios near unity.
I suspect this is more likely to just be the brain overestimating the statistical significance of some perceived correlation. If you're looking for crater pairs like that, you'll see them pretty much anywhere.

Posted by: TheAnt May 2 2015, 11:18 AM

QUOTE (Explorer1 @ May 2 2015, 03:23 AM) *
The result of the presence of plenty of binaries in the main belt, presumably?


I thought so too for a second, then realised that the asteroid pairs would have to be very nearly equal size.

With that idea quickly put in the wastebasket I rather think we see quite a number of craters of this size since such asteroids are fairly common.
In the same image we also got some larger craters, which have obliterated a lot of other craters of all sizes, some even overlapping.

If it wasn't for that fact I guess one could have counted craters to reverse engineer what asteroids Ceres have swept up from the orbit it got in the asteroid belt. =)

Posted by: Sherbert May 2 2015, 12:02 PM

Part of the IAU definition of a planet is that it sweeps its orbit clear (simplistically). Ceres does seem to have done an awful lot of sweeping. I thought it looked severely battered from the February images, but now we see its more crater than surface, especially in the polar regions. I wonder which post grad is going to get the short straw of cataloging them, a particular form of OCD might be required.

Posted by: Julius May 2 2015, 07:41 PM

Given all the hype about water detection at Ceres prior to Dawn's arrival in orbit, I am surprised at the extent of cratering present on this dwarf planet. I expected it more perhaps to look like Jupiter's Europa rather tHan resembling Earth's moon.

Posted by: Gerald May 3 2015, 01:58 PM

QUOTE (Phil Stooke @ May 1 2015, 07:30 PM) *
A third south polar view was just released:

http://dawn.jpl.nasa.gov/multimedia/images/image-detail.html?id=PIA19322

This image is a composite of all three showing how they fit around the pole - this is only a rough alignment of images, not a map projection, and it's just to give an idea of coverage.
...

Here my preliminary try to align projected versions:

Assuming the following globes for Dawn's Ceres images RC3 PIA19319.tif, PIA19321.tif, and PIA19322.tif
http://imgur.com/IUKHi22 http://imgur.com/0vif0qz http://imgur.com/qjXLjoo

south-polar projected versions
http://imgur.com/Mkyt6TU http://imgur.com/Ivmwwsw http://imgur.com/kfT3zjf

longitude/latitude rectangular projected versions
http://imgur.com/4SLkGNQ http://imgur.com/la2zgc1 http://imgur.com/AGD7N68
(roughly consistent with http://www.mpg.de/9003969/zoom.jpg).


Posted by: Gerald May 3 2015, 01:59 PM

and north-polar projected versions:
http://imgur.com/sozgjRq http://imgur.com/VxZ9M0K http://imgur.com/vHt6RmF

Posted by: wildespace May 3 2015, 06:23 PM

Those are fantastic images we're getting now. Ceres looks like a mini-Moon

I have a humble request for you very talented people on this forum: could someone please use the recently-released colour map of Ceres in spherical projection, and overlay it on the images we receive, so that we would see the surface in its approximate true colours:



Thanks smile.gif

Posted by: scalbers May 3 2015, 06:32 PM

It would indeed be nice to augment any newer hi-res black and white maps with color information from the enhanced false color map that has been released. However the color map is very much departed from true color and isn't a simple conversion.

BTW I'd be interested to add some of these latest maps to Science On A Sphere if that would be OK.

Posted by: Gerald May 3 2015, 07:40 PM

Here versions colorized with the map wildspace provided:

http://imgur.com/6sjpkXq http://imgur.com/ADXrDWK http://imgur.com/ZEfnCf1

Since the color map is partially almost white, colors are saturated at those areas, with limited semantics.

You may use at least my maps under the same conditions the according pia images are provided.

Posted by: Habukaz May 4 2015, 01:58 PM

Gerald's projections makes it is easier to see that the zig-zag linear features in or near the big crater that I http://www.unmannedspaceflight.com/index.php?s=&showtopic=7960&view=findpost&p=218666 earlier seem much more real now (RC2 to the right).




It also looks like this crater could be quite pretty in higher-resolution images (valleys? cliffs? varied terrain inside the crater? etc.).

Posted by: Habukaz May 4 2015, 05:01 PM

http://photojournal.jpl.nasa.gov/catalog/PIA19323, this one also it shows the previously mentioned big crater. Now, my compass orientation is getting mightily confused by the latest image releases, but I guess we're seeing the second big basin in this image, east of that other big one:


Posted by: Phil Stooke May 4 2015, 05:15 PM

"It also looks like this crater could be quite pretty in higher-resolution images (valleys? cliffs? varied terrain inside the crater? etc.)."

All we need now is a few gullies!

Phil


Posted by: Gladstoner May 4 2015, 07:22 PM

QUOTE (Phil Stooke @ May 4 2015, 12:15 PM) *
All we need now is a few gullies!


There are gullies. smile.gif


Posted by: ZLD May 4 2015, 07:50 PM

The gully in the latest image is really interesting! Hopefully we can see some remnant of a cryovolcano at the head of it. Would certainly help in pinning down what they can look like.

Posted by: Gladstoner May 4 2015, 09:18 PM

The curving or otherwise non-linear nature of the valleys is intriguing.

Just as interesting -- and apparently associated with the valleys (?) -- is the widespread resurfacing with few craters. It does look like a fairly fresh ejecta sheet, but there doesn't seem to be a source basin nearby.

Posted by: Gladstoner May 4 2015, 10:23 PM

The rough patch of ground here ( from 1st of 4 recent images) almost appears as if it has been tilled.



Can't wait until the higher-res photos....

Posted by: dvandorn May 5 2015, 03:40 AM

Now, that looks like an ejecta sheet to me. Why? Because, if you look closely, there are buried craters underneath this "tilled" terrain, ghost-like impressions of craters that seem to have formed a rugged surface like that which borders on the ejecta sheet, but has been filled in and covered by the ejecta. The contrast of fresh, well-formed craters to the ejecta sheet is obviously different from similarly sharp craters on the adjoining non-sheet-covered surface. The ejecta itself is grooved (the "tilling" effect) along the direction of flow, which seems to pile up in the side of the large crater that has been noted as looking as if the floor has a landslide in it.

Again, there are similar features on the near side of the Moon, including the Fra Mauro formation, which appear very similar, and which are ejecta sheets emplaced by basin-forming impacts. The similarities are so compelling to me that this is a no-brainer, I think.

-the other Doug

Posted by: Gladstoner May 5 2015, 04:23 AM

Again, what is the source of the ejecta? The imaging coverage isn't yet ideal, but there doesn't seem to be an obvious, fresh basin nearby. That one large basin was revealed today, but it seems to be pretty subdued to be a source for such fresh ejecta:



Maybe it's the less than ideal lighting.

Interesting stuff nonetheless....

Posted by: Phil Stooke May 5 2015, 09:34 AM

It's right next door to its basin (left edge)! And there is another much more subdued but even larger basin at top center in your cropped image. Besides, on a small object like Ceres basin ejecta can cover a hemisphere, it doesn't need to be that close.

Also, don't be taken in by the 'fresh' appearance of the ejecta. Look at the ejecta of Orientale on the Moon. Old but remarkably fresh-looking.

Phil

Posted by: TheAnt May 5 2015, 10:28 AM

QUOTE (Gladstoner @ May 5 2015, 12:23 AM) *
The rough patch of ground here ( from 1st of 4 recent images) almost appears as if it has been tilled.


Same here, first I thought the rough patch was ejecta that had been thrown out at the impact, but looking at the part inside the crater I settled for the idea that it have moved into the crater, and might be in the process of filling it in at least partially.

Together with the gullies it appear that we spotted some of the processes I hoped we would find at Ceres, there might be more to come at higher resolution. =)

Posted by: RotoSequence May 5 2015, 05:09 PM

Holding steady at one image per day, RC3 image #5: http://dawn.jpl.nasa.gov/multimedia/images/image-detail.html?id=PIA19536

Posted by: ZLD May 5 2015, 05:43 PM

Some interesting features in RC3-5 (PIA19536).

In red: possibly a fault line that has caused a ridge? Edit: appears to be a long fault line running up and right away from the ridge. Looks like the ridge cut off a small section of this longer fault as well.
In blue: possibly a gulley like feature? Edit: looking at this again, may be more likely related to what caused the large crater shortly before impact. A sort of grazing maybe?


Posted by: Gladstoner May 5 2015, 07:14 PM

QUOTE (Phil Stooke @ May 5 2015, 03:34 AM) *
It's right next door to its basin (left edge)! And there is another much more subdued but even larger basin at top center in your cropped image. Besides, on a small object like Ceres basin ejecta can cover a hemisphere, it doesn't need to be that close.

Also, don't be taken in by the 'fresh' appearance of the ejecta. Look at the ejecta of Orientale on the Moon. Old but remarkably fresh-looking.


I've been straining to interpret the stuff as ejecta and other impact effects, but some things seem 'off'.

- The 'tilled ground' seems to have an irregular or even patchy distribution. The edges appear abrupt in some cases. Ejecta usually grades into the surrounding terrain in a regular manner -- or so it seems/appears, at least.

- There are no obvious source basins for the ejecta/tilled ground. Nearby candidate craters/basins are either partially covered in the stuff, or appear too old or degraded. I was eagerly awaiting to see a dramatic basin on the image released on May 4, but instead was disappointed by a barely visible outline.

- The crater size distribution is odd. I would expect more small- and medium-sized craters on ejecta from a degraded basin.

- Speaking of crater size distribution, I'm still amazed by the number of large craters around the south pole. What 'happened' to all the smaller ones (that seem to 'prefer' the north pole)?

