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FieryIce
2004-Jun-06, 04:58 PM
Mars observed in 1976 by the Viking Orbiter then observed again by Mars Odyssey mapping (2001-04).

http://www.craterchains.com/ns/mars1tan2.jpg
Viking Orbiter Image (http://daac.gsfc.nasa.gov/DAAC_DOCS/geomorphology/GEO_10/geo_images_P-7/PlateP-7.jpeg) Themis, Thermal Emission Imaging System (http://themis.asu.edu/mars-bin/mars_cgi_map.pl?TOP_LAT=64.8491885&LEFT_LON=143.01 793383&CENT_LAT=19.8491885&CENT_LON=233.01793383&D ISP_RES=4&DISP_DATASET=Visible&DISP_MAP_DATASET=1& DISP_MAP_PROJ=0&TNAIL_LINK=20040405a&PAN_SELECT_ZO OM=ZOOM&MAP_IMG.x=529&MAP_IMG.y=246)

Comparing these two images there are significant differences in the geology of Mars, 1976 compared to 2001-2004. Mariner 9 images from 1971 also show geological changes on Mars compared to the present Odyssey mapping images.
I found it amazing the changes in the geology of Mars when considering observed and photographed observations of Mars from the middle to late 1800’s.
Putting all these pieces together illustrates the historical changes on Mars to be within about the last 150 years. Astronomers Saw! (http://www.craterchains.com/ns/observationhistory.html)

Craterchains
As a boy I remember all the speculation about the canals on Mars. Reading about them in science magazines and the science fiction books was fascinating. As noted by many astronomers in their drawings, photos, and notes over the past couple hundred years there have been some major changes.
When FieryIce brought to my attention this APOD of Mars, Mars Then and Now (http://antwrp.gsfc.nasa.gov/apod/ap031112.html) and questioned about the canals I suggested she do some research and see what comes up. Her investigations have produced some interesting observations made by astronomers and we offer our combined effort for your comments and ideas about these easily observable changes to Mars.

:D

R.A.F.
2004-Jun-06, 05:48 PM
I found it amazing the changes in the geology of Mars...

Actually, you're assuming these "changes" took place. (I don't know why).

To my untrained eye these images "appear" different for one reason only and I can say it in 2 words...Image Resolution!

Chip
2004-Jun-06, 09:51 PM
Mars observed in 1976 by the Viking Orbiter then observed again by Mars Odyssey mapping (2001-04)...Comparing these two images there are significant differences in the geology of Mars, 1976 compared to 2001-2004.

I don't think so. The images themselves are different in quality, but the features look the same, especially from such high altitude.


Mariner 9 images from 1971 also show geological changes on Mars compared to the present Odyssey mapping images.

There can be coloration differences due to the effect of dust storms. The canyons and craters are in the same places.


I found it amazing the changes in the geology of Mars...I remember all the speculation about the canals on Mars...Reading about them in science magazines and the science fiction books ...noted by many astronomers...

"Many astronomers" are? You're probably thinking of Percival Lowell (http://www.physics.gmu.edu/classinfo/astr103/CourseNotes/ECText/Bios/lowell.htm).

craterchains
2004-Jun-07, 02:30 PM
Yes, the resolution between the different photographic systems on the various probes is noted, but doesn’t qualify as a discovery of change. With out assumptions of any kind and with out the need of a trained eye most people can see changes between photographs taken over time, if there are changes.

FieryIce and I are jointly conducting this investigative thread into possible Mars changes as shown in the photographs taken over the past few decades, and as stated in her first post. These are not the only before and after pictures available on the web and the others should be investigated along with what we posted here. As this thread develops we will be posting links to other pictures on the web for perusal. It is our hope that others will find photos that we haven’t listed that will add to this topic.

We have added the grid for orientation ease of discussion for changes discovered.

Laser Jock
2004-Jun-07, 02:45 PM
I found it amazing the changes in the geology of Mars...

Actually, you're assuming these "changes" took place. (I don't know why).

To my untrained eye these images "appear" different for one reason only and I can say it in 2 words...Image Resolution!

Image resolution is the biggest difference for sure. Also, some of the images in the Viking composite look like they were taken at a sharp angle rather than directly overhead. I think the difference in perspective would explain the "change" in position of the three large circular objects (craters?, volcanos?) on the left side of both images.

R.A.F.
2004-Jun-07, 03:15 PM
Also, some of the images in the Viking composite look like they were taken at a sharp angle rather than directly overhead.

