[X] My Assistant

[aldo12xu]

I think Ultreya is for real; that is, it's a depression of some sort. The stereo images I've posted on my site view Ultreya from four different perspectives and in my mind, I see a collapse feature from all angles. I was also able to do a bit of geological interp and the units I delineated bear that out as well.

http://www.marsgeo.com/Spirit/Ultreya.htm

There's a link to view the stereo pairs in crosseyed as well, if the parallel method doesn't work for you. I'll try to post an updated anaglyph with the geological interp and also one of the entire Columbia Hills.

Further evidence that it's a true depression comes from this MOLA image. Ultreya is extremely dark (ie extremely low) relative to the other topographic features of the area.

http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20041207a/sol324_travDEM-A332R1.jpg[url="http://http://marsrovers.jpl.nasa.gov/gallery/pre...vDEM-A332R1.jpg://http://marsrovers.jpl.nasa.gov/gall...-A332R1.jpg" target="_blank">
http://marsrovers.jpl.nasa.gov/gallery/pre...vDEM-A332R1.jpg


Cheers,
Aldo.

[url="http://www.marsgeo.com/"]http://www.marsgeo.com/://http://marsrovers.jpl.nasa.gov/gall...ww.marsgeo.com/

[Pando]

Well, here's one evidence that suggests that it's simply an imaging anomaly. In the image below (edited from an image on your site), the dark feature also exists in the canyon east of Tennessee Valley, where Spirit is now headed. Note the difference between the two sides. The dark feature almost disappears on the right side, leading me to believe that light is playing tricks on you - the grayscale is simply saturated at low end and it's not a 'bottomless pit.'

[centsworth_II]

Our Earthly experience trains us to expect to see things even if they are in shadow.
If we see nothing in a shadow, we assume there is a hole. This may be a good assumption on Earth,
but may be a mistaken assumption on Mars.

That's the problem with a thin atmosphere that scatters sunlight weakly. On Earth the thick atmosphere
scatters sunlight so that even areas not directly in sunlight recieve scattered light. The result is "transparent shadows" in which detail can be seen.
On Mars, the lack of such light scattering results in dark, opaque, shadows that cannot be seen into.

[aldo12xu]

When I look at the dark area you circled in stereo, it doesn't have any depth to it. I see a cliff face with a shadow. But when I look a Ultreya in stereo it has depth to it. Have you viewed the images in stereo? Notice the pink coloured blocks in my interp that seem to be in different levels of falling into the hole.

We'll just have to wait & see for what view Spirit will give us........time will tell

[Pando]

I was merely pointing out the similarities in the dark areas. When I look at the dark feature ("Ultreya") in stereo all I see is, well, a 'dark' area no detail there that I can see. That doesn't mean that it's a hole. It simply means that the imaging system couldn't resolve the dark feature; the image is clipped at the low end of the grayscale, just as it did portions of the Bonneville crater and we know what it looks like.

Same can be said with the circled left image above - it's just as dark as the 'Ultreya' area. 3-d viewing is not as effective since the right side is different - detail can be seen there that destroys the 3-d .

So in effect yes, we'll have to wait either for Spirit to take a look, or some better MGS images that I'm sure they have taken but have yet to be released.

[slinted]

I went back to the original IMG images from MOC. The 0 brightness nature of the 'abyss' only comes from a stretching of the brightness values done on the jpg/gif releases of these images.

These are brightness stretched from the raw images to retain a bit of the detail inside the abyss.

E03-00012:



R02-00357:

Both images are taken with very low sun angles (40 degrees above horizon for E03-00012 and 39 degrees above horizon for R02-00357) which might help explain the shadowed effect.

Note the dark band running across the 'abyss' in the R02-00357 image. R02-00357 was taken 2 years after the first, and shows many dust devil tracks (click the above images to see the larger frames). I wonder if this dark band cutting across the 'abyss' is itself a dust devil track across the dark material in the basin.

[Nix]

Yes There does appear to be some data in the dark area but to me it appears to be dark soil and / or shadow. I'm tempted to see something else but, ..I don't know, we'll just really really have to wait.

[tedstryk]

It would be neat to go down there, but right now I just want to get to the top of Husband hill. It would be really cool to park there for a while, take a complete pan in all colors, and send back multiple low compression images of each area in at least one color for super resolution imagery. That would produce one hell of a pan.

Ted

[jdub]

Someone asked if there is an anaglyph of the Columbia Hills and the "Ultreya Abyss". This is the only one as far as I know:

http://www.marsunearthed.com/Specials/Colu...ltreyaAbyss.GIF

Here's a side by side comparison of some MOC images of the area.

http://www.marsunearthed.com/Specials/Colu...aHillsComp3.JPG

These dark patches, which are spread all over this area, look to me like pockets of dark fine material. It's not clear if this material is local or is blown in from somewhere else. My theory (probably not original) is that there are places where the surface comes into contact with subsurface layers or pockets of dark, fine material which is probably volcanic in origin. This same thing can be seen in other MOC images from other regions.

[CosmicRocker]

That was a nice anaglyph of the hills, but the dark end is still saturated. This is no mystery. There is no humongous sinkhole. The unsaturated images show normal topography in the supposed 'abyss.' As far as I can tell, Ultreya Abyss is history.

I'm going to bed, and that's where this topic should be put.

[CosmicRocker]

I didn't intend to ignore your last paragraph...Right, it is either dark stuff brought in from elsewhere, or dark stuff that has been unearthed, maybe with some help from the shadows.

[ustrax]

Long live Ultreya!

http://img.photobucket.com/albums/v352/ustrax/ultreyans.jpg

[atomoid]

While were waiting for direct imaging of "Ultreya" to be made hopefully sometime in early 2006, heres a peek at what it might turn out to look like, given that the dark (in some wavelengths) patch on the side of the hill imaged in Spirit images from sol 582...

...would appear to correlate to the same 'dark' area near the top of the mgs images below.
So, just a bunch of 'dark' soils? (even so, that 'dark' soil... whats it? why in these patches? doesnt seem associated with any conspicuous outcrop...)

[ustrax]

We're at the border and it's...dark...

http://i16.photobucket.com/albums/b14/ustr...treyaborder.jpg

How...darker can it get?

[prometheus]

There is detail in the dark. A little ImageJ magic reveals:



The two images are not for xeyed 3d but just to compare ground features