- The curved valleys are a surprise. I would expect straight valleys (grabens or crater chains) on a primitive body like Ceres. Slumping causes curved grabens, but that doesn't seem to be in play here. My eyes even see 'spiral' patterns of valleys surrounding a couple basins, but more imagery is needed to address that....

- I look forward to more puzzling questions in the coming days, weeks and months.... smile.gif

Posted by: Ken2 May 5 2015, 10:10 PM

QUOTE (ZLD @ May 5 2015, 09:43 AM) *
Some interesting features in RC3-5 (PIA19536).

In blue: possibly a gulley like feature? Edit: looking at this again, may be more likely related to what caused the large crater shortly before impact. A sort of grazing maybe?


I think you are on to something. My armchair guess is the large crater was first and a second oblique impact (blue oval) came in and blew out the crater wall and sent the ejecta curtain over the far side of the crater. Many oblique impacts can make lateral butterfly ejecta patterns, but hitting/digging out the crater wall is a unique scenario and might allow for a larger downstream ejecta curtain.

Posted by: Gladstoner May 5 2015, 10:12 PM

QUOTE (Gladstoner @ May 4 2015, 05:23 PM) *
The rough patch of ground here ( from 1st of 4 recent images) almost appears as if it has been tilled.



On second thought, the 'tilled' surface inside the crater may not necessarily be related to the surrounding 'tilled ground'.

The outer area could be ejecta, while the inner stuff could have resulted from a slide of the crater rim:



The textures of the two area happen to be similar in appearance -- at least at the current resolution.

Posted by: Gladstoner May 6 2015, 07:00 PM

New image: PIA19538: Dawn RC3 Image 6

http://photojournal.jpl.nasa.gov/catalog/PIA19538

The terrain on the left reminds me of Mars.


Posted by: antipode May 6 2015, 10:15 PM

Is that a big central peak peering over the limb at left, or something else?



P

Posted by: Gladstoner May 7 2015, 12:06 AM

QUOTE (antipode @ May 6 2015, 05:15 PM) *
Is that a big central peak peering over the limb at left, or something else?


It could be the thing circled in yellow:


Posted by: Habukaz May 7 2015, 04:13 PM

A http://photojournal.jpl.nasa.gov/catalog/PIA19540 from RC3 has been released, and we are still in the same general area as several other previously released RC3 images. I hope we get new sceneries soon (the flat crater, the other bright spots etc.). smile.gif

Posted by: Steve G May 8 2015, 04:12 AM

According to their Facebook page, at this Saturday's "i C Ceres Space Science Festival, more images will be released. They're probably saving the best for then - I hope.

Posted by: Habukaz May 8 2015, 04:27 PM

Now we got http://photojournal.jpl.nasa.gov/catalog/PIA19542. I think it includes at least two of the bright spot features (i.e. not spot(s) 5).

Posted by: Ken2 May 8 2015, 05:11 PM

New image has 2 blotches - the blue one in particular looks like dust on the lens, cosmic ray or more intriguing a mini moon? (it has the same look as those comet 67P/CG blotches)

The red one at first glance looks like a normal peak shadow - except the dark to light aspect of it is reversed from all the other shadows around it (and it looks like fairly flat terrain - though one can't be at all sure at this resolution and phase angle). Maybe another mini moon candidate, or a hole?



Posted by: ZLD May 8 2015, 05:47 PM

The red circled area looks like a barely resolved deep crater/sunken hole to me with the lower section black and in shadow and a very slight highlight just above it. The blue area is somewhat intriguing though. I would expect to see some sort of highlight on the lowest pixel if it were an orbiting object but it could just not have any angles reflecting toward the camera. Most likely noise though.

Posted by: Gladstoner May 8 2015, 07:17 PM

World Ceres!

Posted by: nprev May 8 2015, 07:44 PM

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

Posted by: Gladstoner May 8 2015, 07:58 PM

Is the latest image true 1x1 aspect ratio? It may be my imagination, but Ceres here seems a bit stretched north-south. If I recall, the released February 19 rotation sequence was slightly stretched in such a manner.

Posted by: Gladstoner May 8 2015, 10:25 PM

QUOTE
Now we got http://photojournal.jpl.nasa.gov/catalog/PIA19542.


After a bit of staring.... The north pole is at mid terminator at the top - FYI.

Posted by: Gladstoner May 8 2015, 11:06 PM

A thought....

There appears to be a number of broad depressions with soft edges scattered all over the surface that remind me of grabens. For a lack of a better term, I've nicknamed them 'soap dishes'. A few of these are contained within large craters and basins, possibly with associated 'mounds' (horsts?).

Having said that.... In the latest image, a crater with a bright wall appears to be on or near the rim of one of these 'soap dishes' (in the large crater on the left). Is this association coincidence, or could this be a clue to whatever processes produced the bright areas here and elsewhere?

If these 'soap dishes' are grabens, the long rim of one would mark a fault in the crust. Such a fault (fracture zone) could potentially serve as a conduit for material rising from below at any time, even if the graben itself is extremely ancient. The material movement likely would have happened in the distant past as well, though.

Posted by: wildespace May 10 2015, 08:41 AM

Catalogue entries for PIA19336 and PIA19337 have been reassigned to PIA19536 and PIA19537 respectively. Anyone got any idea why? They were listed in Emily's blog: http://www.planetary.org/blogs/emily-lakdawalla/2015/05051006-a-weeks-worth-of-rc3-dawn-ceres.html under their old designations, so I'm giving a heads up in case anyone will want to look for them again.

Posted by: Gladstoner May 10 2015, 10:49 PM

The feature here:



May be the same as this:


Posted by: belleraphon1 May 11 2015, 01:58 PM


RC3 May 4th Rotation
http://photojournal.jpl.nasa.gov/catalog/PIA19547

Posted by: jgoldader May 11 2015, 02:45 PM

QUOTE (belleraphon1 @ May 11 2015, 08:58 AM) *
RC3 May 4th Rotation
http://photojournal.jpl.nasa.gov/catalog/PIA19547


Well, they're resolved now! But... deposits?...or a snowball that went splat? blink.gif

Posted by: Floyd May 11 2015, 02:45 PM

Lots of little white spots showing up around the globe--not just next to the "two" big spots in region 5. Little white spots--whatever they are--are common on Ceres.

Posted by: Habukaz May 11 2015, 02:52 PM

Wow, there's a lot of stuff to take in in that animation. I note that it looks like the dark area to the east of the brightest stuff is back; which now looks a bit like it is asymmetrically centred on that crater.



And then of course, those long rifts - or whatever the appropriate terminology is.

Posted by: hendric May 11 2015, 02:57 PM

Yeah, I give up, I have no clue what the heck double-white-spot is. unsure.gif The closer we get, the weirder it looks!

Posted by: Phil Stooke May 11 2015, 03:15 PM

My version of this new image. The 'rifts' look a lot more like secondary crater chains to me.

Phil


Posted by: Habukaz May 11 2015, 03:28 PM

Looking at them again, that explanation makes sense. They look like rifts/valleys when they are on the right hand side of the frame (like in the image below), and then appear to dissolve/disappear when are on the left, so maybe the rift-like appearance is caused by a deceiving viewing angle.


Posted by: elakdawalla May 11 2015, 03:29 PM

Some of those "rifts" look a lot like those on Rhea -- I forget what the current thought is on those, are they thought to be secondaries? (Paul Schenk, are you lurking here?)

Posted by: MarsInMyLifetime May 11 2015, 03:31 PM

QUOTE (hendric @ May 11 2015, 09:57 AM) *
Yeah, I give up, I have no clue what the heck double-white-spot is. unsure.gif The closer we get, the weirder it looks!

The off-center 'dot' now has a constellation of smaller surrounding dots, and the central dot now has two components (see attachment). So along with the dark, asymmetric pattern to the side, I'm inclined to look at this as a very recent strike from a broken object, but this does not align with the purported elevation reports.


Posted by: Bjorn Jonsson May 11 2015, 03:46 PM

QUOTE (jgoldader @ May 11 2015, 02:45 PM) *
Well, they're resolved now! But... deposits?...or a snowball that went splat? blink.gif
This still looks like exposed ice to me but why the ice should be exposed in this crater and not also in lots of other craters is a mystery if I'm correct. There also seems to be a 'fainter' bright spot below the bright spot at right - the black line in the attached image points at it. This might be ice that's more dirty or ice (partially?) covered by a thin layer of darker material.




Posted by: dudley May 11 2015, 04:08 PM

The shapes of the bright spots still look blocky to me, as if not truly resolved. Their diameter, in proportion to the known size of the crater, appears much larger than expected for resolved objects. We were told that the bright spots were unresolved at 2100 meters per pixel, so their expected sizes were less than that. If the bright spots are resolved, then what are their true diameters?

Posted by: Paolo May 11 2015, 04:12 PM

according to Co-I Dr. Tom McCord http://www.seattleastronomy.com/blog1/2015/05/white-spots-on-ceres-may-be-salt/

Posted by: fredk May 11 2015, 04:23 PM

If this is an icy body strike, then you still have the coincidental location so close to the centre of a crater unexplained.

Looking at this frame, to me it looks like the brightest part of region 5, the part near the crater centre now resolved into two spots, might be located on the face of a scarp that runs around to the crater rim (arrowed):


As you follow the animation around, the scarp becomes less visible as the crater approaches the opposite limb, which may be consistent with a topographic feature (ie, scarp) rather than an albedo feature. And the bright spots being located on a slope could explain brightness variations of the spots that have been discussed.

Posted by: Bjorn Jonsson May 11 2015, 05:20 PM

I don't think this could be only due to topography (the difference in brightness is too big when the crater is viewed from above). But some combination of topography and albedo is a possibility and indeed seems likely when looking at the images that show the bright features close to the limb.