Good call, Laser Jock! Now that I look closer, it's appearent that the Viking composite was taken at an angle, while the MOC image was taken from directly above.

I'm also wondering about the angle of the Sun when BOTH images were taken. if the Sun angle was not the same...which I don't think it was...then that might cause "changes" in the Martian topography.

R.A.F.
2004-Jun-07, 03:36 PM
There can be coloration differences due to the effect of dust storms.

OOPS!! I didn't "catch" this earlier, but you're absolutely right!!

So, lets see what we have, so far, to explain these Martian geological "changes"...

1. Image Resolution
2. Dust Storms
3. Image Angle
4. Sun Angle

Hmmm...I smell a non-mystery!

Tom Ames
2004-Jun-07, 04:02 PM
Another factor: aren't photos from the Viking orbiters and THEMIS taken with different peak spectra (different "filters" if you will)?

CJSF
2004-Jun-07, 04:05 PM
There can be coloration differences due to the effect of dust storms.

OOPS!! I didn't "catch" this earlier, but you're absolutely right!!

So, lets see what we have, so far, to explain these Martian geological "changes"...

1. Image Resolution
2. Dust Storms
3. Image Angle
4. Sun Angle

Hmmm...I smell a non-mystery!

Also,

spectral range and resolution
bit structure of image
image processing tools and techniques
image compression
map projection

I would broaden "image angle" to "viewing geometry"

Those of us in the image analyis and cartography fields know you can not do change detection without high precision spatial co-registration of the images involved. You also have to account for differences in atmosphere (dust in this case), lighting (sun azimuth and altitude), viewing geometry and sensor conditions at the time of acquisition. And that's with SAME SENSOR change detection. Throw in cross or mult-sensor issues and then you have to account for spectral differences, bit structure and any pre processing done on the data.

CJSF

R.A.F.
2004-Jun-07, 04:19 PM
Also,

spectral range and resolution
bit structure of image
image processing tools and techniques
image compression
map projection

I would broaden "image angle" to "viewing geometry".

I agree with all of the above. Boy, this "list" is just getting longer and longer. :lol:

craterchains
2004-Jun-07, 05:10 PM
Yes, FieryIce and I fully agree with all that must be taken into consideration concerning these photos, but we await patiently for you to catch up and then get on to actually examining the changes we note. =D>

We’ll check back in a couple days and see how it’s going. :D

Laser Jock
2004-Jun-07, 07:02 PM
So we have the following explanations of the differences between the two images:

1. Image Resolution
2. Dust Storms
3. Viewing Geometry
4. Sun Angle
5. Spectral Range and Resolution
6. Bit Structure of Image
7. Image Processing Tools and Techniques
8. Image Compression
9. Map Projection

At this point it would be CC's or FieryIce's job to:

1. Point out any specific differences between the two images.
2. Show exactly (without hand-waving) why none of the reasons listed above can explain the difference.
3. Provide a new and better explanation for the alleged differences in images.

Of course, why go to all that work when you can just be condescending.


Yes, FieryIce and I fully agree with all that must be taken into consideration concerning these photos, but we await patiently for you to catch up and then get on to actually examining the changes we note.

:roll:

JohnW
2004-Jun-07, 07:16 PM
Yes, FieryIce and I fully agree with all that must be taken into consideration concerning these photos, but we await patiently for you to catch up and then get on to actually examining the changes we note.
But you haven't noted any.

Are you going to present any actual data in this thread, or is it going to be like the one you started in "Against the Mainstream"?

CJSF
2004-Jun-07, 08:27 PM
I'll also note the THEMIS image in the OP is a shaded relief map, intended to show topography and is devoid of surface reflectance in any spectrum.

The Viking mosaic apparently shows surface reflectance in some visible or near visible wavelength, though the link in the OP to the image lacks any attributes. It also appears to have a severe histogram stretch, significant compression artifacts and image seam-lines.

There are better quality Viking images, that are map projected that one could possible compare MGS or Odyssey data to - though I would still be cautious without the raw and ancillary data to do a proper change detection.

You can bet that scientists both inside and outside of NASA are doing these sort of change detection analyses. I defer to their judgement.

CJSF

Chip
2004-Jun-07, 08:42 PM
1. Image Resolution
2. Dust Storms
3. Viewing Geometry
4. Sun Angle
5. Spectral Range and Resolution
6. Bit Structure of Image
7. Image Processing Tools and Techniques
8. Image Compression
9. Map Projection


This is a very good list. I hasten to add, perhaps along the lines of "Bit Structure of Image," that images drawn off the Internet are not very acceptible due to being compressed and low in the number of bits so that imformation is lost when enlarging. Access to original images or clear hard copies from the original sources would be a good start.