Posted by: Ken2 May 11 2015, 05:31 PM

QUOTE (Ken2 @ May 8 2015, 09:11 AM) *
New image has 2 blotches - the blue one in particular looks like dust on the lens, cosmic ray or more intriguing a mini moon? (it has the same look as those comet 67P/CG blotches)

The red one at first glance looks like a normal peak shadow - except the dark to light aspect of it is reversed from all the other shadows around it (and it looks like fairly flat terrain - though one can't be at all sure at this resolution and phase angle). Maybe another mini moon candidate, or a hole?





Oh well - the blotches turns out to be in every image in today's rotation movie - the two blotches are at the same separation - just moved around depending on the frame. Camera artifact / dirt. There's also a third artifact (dark circle down left of the blue botch). It was fun while it lasted smile.gif


Posted by: Gladstoner May 11 2015, 05:55 PM

This is a heck of a mountain:


Posted by: Floyd May 11 2015, 06:10 PM

There are many small white spots scattered around the globe that were not resolvable in earlier images. In addition to the newly resolved small white spots in the region 5 crater, there are similar small spots in other craters. For example, if north is up (most likely not) then then there is a small white spot at 12 o'clock in the crater one region 5 crater diameter to the ESE. Just a bit north of 80% of the way east to the terminator, there is a spot in a crater within a crater at 10 o'clock. A little more than 90 degrees west of the region 5 crater is large crater with several small spots and streaks. Whatever these white spots represent, there are examples in several places other than region 5. Lets look beyond just one particularly eye candy crater...

Posted by: ZLD May 11 2015, 06:12 PM

Interesting looking feature extending from the surface.


Posted by: pitcapuozzo May 11 2015, 06:23 PM

According to the flight plan (if I understand it correctly), on May 9th Dawn should have left RC3 and started spiraling down, heading towards Survey Orbit (4400 km above ground, 410 meters/pixel, 3x RC3's resolution and 72x Hubble's resolution). Dawn should reach Survey Orbit on June 6th. Do we have any confirmation of Dawn having departed RC3?

Posted by: fredk May 11 2015, 06:25 PM

QUOTE (Gladstoner @ May 11 2015, 06:55 PM) *
This is a heck of a mountain

Very roughly 4 km high.

Posted by: Gladstoner May 11 2015, 06:42 PM

A possible scenario comes to mind....

- In the distant past, fluids rose through the crust (i.e. 'volcanism') in scattered places via fractureres/faults.

- Salty deposits were left behind along the conduits as intrusive deposits, possibly as swarms of mineral veins. The frequency of these may increase with depth. Some of the 'brine' may have erupted onto the surface.

- Subsequent impacts and other erosive processes have cause exposed salts to fade over time and blend in with the surrounding drab surface. Unfortunately, there may be no extrusive deposits remaining (if there ever were any).

- In a few cases, a fortuitously placed impact or landslide could expose some of the deposits. In the case of spot #5, perhaps the central uplift tapped into a particularly large deposit of salt and drew it closer to the surface. The brightest area may be due to (relatively) recent landslides (edit: and/or impacts) on the central peak. Some of the surrounding smaller spots could be more exposures of the same deposit, or landslide debris from the peak.

Edit: For comparison, Phoebe provides some examples of landslide exposures of patchy (relatively) bright material:


Posted by: pitcapuozzo May 11 2015, 07:22 PM



Just another image of the 4? km high mountain.

Posted by: Gladstoner May 11 2015, 07:25 PM

The area corresponding with Piazzi:



The dark mottling isn't as obvious here, but there are a few tiny bright spots.

Posted by: Gladstoner May 11 2015, 07:52 PM

Bright spots: a family portrait:



Image 3 features the large mountain (bottom spot).

Posted by: MarsInMyLifetime May 11 2015, 08:02 PM

It may soon be time for some underexposed frames that shift the washed out zones into the gray scale for analysis. Given that there seems to be some sensible scale to the size of some of these dots, any detail or sense of relative brightness between them is still washed out.

Posted by: Habukaz May 11 2015, 08:04 PM

There's also this feature that looks like a three-pronged mountain:



Posted by: Zelenyikot May 11 2015, 09:36 PM

It look like volcano


Posted by: Phil Stooke May 11 2015, 09:59 PM

Wow, that is really good! Thanks.

Phil

Posted by: ZLD May 11 2015, 10:15 PM

I'd say its a good candidate for a volcano like feature. If you watch closely to the first few frames, you can see what would appear to be a depression in the top center of the mound.

Added some deconvolution sharpening.
http://i.imgur.com/q1SMqJH.gif
(click to animate)

Posted by: Bjorn Jonsson May 11 2015, 10:16 PM

QUOTE (Zelenyikot @ May 11 2015, 09:36 PM) *
It look like volcano


Very interesting feature and a really cool animation. The mountain apparently has some albedo features but I also get the impression that some of the bright features are at least partially due to illumination geometry changes.


Posted by: Sherbert May 11 2015, 11:23 PM

To take stock after the RC3 images. In addition to huge numbers of craters, there appear to be sundry other features, gouges, plateaus, basins rough and smooth and gullies. There are a large number of "polygonal" craters mainly pentagons and hexagons, which should tell those who know about such things something about the composition of the surface layers. There appear to be "stretch marks", which either indicate tectonic activity or are the result of expansion and/or contraction in the past. The numerous bright spots all appear to be of indigenous origin from their shapes, possibly as Gladstoner suggests from seepage of material from below the surface. THE bright spots have the appearance of salt lakes and the odd "spiky" shapes of a couple of other spots suggest they too are the result of fluid deposition. The fascinating mountain is most probably a volcano, since other mountain building scenarios seem in short supply in this area, that is, its not a central peak in a crater or the remains of a crater rim. I just wonder if it is not a giant "Iceberg" that has been thrust up through the surface from below, just to introduce a left field possibility. Different densities and phases of water ice might lead to odd occurrences such as that.

So lots to ponder on still and still we require better resolution. Dawn is due to take a couple of sets of images as it spirals into the next survey orbit, we await further enlightenment.

Posted by: Gladstoner May 12 2015, 01:19 AM

Speaking of left field ( smile.gif ) ....

I can't help but be reminded of Middle Butte near Idaho Falls, Idaho:



When I saw this butte some years ago while traveling through the area, I figured it was a cinder cone (one of several along the Snake River valley). As it turns out, though, Middle Butte formed when a volcanic intrusion pushed up the overlying rocks in a piston-like fashion.

The mountain on Ceres has a roughly similar appearance -- isolated, with (mostly) steep slopes and (an apparently) flat top. Since there is a lack of obvious geologic context here, I figure this is either a volcanic (or 'volcanic') construct or a tectonic uplift. Since it is hard to imagine sustained eruptions producing a 4 km high edifice on Ceres, I'm leaning toward an uplift of some kind.

If this is a tectonic uplift, it may provide a valuable cross section of the upper crust. When I strain my eyes while watching the animations, I think I can just make out a sandwich-like structure in the slopes, i.e. bright-dark-bright. These variations of albedo are probably a combination of outcrops and talus/debris. Since there appears to be some of the high-albedo material present, this could help sort out its nature and origin.

Also, the steepness of the slope on the mountain's north face may be partially due to the impact crater just below it.

Posted by: MarsInMyLifetime May 12 2015, 03:10 AM

I have to agree that this hill is volcano-like in appearance. But if it is due to a geologic process, then why, over geologic time, haven't many others also appeared? Perhaps this one is unusually large and the others are lurking just below the present limit of resolution... more geyser-like in form than built up from durable "ash." What I'm missing so far in the surface is a sense of history of repeating processes (as in Europa's criss-crossing ice ridge sequences).

Posted by: Habukaz May 12 2015, 09:33 AM

It's certainly a very interesting-looking feature. It might be related to what was mentioned by a project scientist in a http://www.seattleastronomy.com/blog1/2015/05/white-spots-on-ceres-may-be-salt/ posted earlier:

QUOTE
There are domes, things pushing out from the inside,” he continued, “and bright spots that suggest that material from inside has come to the surface in some sort of volcanism.”


If the feature is caused by internal geological processes, there might be more of them. This might be the one that grew the biggest, it might be the youngest one or it might be the one that is the most resistant to erosion.

Posted by: Webscientist May 12 2015, 10:31 AM

Well found!

I've performed a rough calculation based on the perspective of this view and I obtain a diameter of the mountain/volcano (from left to right) of 18.52 km.

(16 px / 842 px *974.6 km = 18.52 km.)



 

Posted by: ZLD May 12 2015, 02:57 PM

Heres another way of viewing the mound in RC3. Centered and rotated the frames to reproject a flyover of the area. The mound appears to be sitting on either highlands or an uplift of some sort. Interesting!

Posted by: fredk May 12 2015, 03:12 PM

QUOTE (MarsInMyLifetime @ May 11 2015, 09:02 PM) *
It may soon be time for some underexposed frames that shift the washed out zones into the gray scale for analysis. Given that there seems to be some sensible scale to the size of some of these dots, any detail or sense of relative brightness between them is still washed out.

In frame 15 the solar illumination is at a very low angle and the region 5 spots are apparently not overexposed. However, if you carefully align frames 15 and 16 (this involves rotation as well as squashing the minor axis of the crater in frame 16), it looks like the morphology of the brightest part (in the centre of the crater) changes:

In particular, frame 15 shows the central part clearly resolved into two spots, but in frame 16 it looks like a new bright spot/region has appeared just to the right of the two central spots. If the two spots were simply getting brighter as the sun rose, and hence overexposing and getting larger due to the brightening of the tails of the PSF, then the two central spots in frame 15 should simply get brighter and larger and eventually merge into an elongated shape. Instead, we see what looks like a third central spot/region.

One possibility here is an actual change on the surface, with a new bright region turning on due to solar heating (I think we heard some speculation about this earlier from the team). But perhaps it's more likely that this is simply due to topography: the third central spot is in shadow in frame 15 and in sun in frame 16. We had hints of this in previous releases.

(Like usual, we need to be careful about pixel-scale details, although here we're clearly signal-dominated.)

Posted by: alk3997 May 12 2015, 03:52 PM

Could the change in frame 16 just be the result of the CCD sensor becoming saturated? It looks to me that the brightness has increased significantly between frames 15 and 16 and therefore frame 16 no longer resolves the individual points.

Andy

Posted by: fredk May 12 2015, 04:23 PM

Definitely they get brighter, but they also develop a "bump" off centre, indicated by the intersection of the white lines:


This is the puzzling thing. Conceivably CCD bleeding could do this, but if it was bleeding there's no sign that the bleeding gets worse (longer) as you'd expect as the spots move further into the sun and brighten considerably.

Posted by: ZLD May 12 2015, 05:27 PM

Made a flyover for 'Spot 5' as well.
http://i.imgur.com/92iruXN.gif
(click to animate: 4mb)


Not able to tell but looking at the smaller white areas in this perspective, makes them appear as if they have some sort of volume to them as if they were a plume, especially the upper left one. Did they rule this out yet?

Edit: Looking at this more (I feel mesmerized) the crater floor has been resurfaced at some point as well. There also appears to be some rays around the largest spot, which I thought was maybe ejecta at first, but they appear to come as go with the light. Strange. Whatever these objects are, you can definitely see the suns glint travel across them as the camera follows.

Edit 2 (5-13): For anyone wanting/needing a more focused look at the spot, I cropped and resampled this image.

Posted by: pitcapuozzo May 12 2015, 05:30 PM

Do we have any albedo information at this point on the bright spots? I read it was something like 0.12, but that was a long time ago.

Posted by: Gerald May 12 2015, 05:44 PM

The bright spots should be much closer to albedo 1.

Posted by: Ken2 May 12 2015, 06:06 PM

I'll admit the new images are perplexing of spot 5. however based on the other white spots I'm still firmly in the impact exposing ice/salty ice hypothesis camp.

In any event I made another movie of the first 6 images as the spot comes into view. I still think we are seeing the side of a crater getting illuminated and the crater reflecting more and more and appearing bigger and bigger.

As for all the new little white spots - who knows - but Ceres is clearly a body dominated by cratering, and this crater is crater upon crater upon crater - so with that in mind - I think I can trace a few old rims and the little white spots might be the edges of some of them. I have a very rough guess at where some of them might be (can't wait for higher res picts!) in the image - the crater lines are probably off - but it show the gist. Now as for why the edges of the craters are white? Maybe the main impact caused shrapnel scraping the tops off or dusting the tops with ice.

Click to animate GIF


Posted by: Gerald May 12 2015, 06:52 PM

Another mechanism, I could imagine, are landslides (triggered e.g. by physical weathering / thermic cycling) at steep slopes exposing fresh (not yet darkened) material.

Posted by: ngunn May 12 2015, 09:03 PM

QUOTE (Ken2 @ May 12 2015, 07:06 PM) *
I'm still firmly in the impact exposing ice/salty ice hypothesis camp.


I find myself in that camp too, although there are well placed scientists invoking volcanic processes so I don't know. . . It's easy to imagine an impact triggering landslips nearby so maybe that's what we're seeing in some places at least.

Posted by: jgoldader May 12 2015, 09:41 PM

Looking at the animation for spot 5, I'm tempted to see the spot at the crater's center as being a depression. On both the right and left sides of the white spot, in the image, there appears to be a ridge or crater rim a couple of pixels high.

I would think it was a fresh crater that had penetrated into a watery/icy region, then filled up with fresh ice, but why is that tiny spot so conspicuous on the entire asteroid? Why just the one place? The rest of Ceres is so battered, it would make more sense to me if there were many things like spot 5. I know there are some bright areas, but 5 really jumps out.

Posted by: Gladstoner May 12 2015, 10:10 PM

QUOTE (jgoldader @ May 12 2015, 03:41 PM) *
but why is that tiny spot so conspicuous on the entire asteroid? Why just the one place? The rest of Ceres is so battered, it would make more sense to me if there were many things like spot 5. I know there are some bright areas, but 5 really jumps out.


To me, that is what is most intriguing about it. If it is merely bright stuff beneath the regolith, I'd expect something more like Callisto.

Posted by: Gladstoner May 12 2015, 10:28 PM

Just trying to map out the bright areas:


Posted by: Gladstoner May 13 2015, 06:51 AM

Crater floor fractures?




Posted by: antipode May 13 2015, 10:31 AM

Is that rift in any way radial to the mountain/'volcano' thingy? Could they be associated?



Why am I thinking Tharsis?

P

Posted by: 0101Morpheus May 13 2015, 10:39 AM

Too soon to tell unfortunately. Impacts can create rifts too, and Ceres has had an awful lot of them.

Posted by: Phil Stooke May 13 2015, 12:30 PM

I don't know if I can think of a single example of an impact producing a rift. The grooves of Phobos are often cited as such, but that's a hypothesis, not a certainty, and other possibilities have been suggested (impact of Mars ejecta, jointing during excavation from a larger primary, or drainage between blocks in a rubble pile, for instance). The "Imbrium Sculpture" pattern of radial lineations on the Moon is now regarded as due to ejecta scouring and deposition, not structural in origin as suggested decades ago.

It's much more likely that this feature is a chain of secondary craters. Think Rima Schroedinger or the Rheita Valley on the Moon.

Phil

Posted by: John Broughton May 13 2015, 12:47 PM

Has anyone noticed in the RC3 movie, small hills (cones) at the bright spot near the large mountain, and that they and the mountain are both on a fault line, and that this system of faults extends through the crater with the brightest spots of all?

John


Posted by: tasp May 13 2015, 01:01 PM

The crater Turgis and the 'tiger scratches' on Iapetus came to mind as something to compare the rift on Ceres to. The association of the crater and the 'scratches' on Iapetus might be coincidental, and AFAIK, there seems to be only one rift seen on Ceres and IIRC, there are 3 'scratches' noted on Iapetus.

Posted by: Phil Stooke May 13 2015, 02:09 PM

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


Posted by: Gladstoner May 13 2015, 03:16 PM

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



These were visible in earlier images:



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.

Posted by: ZLD May 13 2015, 04:29 PM

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



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.


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 https://www.youtube.com/watch?feature=player_detailpage&v=lj3x2U4CaEs#t=106.

edit: terminology

Posted by: dvandorn May 13 2015, 07:13 PM

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?

Posted by: Bill Harris May 13 2015, 07:35 PM

Please, continue to discuss and speculate...

Posted by: Ken2 May 13 2015, 07:54 PM

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?






Posted by: Gladstoner May 13 2015, 08:04 PM

Piazzi (contrast enhanced):



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.

Posted by: TheAnt May 14 2015, 11:38 AM

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. =)

Posted by: Ken2 May 14 2015, 04:50 PM

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.

Posted by: elakdawalla May 14 2015, 05:48 PM

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.

Posted by: ngunn May 14 2015, 05:51 PM

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...




Posted by: Gladstoner May 14 2015, 09:23 PM

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




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:



Again, mere coincidence has to be assumed until more data comes in.

Posted by: RotoSequence May 14 2015, 09:56 PM

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):




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!

Posted by: alk3997 May 14 2015, 10:42 PM

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

Posted by: dvandorn May 15 2015, 12:47 AM

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...

Posted by: nprev May 15 2015, 01:03 AM

Just to step in with a mod opinion here: Speculation on new observations of a never-before-seen world is of course encouraged; that's half the fun! smile.gif

Please take time to review the Rules & Guidelines section, and let's keep it confined to the realm of the possible within realistic constraints. Also, please avoid rants & idee fixe's; those become very tiresome very quickly. Our intent as always is to increase the signal-to-noise ratio of the Forum, so please keep that in mind.

Thanks!

Posted by: John Broughton May 15 2015, 03:28 AM

QUOTE (Bill Harris @ May 13 2015, 07:35 PM) *
Please, continue to discuss and speculate...

There's enough evidence in the RC3 images to make some preliminary conclusions on the unusual features we see.

MOD NOTE: No, there isn't nearly enough evidence yet to draw conclusions. Currently there is an extremely limited amount of data which may be used to formulate very tentative hypotheses which will be accepted, revised or discarded based on additional evidence and critical review. Key difference.

EDIT: To avoid misinterpretation, the gist of what I failed to convey properly in my first line follows.

I see enough evidence in the RC3 images to comment on what I believe the unusual albedo features are and speculate on how they formed.

1. The extensive grooves represent deep cracks in the crust, rather than crater chains from secondary impacts.

2. The spots are volcanic cones associated with rift valleys and fault lines, rather than craters exposing more reflective material beneath. That should become obvious to all when Survey Orbit images are released in June. The vents gradually expel cold ocean water, as a safety valve to equalise the pressure caused by expansive freezing on the underside of the ice crust. The water oozes out and freezes or falls as snow, before sublimating and leaving permanent deposits of salt behind on the surface. The mountain visible since February appears to be the largest such structure on Ceres, but is dormant or extinct judging by the dust gathering on its summit. However, the brightest spot/s could well be active and have ice close to their vents - something on Ceres is producing enough water vapour to be detectable from Earth.