Among the experts in this area would be Malin Space Science Systems (http://www.msss.com/)

aurora
2004-Jun-07, 10:51 PM
under the topic of reality, though (rather than comparing global-scale images in different wavelengths and getting excited about observed differences), I did recently read an article on the apparent wet streaks on Mars (the ones that appear to come out of a crater wall and run down into the bottom, and are darker than the surrounding terrain).

They've found a number of new ones that have occurred since close up images were taken from orbit. So whatever mechanism causes them is still happening. The scale of these, though, is much smaller than Valles Marineris or Olympus Mons :lol:

There is still some debate about whether it is water or whether it is a dust flow.

Now I have to remember where I read it. Mercury? S&T? Anyone else see the article?

Edited to add a link to a similar article:

http://mars.jpl.nasa.gov/gallery/martianterrain/E3-2374_M3-6336subs_100.html

01101001
2004-Jun-08, 12:38 AM
I did recently read an article on the apparent wet streaks on Mars (the ones that appear to come out of a crater wall and run down into the bottom, and are darker than the surrounding terrain). [...]

There is still some debate about whether it is water or whether it is a dust flow.

[...]

http://mars.jpl.nasa.gov/gallery/martianterrain/E3-2374_M3-6336subs_100.html
Trouble is, those dark streaks are seen not only on crater walls, but also on butte slopes (http://www.msss.com/mars_images/moc/7_19_99_fifthMars/18_slopes/). I could almost see the ones in crater walls being supplied from aquifers in the surrounding plain, but you'd think the buttes would have weeped themselves dry long ago.

Knowing what we know about the patina of light-covered dust over darker stuff seen in so many places on Mars, it's a lot easier to imagine all those dark streaks are landslides.

I guess time will tell.

Chip
2004-Jun-08, 03:11 AM
I did recently read an article on the apparent wet streaks on Mars...the ones that appear to come out of a crater wall and run down into the bottom...
...it's a lot easier to imagine all those dark streaks are landslides...I guess time will tell.

I read a piece in Sky & Telescope with photos that looked like water seeping down. One theory was that a layer of underground ice was making mudslides on the crater wall where it intersects with the exposed slope, but it could also be dusty landslides as 01101001 said.

BTW: Here is a picture that shows the surface of Mars having been altered artificially by a advanced civilization (http://www.lifeinuniverse.org/noflash/images/vl1_11d128.gif). :wink:

craterchains
2004-Jun-08, 03:33 PM
Hope everyone has the idea now that when looking at these photos one has to take into consideration what other factors may be causing what appears to be changes on Mars between these photos. That being all stated and presented now brings us to the actual examination of the photographs content.

Examine the area C-7 for changes and comment on what you note.

CJSF
2004-Jun-08, 05:29 PM
Hope everyone has the idea now that when looking at these photos one has to take into consideration what other factors may be causing what appears to be changes on Mars between these photos. That being all stated and presented now brings us to the actual examination of the photographs content.

Examine the area C-7 for changes and comment on what you note.

As I have already said, the THEMIS image you cite is a shaded relief map, showing NO SURFACE REFLECTANCE FEATURES. The area may be varied in the spectral wavelenths of the Viking image but have little topographic variablility, or that variablility might not show on the shaded relief map due to the chosen light direction or perhaps the elevation post spacing in that area. You would have to compare VISIBLE reflectance data (in similar wavelengths) from MGS or Odyssey with the Viking image. NOT a shaded relief map.

The same site as the OP THEMIS map has the option to switch to an albedo map, but I'd advise against using this as well, since we don't know if the spectral range of the Viking imagery matches what was used for albedo calculations in the THEMIS map.

CJSF

aurora
2004-Jun-08, 05:38 PM
As I have already said, the THEMIS image you cite is a shaded relief map, showing NO SURFACE REFLECTANCE FEATURES.

I fear you may be doing this:

](*,)

Tom Ames
2004-Jun-08, 05:40 PM
Hope everyone has the idea now that when looking at these photos one has to take into consideration what other factors may be causing what appears to be changes on Mars between these photos. That being all stated and presented now brings us to the actual examination of the photographs content.

Examine the area C-7 for changes and comment on what you note.

I think the point is that such comparisons are meaningless.

For example, look at photos of the Earth at visible (http://www.ssec.wisc.edu/data/g9/latest_g9vis.gif) and infrared (http://www.ssec.wisc.edu/data/g9/latest_g9ir.gif) wavelengths.

How much time would you spend comparing the details of these photos?

(And this pair has virtually none of the discordances of the pair you presented above.)

Eye-Zee
2004-Jun-08, 06:48 PM
On their website, craterchains and his group ask questions like "Where did the companion mountain to Arsai [sic] Mons go?" in reference to the Viking mosaic he posted. The duplicate Arsia Mons is a painfully obvious error from hand-mosaicking of low resolution Viking images with poor or no cartographic control. This is the level of rigor involved in all of the investigations I have seen him present. Take it with all the seriousness it deserves.

Edit: The mosaic they call Viking from 1976 at the top of the thread is in fact Mariner from 1971 - the poor cartographic control is even less surprising. I should have realized.

Edit2: My edit stands corrected (by craterchains' post below). Viking mosaic after all. My other comments remain.

craterchains
2004-Jun-09, 03:24 PM
Tom
I think Meteora may enjoy your weather sat photos.

Eye Zee your problem is not with our cartographic skills, but with your reading skills.
Quote from that Plate 7 page (http://daac.gsfc.nasa.gov/DAAC_DOCS/geomorphology/GEO_10/GEO_PLATE_P-7.HTML)at that NASA site. “shown in the Plate as a mosaic of Viking Orbiter images.” Thank you for bringing up this point, as we did have the data credit wrong at our web site. But the image credit at the start of this thread is correctly stated. Here is a MSSS page (http://www.msss.com/mgcwg/mgm/about_processing.html) you may enjoy also.

Laser Jock
To bad we didn’t have a laser altimeter on the earlier missions isn’t it?

What I do find most peculiar is the lack of actual discussion of the image’s contents, which is the intent of this thread. Granted it is a good idea to take into consideration (As I have already stated and agreed with.) the differences in image acquisition properties.

And still no discussion of the image area C-7?

Tom Ames
2004-Jun-09, 05:20 PM
Tom
I think Meteora may enjoy your weather sat photos.

Eye Zee your problem is not with our cartographic skills, but with your reading skills.
Quote from that Plate 7 page (http://daac.gsfc.nasa.gov/DAAC_DOCS/geomorphology/GEO_10/GEO_PLATE_P-7.HTML)at that NASA site. “shown in the Plate as a mosaic of Viking Orbiter images.” Thank you for bringing up this point, as we did have the data credit wrong at our web site. But the image credit at the start of this thread is correctly stated. Here is a MSSS page (http://www.msss.com/mgcwg/mgm/about_processing.html) you may enjoy also.

Laser Jock
To bad we didn’t have a laser altimeter on the earlier missions isn’t it?

What I do find most peculiar is the lack of actual discussion of the image’s contents, which is the intent of this thread. Granted it is a good idea to take into consideration (As I have already stated and agreed with.) the differences in image acquisition properties.

And still no discussion of the image area C-7?

Why don't you tell us what you think about C-7, instead of fishing for some vague agreement?

Irishman
2004-Jun-09, 06:33 PM
The reasons no one has bothered to discuss the image comparison you want is precisely the reasons they've listed for why those comparisons would be difficult at best and meaningless for the most part.

Also, I would prefer for you to spell out specific differences you think you see.

However, in the spirit of looking for comparisons and proving a different opinion prior to you revealing yours, I've stared at the region in question. Cross mapping the two images is difficult because the gridlines are only on one image, and because of the stretched angle they don't overlap, but I've managed to see what compares to region C7. Here is what I see:

First locate the region in question on both images. On the second image, it is located above the gash, centered in the double groove between the fractured/cratered left and the tiers of the middle. If I could describe the shape of the gash, I might suggest it resembles a submarine, with the conning tower in the middle including a large observation platform, and the nose projecting forward to the spiderweb crater on the left. Thus the C7 zone is above the middle of the nose.

Just to the right you can see a bumpy ridge line and a smooth valley with the shape of a boot, toes pointed right, kinda like Louisiana and above it Arkansas. The "Texas @ Oklahoma border" stretches up the left of the valley, which runs right along the edge of the right gridline.

Looking at the Viking mosaic, I can see the jagged ridgeline that runs down the right of that valley, and the shadowy shape of the left ridgeline. I can't really make out the boot shape very well, but I see the feature of the connected rough valley off the toe.