3. The dark patches of chaotic terrain are also associated with fault lines. They probably represent sudden flows of rock-bearing mud, flooding out when major impacts occur elsewhere on Ceres and oscillations in ocean water pressure force some plates to gnash and grind against each other. The grooves become indistinct there because of that flooding. The southwest rim of Piazzi crater and the northeast rim of 'bright spot' crater are obvious examples of this, but there are others in the southern hemisphere we haven't seen in detail yet. I won't be surprised if all such regions have grooved terrain and volcanic cones associated with them, because they represent areas where water can most easily reach the surface.

Posted by: Steve G May 15 2015, 05:53 PM

I come to this site every day and even though I have been a space enthusiest for 45+ years, I rarely make comments because of the high calibur of the regulars, I would have little to add!

Posted by: Habukaz May 15 2015, 06:31 PM

Dawn will pause its ion thrusting tomorrow to take navigation pictures of Ceres per the http://dawn.jpl.nasa.gov/mission/status.html. No mention of which areas of Ceres that will likely be photographed.

Posted by: Gladstoner May 15 2015, 09:38 PM

Speaking of 'fun' speculation, I'll give it a shot, with heavy emphasis on 'fun' at this point....

Some scientists have said there *may* be evidence of cryovolcanism on Ceres. If that turns out to be the case, then is it possible the darkish areas surrounding the bright spots could be plume deposits?:



I can't help but be reminded of these features on Triton:



(Some of these even have darkish material eminating from brightish spots.)

The materials and processes on Ceres would be quite different than those on Triton, though, and there would be no atmosphere on Ceres to carry the particles down wind. Extensions of a Cerean plume deposit in certain directions would likely be due to the configuration of the conduits and vents.

Again, the usual caveat: This 'theory' could very well be ejected into a plume of dust as soon as higher-res imagery comes down.

Posted by: ElkGroveDan May 16 2015, 01:29 PM

QUOTE (Gladstoner @ May 15 2015, 01:38 PM) *
is it possible the darkish areas surrounding the bright spots could be plume deposits?:

That's the only explanation that I can think of based on the visible details at this resolution.

What is the direction of Ceres rotation in these images?

Posted by: jgoldader May 16 2015, 02:32 PM

QUOTE (ElkGroveDan @ May 16 2015, 09:29 AM) *
That's the only explanation that I can think of based on the visible details at this resolution.

What is the direction of Ceres rotation in these images?


Triton's plumes are associated with the polar caps. There is a physical model for sublimation beneath the surface of the ice, and explosive release of gas pressure that brings up dust and such with it. There were a few active plumes and many streaks from past activity, so the geysers are a widespread phenomenon.

But the lack of polar caps or obvious surface ice deposits on Ceres would suggest (possibly require) a different mechanism. Any similarity in appearance may be coincidental. And I'm still really bothered by the contrast with essentially the entire rest of the surface, which appears rocky, with deep craters not obviously revealing high-albedo features indicative of ice deposits or ice layers. I don't recall seeing prominent "mud splats" like we see on Mars from areas where material appears to have flowed out of craters. Yet in this one place, a starkly different thing is found. The features in this crater appear to be quite different at least in appearance and size than other "bright spots" found on Ceres. If anybody has the time to do a compare/contrast, quantifying the differences, that would be very interesting. But I have grades due Monday...

Posted by: scalbers May 16 2015, 03:36 PM

Just a quick clarification that Triton's plumes & deposits are often found at low latitudes on this http://laps.noaa.gov/albers/sos/features/combined_triton_lon_zero_center.png, so I'm unsure why polar caps are being mentioned. Namazu Macula shown by Gladstoner is near the equator. Is the polar cap large enough to cover the entire southern hemisphere? I had heard that solar heating could help power the geysers that would be present at lower latitudes, though if we are near the summer solstice signficant solar heating would be present at all southern latitudes.

Posted by: Gladstoner May 16 2015, 04:43 PM

QUOTE (ElkGroveDan @ May 16 2015, 07:29 AM) *
What is the direction of Ceres rotation in these images?


Left to right.

Posted by: jgoldader May 16 2015, 07:49 PM

QUOTE (scalbers @ May 16 2015, 11:36 AM) *
Just a quick clarification that Triton's plumes & deposits are often found at low latitudes on this http://laps.noaa.gov/albers/sos/features/combined_triton_lon_zero_center.png, so I'm unsure why polar caps are being mentioned. Namazu Macula shown by Gladstoner is near the equator. Is the polar cap large enough to cover the entire southern hemisphere? I had heard that solar heating could help power the geysers that would be present at lower latitudes, though if we are near the summer solstice signficant solar heating would be present at all southern latitudes.


I believe the area you quoted is within the polar cap, which is very widespread. Contrast that terrain with the bluer terrain above it.

Posted by: Habukaz May 16 2015, 08:39 PM

It might be interesting to note that although Ceres has no visible (obvious, anyway) atmosphere in the images returned thus far, that does not necessarily mean that it does not have an atmosphere in a meaningful sense of the word.

Recently, there was published a paper about what the scientists thought http://www.planetary.org/blogs/emily-lakdawalla/2015/04081101-a-moon-with-atmosphere.html, a world that in images does not look at all like it has an atmosphere. If I understood it correctly, the presence of this atmosphere would mean that Callisto possibly could have some sort of winds. Now, we already have a detection water vapour around Ceres, meaning that the suggestion Ceres could have an 'atmosphere' (in the sense of the word in the blog post I linked to) shouldn't be that far-fetched.

That said, I suspect there is a less exotic explanation for that darker area; a feature that I have been http://www.unmannedspaceflight.com/index.php?s=&showtopic=7981&view=findpost&p=220233 of http://www.unmannedspaceflight.com/index.php?s=&showtopic=7960&view=findpost&p=218500 quite http://www.unmannedspaceflight.com/index.php?showtopic=7960&st=270 now. wink.gif

In this context, too, it seems relevant to bring up the comparison with http://www.unmannedspaceflight.com/index.php?s=&showtopic=7960&view=findpost&p=218909:




Around this crater, of course, the apparent darker area is found around all of the crater rather than just some of it. Here's http://lroc.sese.asu.edu/posts/148 with the asymmetry property (even complete with some bright stuff!):


Posted by: walfy May 19 2015, 08:52 AM

Another take on the latest Ceres series, in 3D:


Full-res here, and slowed down a bit: https://farm9.staticflickr.com/8798/17823924746_44fb7dd598_o.gif

And a full-res of the dwarf planet spinning little faster: https://farm9.staticflickr.com/8761/17663309318_990077a52f_o.gif

Not sure why lighting shifts in some frames, thought I did each stepp the same. it pops out of the screen, which is how it renders when putting it together the quickest. It might be cool to have it recessed, as if peering from a spaceship window, but would take a bit more time. Such a lonely, mysterious, pretty little world! That volcano-like structure is as strange as the white spots. Enjoy these days of discovery!

Posted by: jgoldader May 19 2015, 11:03 AM

QUOTE (Habukaz @ May 16 2015, 04:39 PM) *
In this context, too, it seems relevant to bring up the comparison with http://www.unmannedspaceflight.com/index.php?s=&showtopic=7960&view=findpost&p=218909:




Around this crater, of course, the apparent darker area is found around all of the crater rather than just some of it. Here's http://lroc.sese.asu.edu/posts/148 with the asymmetry property (even complete with some bright stuff!):


The first image is of a crater named Sander, which has bright "hollows." From looking at the movie of bright spot 5 posted a couple of pages ago, it sure looks to me that the white patches in spot 5 are in hollows. Time will tell. In digging around, I found an interesting article discussing the discovery of the bright hollows on Mercury, including those in Sander. It contains a very high-res image of Sander as well.

http://messenger.jhuapl.edu/the_mission/publications/Blewett.2013.pdf

The features in Sander may be from some sort of sublimation-related process, at least that was the speculation at the time of the article. The visual similarity between Sander and bright spot 5 is pretty striking, at fairly low resolution. I wonder if we'll ever get a shot like the high-res image of Sander in that post. But thanks for posting the Sander image, it was enough to remind me to be skeptical about whether ice has any role in spot 5. What a vexing feature!

Posted by: John Broughton May 19 2015, 02:38 PM

The largely resurfaced region south of the crater with the bright spots is devoid of medium to large craters, but curiously is peppered with more small craters than older terrain.


Suppose mud flows carrying giant icebergs covered this area; shouldn't frozen mud quickly develop its own insulating layer of dust, but pits will be created as the relatively pure icebergs sublimate away? Maybe the outer 10km or so of the crust is made of frozen mud, with pure ice further down. That would explain why there's no evidence of ice having been exposed in larger craters and causing erosion there.

Posted by: alk3997 May 19 2015, 03:40 PM

QUOTE (John Broughton @ May 19 2015, 09:38 AM) *
The largely resurfaced region south of the crater with the bright spots is devoid of medium to large craters, but curiously is peppered with more small craters than older terrain.
...


Are those small craters or are they remnants of internal gas vents?

It is interesting how many "pieces" the right side bright spot has turned into. I think we've already seen an image where the main bright spot is at least two separate clumps. These could be very small and reflective mounds of material if it is impact related or very small outgassing pockets if it is an active area. Impact remnant still works for me at this resolution and doesn't require internal heating.

Andy

Posted by: MarsInMyLifetime May 19 2015, 05:51 PM

Just to keep other causes in the discussion, we can't rule out some not-yet-obvious circumstance leading to secondary ejecta craters. But I do think the highly localized borders for some of these pits does speak to flows rather than ejecta. And other volatile materials than water could be at work as well. The Sander Crater example is similar only by possible mechanism; the soluble material there may have had a much higher temperature of sublimation/vaporization than water. In fact, I've seen solder blobs that pulled into such shapes; other volatile materials had nothing to do with the puddling behavior of the melted material.