Now that I've located the region in question, I see in the Viking image what looks like a dark ridgeline running west across the region. Okay. What is in the MOC image? At first glance it looks smooth with a small crater at the lower middle. Closer investigation, however, suggests there is some texturing from highland ground to the south of that zone and lower elevation to the north. One can in fact see a hint of a slopeline between the two regions that matches fairly well with the ridgeline in the Viking image. The crater itself is not specifically visible in the Viking image, but the dark and light colorations and low resolution make comparison too difficult.

In summary, there is nothing distinctly different between those two images in the region in question.

R.A.F.
2004-Jun-09, 08:22 PM
Eye Zee your problem is not with our cartographic skills, but with your reading skills.

Couldn't you have put this in nicer terms? You can tell a person he's wrong without being insulting. [-X


What I do find most peculiar is the lack of actual discussion of the image’s contents, which is the intent of this thread. Granted it is a good idea to take into consideration (As I have already stated and agreed with.) the differences in image acquisition properties.

I don't know why you would find this "peculiar". You've "basically" answered your 1st sentence question in your 2nd sentence...the "differences in image acquisition properties" are exactly why these 2 images "look" different.

craterchains
2004-Jun-10, 03:02 AM
We now have two points of interest in the topography of Mars from the 70’s to the turn of the century. Areas E/F-1/2 the cross lines where there appears to be a missing sister Mons that Eye-Zee mentions from the web site. The next one in question is that of the gash or canyon at the top area of C-7 as mentioned by Irishman.

Eye-Zee makes a good point about that it may have been a bad overlay from NASA employees? I have my doubts about that. At least I hope that they would be better than that by far. Any one care to try and discover if it is a faulty alignment of pictures or is it a missing Mons? Or at least a very diminished sister Mons.

Irishman points out a couple differences, but that crevice or gash or canyon that is in the upper area of C-7 on the Viking image is greatly reduced by 30 years later. If not completely gone. If this is a picture malfunction, it’s a big one that should have been corrected. So is this bad astronomy or what?

There is two points of interest, and I will add a third. D-8 upper right area, there appears to be a very diminished crater. The right of the two shown in the 1970’s photos is now greatly diminished 30 years later. I am thinking water caused these features to all but disappear. Massive flooding would be reasonable. But that would mean that there were oceans of water on Mars in very recent times.

R.A.F.
2004-Jun-12, 03:59 PM
I am thinking water caused these features to all but disappear. Massive flooding would be reasonable. But that would mean that there were oceans of water on Mars in very recent times.

Do you see the problem with "that" line of reasoning? I know I do.

There is NO evidence of "oceans of water" in either image. Yet, "sometime" within that 30 year span, there was "massive flooding"? And now, all that water has disappeared?

Sorry, but that doesn't make any sense.

craterchains
2004-Jun-14, 01:09 AM
Not to worry there R.A.F. there is no reason to be sorry because it sure didn’t make much sense to me either at first. Yes, there are some major problems, only not with the line of reasoning as yet that I am aware of. It just “appears” that my reasoning is not correct, for now. Now to try and prove that. FieryIce and I have only been trying to reason on this for a few months in our spare time.

I quote you;

There is NO evidence of "oceans of water" in either image. Yet, "sometime" within that 30 year span, there was "massive flooding"? And now, all that water has disappeared?

You state there is NO evidence of “oceans of water” in either image.
Would you care to make a small wager on that? Say a bottle of Pinch Scotch? (If I win, and if you win?)

But we are skipping ahead of the necessary exploration of these and many other images before we can ascertain “when” those oceans of water “were” there, and what happened to that water. 8-[

The intent of this thread is to try and make sure that there are indeed changes to Mars in very recent times. There are over a dozen major features that have changed or have all but disappeared in thirty years. A few new craters, a few that are no longer there. Large areas appear to have changed between those old photos and the ones we see today.

I can understand the reluctance of many to even comment about this. But, that doesn’t make the changes go away. Nor does it make my assessment incorrect that water probably made those changes. And like you said R.A.F., what water? Yes there are other possibilities such as volcano’s ash and debris. Only the patterns of flows don’t work out and it is up hill for the most part where these changes are noticeable. Here is another link (http://ltpwww.gsfc.nasa.gov/tharsis/mola.html) that can help with exploring for free what’s on the web. The data sets are far too costly for us. :([/url]

Musashi
2004-Jun-14, 01:17 AM
Wouldn't wind be a more likely culprit than water?