Posted by: Habukaz May 20 2015, 04:20 PM

Yep, the bright spot is in http://photojournal.jpl.nasa.gov/catalog/PIA19559 navigation images (OpNav 8). Image quality is pretty poor, though.

Posted by: Gerald May 20 2015, 05:15 PM

For convenience, the bright spot 8-fold magnified, and brightness-stretched in a nonlinear way, darker parts mapped to black:


Posted by: elakdawalla May 20 2015, 05:25 PM

Personally I'm more than happy to accept lots of JPEG compression artifacts in exchange for relatively quick release of new images. So far Ceres has been so much better than Vesta in terms of image release.

Posted by: Steve G May 20 2015, 05:39 PM

We are finally at the point where we can't get all of Ceres in a single frame, so quality is amazing! It wasn't that long ago were were stretching to death 20 pixel wide images.

Posted by: Gladstoner May 20 2015, 05:40 PM

It's puzzling, though, that the associated TIF images have the same JPG artifacts. One would think they would use unaltered images for the ~1-meg files.

Posted by: JRehling May 20 2015, 05:55 PM

I thought I'd inject a comparison between Ceres' bright spots and albedo patterns that we've seen up-close on Phobos. Eg,
http://photojournal.jpl.nasa.gov/catalog/PIA10368

Phobos is of comparable distance from the Sun, and is also dark with bright spots. We can see that the bright areas underlie the dark surface and are exposed by combinations of impact cratering and downslope flow. We also see that craters within craters can create arbitrarily fine detail. We also see asymmetries that might not, a priori, be expected: Bright spots at certain places on a rim, but not in others, and bright patches where two causes of incline add (e.g., the upslope wall of a crater within Stickney), but no bright patches where two causes of incline cancel out (the other side of that crater within Stickney).

Overall, there is a simple layering of dark over light, and physical exposure of the ice happens for two simple reasons (impact and downslope mass movement), with anisotropies in topography causing boundaries that appear complex.

This seems like a prominent model to consider for Ceres' bright spots until better observations show the nuances of the bright spot boundaries.

Posted by: volcanopele May 20 2015, 06:30 PM

QUOTE (Gladstoner @ May 20 2015, 10:40 AM) *
It's puzzling, though, that the associated TIF images have the same JPG artifacts. One would think they would use unaltered images for the ~1-meg files.

It's possible that they were returned as lossy-compressed images. These were opnavs after all, needed more for navigation than for science, so fine surface details aren't as important as seeing where the limb is. I know with Cassini we have the option to use that or lossless compression. I always use lossless compression because Titan's atmosphere makes my data blurry enough...

Posted by: Gladstoner May 20 2015, 07:17 PM

QUOTE (volcanopele @ May 20 2015, 01:30 PM) *
It's possible that they were returned as lossy-compressed images. These were opnavs after all, needed more for navigation than for science, so fine surface details aren't as important as seeing where the limb is. I know with Cassini we have the option to use that or lossless compression. I always use lossless compression because Titan's atmosphere makes my data blurry enough...


I thought that might be the case, but the images in the recent animated GIF appear to be unaltered, while images selected from the same sequence and released in TIF and JPG format are degraded. A comparison, from left to right, are GIF (movie frame), TIF, and JPG:



I'm grateful they released that movie in the original quality.

Posted by: elakdawalla May 20 2015, 07:30 PM

It's horrible but true that the TIF versions of images at Photojournal are sometimes made from JPEG originals. It was probably provided to JPL by the FC team as a JPEG. Now, JPL could have just grabbed a still frame from the animation and posted that instead, but on missions there are agreements about different organizations having to post the same images at the same time, so it's not something they would ordinarily do.

Posted by: Habukaz May 20 2015, 07:46 PM

QUOTE (volcanopele @ May 20 2015, 08:30 PM) *
It's possible that they were returned as lossy-compressed images. These were opnavs after all, needed more for navigation than for science, so fine surface details aren't as important as seeing where the limb is. I know with Cassini we have the option to use that or lossless compression. I always use lossless compression because Titan's atmosphere makes my data blurry enough...


I asked about that, and it seems that the answer is no:

QUOTE
Most of the compression artifacts you are seeing are the result of the conversion from raw data to JPEG format


https://twitter.com/NASA_Dawn/status/601070407094009856

Posted by: charborob May 20 2015, 07:53 PM

While converting to JPEG, why didn't they specify "maximum quality"?

Posted by: scalbers May 20 2015, 07:56 PM

A simple map with a bright spot image projected onto the previously released map.


Posted by: Gladstoner May 20 2015, 09:28 PM

This crater floor fracture shows a little more detail in the new release:


Posted by: ngunn May 20 2015, 09:42 PM

QUOTE (JRehling @ May 20 2015, 06:55 PM) *
I thought I'd inject a comparison between Ceres' bright spots and albedo patterns that we've seen up-close on Phobos


Excellent analysis (as ususal) but I'd be surprised if the bright material on the surface of Phobos was ice, so is it salt? If so that gets us somewhere.

Posted by: JRehling May 21 2015, 01:56 AM

QUOTE (ngunn @ May 20 2015, 02:42 PM) *
Excellent analysis (as ususal) but I'd be surprised if the bright material on the surface of Phobos was ice, so is it salt? If so that gets us somewhere.


Thank you, ngunn.

Indeed, Phobos shows no signs of H2O, and the various colors on Phobos are interpreted as different kinds of rock, with the details unknown, but which kinds of rock may not matter so much for this discussion. (The brighter rock is considered as possibly mafic.)

http://onlinelibrary.wiley.com/doi/10.1029/90JB02354/abstract

Of course, ice can participate in different dynamics that rock cannot, but if this is simply a matter of impacts and mass movement, that may not matter.

Other worlds where we've seen the results of downslope movement of fine material on crater slopes include Eros and possibly Hyperion, but those patches on Phobos seem to look the most like Ceres'... for now.

Posted by: ngunn May 21 2015, 10:07 AM

I was mulling over the question of how compact clusters of impact craters could form in the absence of an atmosphere to cause disintegration of the incoming object. I found this source helpful:

Having trouble posting the link but it's abstract 1759 from LPSC44, 2013
http://www.google.co.uk/url?sa=t&rct=j&q=unusual%20dense%20clusters%20of%20impact%20craters&source=web&cd=1&cad=rja&uact=8&ved=0CCcQFjAA&url=http%3A%2F%2Fwww.lpi.usra.edu%2Fmeetings%2Flpsc2013%2Fpdf%2F1759.pdf&ei=mrNdVf2YFvPe7AbsvYM4&usg=AFQjCNEZ-S48WedJ6c_IOML42lYxRJ18Eg&bvm=bv.93756505,d.ZGU
Ah that one seems to work . .

Posted by: Gerald May 21 2015, 11:32 AM

Yes, thanks, that's a plausible approach! Once a loosely bound "http://en.wikipedia.org/wiki/Rubble_pile" approaches a celestial body closer than the http://en.wikipedia.org/wiki/Roche_limit, it will disintegrate.
Then it's straightforward, that the impact will expose fresh / bright subsurface material.

Posted by: Ken2 May 21 2015, 05:26 PM

It is a interesting article and hypothesis - however it did seem to prefer a 2 body system ( earth moon ) to break up an asteroid - though a single impact's delayed secondaries was also mentioned which would probably be the best for Ceres

I would think the main multi-body impact swarm mechanisms for Ceres would be

1) Direct secondaries from large impacts,
2) Medium/long duration secondaries from large impacts orbiting debris (BTW where are all the little moons that could be formed from this? - Cere's orbit must not be stable very long (relatively speaking))
3) Does Ceres have enough gravity to break up a rubble pile into a chain / cluster before impact? - if so then maybe just a Ceres impact of a very loosely bound body. (see previous post!)
4) Jovian / Martian perturbed comet/asteroids that get lucky and impact Ceres as chains.
5) Maybe a close approach to Ceres causing breakup and a lucky return later - but I would think the dispersal would be too much by the return date.

I don't think any of these look good for the spot 5 cluster, other than 1),3) - 1) an impact and direct secondaries. (maybe an impact into a preexisting central peak and it oblong blasted part of the peak out and caused shrapnel at the local peaks of the second spot cluster terrain. (loose analogy - mt saint helens sideways explosion)
2) Medium/long duration secondaries - would probably hit a crater rim (though if spot 's host crater initially had a central peak - maybe it could hit it first),
3) would likely be most of a long chain (visible elsewhere on Ceres.) - though maybe Ceres' gravity could break it up as a cluster shortly before impact.
4,5) I doubt the chain would be so localized for a distant breakup - probably just a few separate craters.

Posted by: ngunn May 21 2015, 06:20 PM

QUOTE (Ken2 @ May 21 2015, 06:26 PM) *
3) Does Ceres have enough gravity to break up a rubble pile into a chain / cluster before impact?


I was looking for an answer to that very question. A bit of googling comes up with a Roche limit for a rubble pile approaching Ceres at a distance of approximately 1500 km. so I'd offer a tentative "Yes"' (though I'd like to hear from someone more knowledgeable on that point). The resulting crater cluster would not necessarily be much elongated if the impact was near vertical.

Posted by: Gerald May 21 2015, 07:21 PM

It depends on the density, shape, and rigidity of the rubble pile. The upper density limit for a non-rotating spherical rigid rubble pile would be twice the density of Ceres to disintegrate. In this limiting case the rubble pile would disintegrate just at Ceres' surface.
In the fluid case the limiting density would be about the 14.5-fold of Ceres' density, beyond any reasonable assumption, i.e. any reasonable rubble pile of the fluid type would disintegrate.
The truth for just gravitationally bound non-rotating rubble piles should be somewhere between these two extreme models.
For a non-rotating liquid-model rubble pile the density of Ceres, disintegration would be near 476 km x 2.44 = 1161 km above center, or 1161 km - 476 km = 685 km above the surface.
Disintegration near 1500 km from Ceres' center would apply e.g. to the liquid model of density (476 /1500)³ x 14.5 = 0.032 x 14.5 = 0.464 the density of Ceres, or about 0.032 x 14.5 x 2.1 g/cm³ = 14.5 x 0.067 g/cm³ = 0.97 g/cm³.
(Edit: added the missing factor 14.5 for the liquid model in the previous sentence)

Note:
- 1.26³ = 2, in the formula of http://en.wikipedia.org/wiki/Roche_limit#Rigid-satellite_calculation,
- 2.44³ = 14.5, in the simplified formula of http://en.wikipedia.org/wiki/Roche_limit#Fluid_satellites.

Posted by: Blue Sky May 21 2015, 07:38 PM

I would think a rubble pile approaching on a glancing blow could get broken up.
Comet Shoemaker-Levy was disrupted on a close pass by Jupiter years before
it impacted.

Posted by: ngunn May 21 2015, 07:47 PM

Well I used a density ratio of 3 in the formula for the liquid case to get 2.455x450x1.44(cube root of 3) = 1590 km.

Posted by: Gladstoner May 21 2015, 10:34 PM

There appears to be a dark linear feature extending between the bright areas:



Contrast enhanced and marked:



This could be a valley, a northward-facing slope, or an albedo feature. It persists in most images, but seems to disappear when near the limb, probably due to the unfavorable angles (edit: it may still be visible in the right image):



For comparison, a narrow valley on the floor of a nearby crater:


Posted by: elakdawalla May 22 2015, 12:28 AM

Hmm, I think you may be on to something, Gladstoner. It's right at the limit of resolution.

I just asked someone on the Dawn team whether the JPEG artifacts in the Ops Nav 8 happened before transmission to Earth or after, and she said after. So we have better quality to look forward to upon PDS release.

As part of a blog entry I'm working on, I mapped all the schmutz on the detector; I find 8 or 9 spots that show up after stacking all the animation frames (I'm not completely sure that the upper rightmost one is schmutz; there are fewer frames in that area). It is very difficult to find these artifacts in the Ops Nav 8, but eventually I found them; they are almost completely eradicated by JPEG artifacts. Which isn't necessarily a bad thing!

http://planetary.s3.amazonaws.com/assets/images/9-small-bodies/2015/20150521_ceres_dawn_fc_shmutz.png

Posted by: Bjorn Jonsson May 22 2015, 12:42 AM

QUOTE (elakdawalla @ May 22 2015, 12:28 AM) *
...As part of a blog entry I'm working on, I mapped all the schmutz on the detector; I find 8 or 9 spots that show up after stacking all the animation frames


To speed things up, when processing the PDS Vesta images I made a Photoshop file containing a selection which includes just the schmutz that I had to remove semi-manually. IIRC I had six of these in that file but discovered that there were a few more that are more subtle and that I will be adding to the Photoshop selection in the future.

But now there is this: http://www.jpl.nasa.gov/news/news.php?feature=4594

I'm not exactly happy if I turn out to be right but the Dawn team now seems to think the bright stuff might be ice as I have been suspecting (comparisons to Callisto played a role there in my case). Something else causing the bright spots would have been more exciting.


Posted by: Gerald May 22 2015, 01:00 AM

QUOTE (Gladstoner @ May 22 2015, 12:34 AM) *
There appears to be a dark linear feature extending between the bright areas...

This could be a valley, a northward-facing slope, or an albedo feature.

Since there seems to be no parallel brighter line in any of the images, a valley seems to be the least likely option.
A northward-facing slope would be more consistent. So it could be the southern border of a depression.

---

Regarding the bright material: I would be really surprised, if it would actually turn out to be water ice. My favorite at the moment is some kind of reworked evaporite, with most of its humidity already sublimated.

Posted by: fredk May 22 2015, 01:34 AM

QUOTE (Bjorn Jonsson @ May 22 2015, 01:42 AM) *
the Dawn team now seems to think the bright stuff might be ice

That release only says "possibly ice" and doesn't elaborate. Perhaps you're referring to other released statements?

Posted by: Gladstoner May 22 2015, 02:32 AM

QUOTE (Bjorn Jonsson @ May 21 2015, 07:42 PM) *
I'm not exactly happy if I turn out to be right but the Dawn team now seems to think the bright stuff might be ice as I have been suspecting (comparisons to Callisto played a role there in my case). Something else causing the bright spots would have been more exciting.


It would be relatively 'ho-hum' if the bright areas had a Callisto-like distribution across Ceres, but these are so.... isolated. This could indicate:

1. There are scattered formations of the bright stuff below the surface that occasionally get exposed by impacts or landslides. These could be vein swarms, dikes, diapirs, or otherwise some kind of filled conduits or intrusive structures.

2. The bright stuff is more extensive beneath the surface, but it rapidly fades after being exposed by impacts or landslides. Such events would have to have happened in the (relatively) *very* recent past.

3. Some combination of 1 and 2. Edit: In either case, the original formations/structures could have been disrupted by subsequent impacts, and some of the smaller spots could be from large megabreccia clasts.

4. The bright stuff was deposited on the surface. This could be erupted flows of ice, salt deposits left after sublimation of brine, or who knows. Such deposits could fade over time as well.

(5. Other processes that I can't think of at the moment.)

To me, the fact that the bright area is so isolated, but yet is made up of smaller, scattered spots of varying sizes, seems to indicate that something quite interesting is going on here. 'Mundane' impacts or landslides exposing extensive but rapidly fading material -- the most 'boring' possibility -- seem to be less likely (unless the impact or slide was complex, e.g. disrupted rubble-pile meteoroid, as mentioned in posts above).

A question that will be answered soon: Are the bright spots on a surface that is smooth & flat, rough, or a combination? That should narrow down the possibilites once the slightly higher-res images come in. A (possible) fracture/valley in the midst of the spots could be dramatic indeed.

Posted by: John Broughton May 22 2015, 06:56 AM

"There appears to be a dark linear feature extending between the bright areas"

It's part of the regional system of parallel grooves. This particular one extends well outside the crater rim on both sides and joins up with the most prominent groove about two crater diameters to the ESE. Some minor spots in the crater are not aligned, so I expect we'll see more cracks show up there as the resolution improves.

Posted by: Gladstoner May 22 2015, 08:16 AM

QUOTE (John Broughton @ May 22 2015, 12:56 AM) *
"There appears to be a dark linear feature extending between the bright areas"

It's part of the regional system of parallel grooves. This particular one extends well outside the crater rim on both sides and joins up with the most prominent groove about two crater diameters to the ESE. Some minor spots in the crater are not aligned, so I expect we'll see more cracks show up there as the resolution improves.


Hmmm.... If these turn out to be fractures that run deep, they could potentially serve as conduits for ascending fluids.

Posted by: John Broughton May 22 2015, 08:53 AM

QUOTE (Gladstoner @ May 22 2015, 08:16 AM) *
Hmmm.... If these turn out to be fractures that run deep, they could potentially serve as conduits for ascending fluids.

Here's the general course of that fault.

Like the large mountain spot and another spot of small cones near that, the bright spots coincide exactly with fractures in the crust. The great length of some of these faults is a definite sign they run deep.

Posted by: TheAnt May 22 2015, 11:27 AM

The idea of ascending fluids is a good one, but still have to rise a very long distance against gravity.
If it on the other hand is water vapour, created by water boiling against the close-to-vacuum in a deep crack.
Then vapour pressure would give it an extra boost enough to reach the surface.
This could deposit salts and ice, either or both at the exit, so it does not solve the problem of what the bright material is composed of.
But do at least make transportation to the surface more likely.

Posted by: Habukaz May 22 2015, 05:06 PM

The http://photojournal.jpl.nasa.gov/catalog/PIA19561 released OpNav 8 image appears to have a much better quality, although it does not show the brightest spots (grr).

If we got more of the feature below (it should be a crater) over the weekend, that would be interesting. It might hold some important clues to all bright spots, including the brightest.


Posted by: scalbers May 22 2015, 05:40 PM

Here's a revised Ceres map, using 4 more recent images on top of the previous official map. Resolution now up to 4K.



I'll see about adding the OpNav posted just above.

Posted by: Ken2 May 22 2015, 06:56 PM

The two Spot5 Opnav8 images to date - with all the unfortunate jpeg compression artifacts.

The top half of the image has the more recent (5/21/2015) halfway to the limb image stretched and rotated to compare exactly with the first one (5/20/2015). As you can see it shows a bunch more small craters to the left of the big spot. A complex crater morphology such as this can produce any number of weird patterns. If it's an impact - I think it is going to take HAMO or LAMO picts to determine if it was one parent body and shrapnel/secondaries or a close rubble pile breakup. Given the direction of the dark right sided rays, I still vote for a single impact with a few direct secondaries.


Posted by: scalbers May 22 2015, 06:58 PM

And here is the map with today's OpNav added.




Posted by: Ken2 May 22 2015, 08:46 PM

QUOTE (scalbers @ May 22 2015, 11:58 AM) *
And here is the map with today's OpNav added.


Thanks - I like the maps scalbers - keep 'em coming!

I have one item on my wish list - would it be possible add a second map with north and south polar projections? - the poles get so distorted in Mercator projections.

Posted by: antipode May 22 2015, 10:07 PM

Hmm, hard to tell with that projection, but is the small white patch upper right (not sure if its one of the officially numbered patches) 'downrange' from the twin splotches?



I know, probably trying to find patterns where none exist! I like the fracture[s] idea actually, that would be more interesting than just a low angle impact.

P

Posted by: Gladstoner May 22 2015, 10:40 PM

A can of Diet Coke today had me thinking. We all have accidentally left a can of soda in the freezer. Long after a half hour (when it should be cold enough to drink, i.e. should have been taken out of the freezer), carbon dioxide begins to come out of solution as the water freezes. Eventually the can ruptures as the gas pressure becomes too great, and a very-syrup-rich slurry sprays into the freezer interior to make a fine mess.

Now back to Ceres. Assuming the body differentiated into a rocky core and icy mantle, could a similar process have happened within Ceres? Ice would first form near the surface and progressively freeze downward. Various volatiles (like the CO2 in the can) and cations & anions/dissolved salts (the syrup) would become more and more concentrated in the remaining brine. Over the age of the solar system, the water probably would have frozen out long ago, but there could still be remaining pockets of gas and possibly highly-concentrated brine. These would be *roughly* analogous to petroleum reservoirs on Earth in the way they permeate the substrates. Now, Ceres wouldn't rupture like a pop can, but some of the volatiles may eventually make their way to the surface (thanks to some minor tectonic adjustments due to an impact, perhaps?). The conduit at or near the surface would be marked with bright salt deposits. The extra brightness of the material could be due in part to micrometeoritic impacts on exposed transparent or translucent salts, kind of like the frosting that occurs when a similar material is sandblasted.

Of course this could be completely wrong, but it seems to make the most sense to me.

Posted by: scalbers May 22 2015, 11:08 PM

Good idea Ken2 - I put together a quick procedure to make a polar image. Shapes are a bit distorted near the edge as I've yet to add the niceties of a stereographic projection - this should give an idea of things though. North pole is in the center and zero longitude should be on the top. The south pole is devoid of data on this map so I'm holding off on it for now.



That small white spot on the right pointed out by antipode (2 posts up) indeed looks interesting. It might be close to being on a great circle from the two brightest spots from what I can tell. Looking at the cylindrical map (5 posts up) in Celestia might help, though it should be pointed out the cylindrical map is in planetocentric coordinates and Celestia usually expects planetographic. I'm accounting for Ceres being an oblate spheroid in this manner.

Posted by: John Broughton May 22 2015, 11:56 PM

There are at least three possible volcanic cones associated with this spot. I've inverted the image so it is illuminated from above.


The spot lies on a fault line running from the top left to the bottom right corner, but is indistinct at this high sun angle. As far as I can tell, hills are at the centre of all spots, whether they lie within craters or not.

Posted by: PDP8E May 23 2015, 03:12 AM

My deconvolve program had a little fun with this JPGy file... but not the best of results (arrggg!)
I turned down the background to try to focus on the lighter stuff... its about 5x


Its obviously an abandoned asteroid mining operation ... nothing to see here .... move along people... smile.gif
We shall have to wait for more RCx to HAMO to LAMO to WHAMO!





Posted by: Gladstoner May 23 2015, 05:22 AM

QUOTE (PDP8E @ May 22 2015, 10:12 PM) *
Its obviously an abandoned asteroid mining operation ...


Anyone can see it's an Illudium Q-36 Explosive Space Modulator.

Posted by: SFJCody May 23 2015, 06:34 AM

I just think the whole of Ceres is like Vastitas Borealis on Mars. Regolith over a widespread layer of almost pure water ice. As with Mars, the most recent impacts reveal this ice. Over longer timescales the exposed ice sublimes away and eventually escapes Ceres.

Posted by: Bill Harris May 23 2015, 10:17 AM

QUOTE
put together a quick procedure to make a polar image.


Is that a large degraded crater near the North pole or is it an "occipital" illusion?

--Bill

Posted by: Habukaz May 23 2015, 12:59 PM

Yesterday, Dawn took its last navigation images of Ceres before it reaches the survey orbit, which should be on the day 2 weeks from now.

http://dawn.jpl.nasa.gov/mission/status.html

Posted by: scalbers May 23 2015, 04:13 PM

QUOTE (Bill Harris @ May 23 2015, 10:17 AM) *
Is that a large degraded crater near the North pole or is it an "occipital" illusion?l

Could be fortuitous arcs of craters and/or brightness changes due to processing artifacts. However as I consider ways to smooth things better in the map I see some possible albedo variations that may be intrinsic as in this small section of an original image (PIA 19545):



Or maybe it's simply larger scale gentle relief causing some shading as seen in this context view:


Posted by: Gladstoner May 23 2015, 04:53 PM

Smooth mountains and large valley.... Are they related, or aligned by mere coincidence?






Posted by: TheAnt May 23 2015, 07:43 PM

QUOTE (Gladstoner @ May 23 2015, 12:40 AM) *
.................The conduit at or near the surface would be marked with bright salt deposits. The extra brightness of the material could be due in part to micrometeoritic impacts on exposed transparent or translucent salts, kind of like the frosting that occurs when a similar material is sandblasted.


I like that idea, it's a plausible idea that could have created this feature. So it get added to my list of possible scenarios.
Good work on that valley feature btw. =)

So as for the impact hypothesis, well its further down on my list. The twin dots at right do look a bit like impacts, but the largest one does not. And it's the only one large enough to show any actual structure. The deconvoluted image by PDP8E make me even more stubborn on that matter. =)


Posted by: Gladstoner May 23 2015, 07:53 PM

QUOTE (ZLD @ May 12 2015, 09:57 AM) *
Heres another way of viewing the mound in RC3. Centered and rotated the frames to reproject a flyover of the area. The mound appears to be sitting on either highlands or an uplift of some sort. Interesting!


Could you do a similar treatment with this bright feature?:



It looks like a crater, but the distribution of the white stuff is hard to make out.

Posted by: scalbers May 23 2015, 08:43 PM

On the left is a slightly different perspective on that white spot (with image dropout or something - PIA 19543). Lower sun view is on the right.



Here's one of the other white spots we see now from a different perspective than earlier.


Posted by: Gladstoner May 23 2015, 10:29 PM

Thanks. In the latest image, it looks more like a notch in a ridge.

Posted by: scalbers May 23 2015, 11:57 PM

I'll eventually do this at high resolution, though it's hard to resist posting these versions that now have more complete coverage. Cylindrical and South Polar.




Posted by: ngunn May 24 2015, 07:29 AM

I'm curious as to why the 'sand dollar' crater seems half obliterated in your maps. In the rotation movie it's quite prominent over a big range of illumination angles.

Posted by: scalbers May 24 2015, 04:05 PM

Good question. In the lower res rotation movie apparently used in the official map this shows up better since Dawn's viewpoint is closer to the 'sand dollar' latitude. In my map the lower half of this is shown from the low res data and the upper half from the higher res data where this is closer to the southern limb from Dawn's viewpoint. Thus the interior part of the northern basin rim is somewhat hidden from view and has less shadowing. I have since adjusted the cutoff latitude between these two image components, though only enough to get about 60 cents of the 'sand dollar' to show with more contrast. Maybe I can locally adjust this cutoff latitude. It's a tradeoff of image feature contrast vs resolution.

I also wasn't initially using imagery that is very close to the longitude of the 'sand dollar', so I have added a higher resolution image (from the second movie) to fill that longitude gap so it shows up better.

http://laps.noaa.gov/albers/sos/asteroids/ceres_rgb_cyl.png

Click on image for full 4K resolution cylindrical map. There's even a white spot on the NW rim of the 'sand dollar'. Here are http://laps.noaa.gov/albers/sos/asteroids/ceres_rgb_npolar.png and http://laps.noaa.gov/albers/sos/asteroids/ceres_rgb_spolar.png projections.

EDIT: All three versions updated 1610UTC May 26.

Posted by: John Broughton May 25 2015, 01:12 AM

One of the albedo spots visible in OpNav3 images that I've been interested in seeing up close, is the central mountain complex of this deep southern basin.


Lo and behold this feature appears to be located at the intersection of several long fracture lines. Of course, central hills are a frequent consequence of impact, but on Ceres they tend to be the same low albedo as crater floors and everything else, unless (in my opinion) such sites have been active after formation of the crater and fault lines.

Posted by: ZLD May 25 2015, 05:59 AM

QUOTE (Gladstoner @ May 23 2015, 02:53 PM) *
Could you do a similar treatment with this bright feature?:

It looks like a crater, but the distribution of the white stuff is hard to make out.


This appears to be stranger than it first appeared to me. It almost seems to be a conical depression rather than a crater. Then, the bright areas appear to maybe even be flows from this depression. Maybe this is a ground level geyser?



Lancoz resampling:
http://i.imgur.com/7gTcn1j.gif
(click to animate)

Posted by: Gladstoner May 25 2015, 07:58 AM

QUOTE (ZLD @ May 25 2015, 12:59 AM) *
This appears to be stranger than it first appeared to me. It almost seems to be a conical depression rather than a crater. Then, the bright areas appear to maybe even be flows from this depression. Maybe this is a ground level geyser?

Lancoz resampling:

(click to animate)


Thank you!

There is at least some interplay of the bright stuff and shadows that doesn't seem to 'fit neatly' into a 'conventional' crater wall and floor. Can't wait for a closer look.

Posted by: jgoldader May 25 2015, 12:18 PM

Not meaning to degrade the S/N, but as a recovering professional astronomer, I thought I knew image processing back in the day, but the work I'm seeing here just blows me away. Kudos and great thanks to all the folks- pros and those in it for fun- who are creating the absolutely incredible visualizations and animations we've been treated to in this thread. You've got software and hardware I couldn't have even dreamed of, and you aren't afraid to use them. Thank you again!

Now, about that bloody spot 5...

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