Kesh
2004-Jun-14, 06:56 AM
We now have two points of interest in the topography of Mars from the 70’s to the turn of the century. Areas E/F-1/2 the cross lines where there appears to be a missing sister Mons that Eye-Zee mentions from the web site.

There doesn't seem to be anything missing to me. Observe the large raised area just "south" of the Mons in the newer image. Compare its location to the so-called sister Mons in the Viking image, and I'd say that's your culprit. It's less striking because of the rather steep angle the Viking image appears to have been snapped at.


The next one in question is that of the gash or canyon at the top area of C-7 as mentioned by Irishman.

Eye-Zee makes a good point about that it may have been a bad overlay from NASA employees? I have my doubts about that. At least I hope that they would be better than that by far. Any one care to try and discover if it is a faulty alignment of pictures or is it a missing Mons? Or at least a very diminished sister Mons.

Irishman points out a couple differences, but that crevice or gash or canyon that is in the upper area of C-7 on the Viking image is greatly reduced by 30 years later. If not completely gone. If this is a picture malfunction, it’s a big one that should have been corrected. So is this bad astronomy or what?

Okay, I think I've found this one as well.

Note, in the Viking images, that the gash appears some distance to the right of the small central Mons, the last in that crescent of mounts from the left of the images. If you trace the 'gash' downward, you come to a rather recognizable section of the canyons "south" of the feature. (To clarify, it's a circular canyon almost the shape of a human eye. Oh no! :D )

Now, examine the newer image. To the right of that mount, and above that same feature, you can make out a ridge, as if there's a sharp change in elevation between the "west" and "east" portions of the land. You can actually follow this ridge from A9 down to the 'eye' in D8. Then, follow the canyons to the left, and you'll see the ridge pick up again in E4, where it continues "west" into E3 and then "south" into F3, off the map.

I'd say what we're looking at is some kind of natural ridge, or other steep elevation change in the landscape, rather than an actual gash. If I had to guess (and it's a wild one), the "western" half of the image may have once been a sea bed, and the elevation change is either the shoreline or the 'continental shelf'. That's sheer speculation though.


There is two points of interest, and I will add a third. D-8 upper right area, there appears to be a very diminished crater. The right of the two shown in the 1970’s photos is now greatly diminished 30 years later. I am thinking water caused these features to all but disappear. Massive flooding would be reasonable. But that would mean that there were oceans of water on Mars in very recent times.

Already pointed out as the 'eye' feature. It's not diminished at all, simply the Viking images have thrown shadow onto the feature enough to make it seem larger, as well as blurring the outline of the feature which makes it more difficult to objectively determine its size.

My personal theory (as a non-geologist) is that we may be looking at a coastline, accompanied by a river delta (the canyons in the lower-middle of the image). The Mons' would then be islands (or underwater peaks) in an ancient sea bed.

As I said, though, this is really just a layman's look. I see no evidence of major erosion between the two images, and any water that existed on Mars would have been gone long before even the first one was taken, in order to create such features.

R.A.F.
2004-Jun-14, 03:03 PM
...and any water that existed on Mars would have been gone long before even the first one was taken...

This is the point I was "trying" to make in my post. Any "oceans" on Mars have been dried up for a long long time. Certainly oceans didn't "spring up" and then disappear between the time these two images were taken.

Thanks, Kesh for making it "a bit clearer"...and a belated welcome to the board!

Irishman
2004-Jun-14, 06:20 PM
Kesh, look closer at my post.

The long ridgeline you describe is evident in both, and not the feature in question. Just to the left of the "eye" is a valley shaped like a boot. Looks kinda like Louisiana. Just above it the valley looks a bit like Arkansas. The left ridgeline of the valley is just about under the 7/8 line.

The "missing gash" is right through the middle of zone D7. In the Viking image there is a change from bright to dark. There appears to be a distinct ridge line.

In the MOC image there is not a distinct ridgeline like a cliff. However, elevation does not appear to be flat. I contend that the image quality of the Viking mosaic is too poor to make valid comparisons.

craterchains
2004-Jun-14, 08:47 PM
I changed the picture so it now has several possible areas of change that FieryIce and I have noted for starters. That should help keep down the future confusion. :D

Eye-Zee
2004-Jun-14, 10:02 PM
Here's my take on this "analysis." The whole comparison is ridiculous on it's face, since we are being urged to compare a low resolution, poorly controlled, hand-built photomosaic with a digital topographic relief basemap.

However:
A: Apparent ridge on Viking in Fortuna Fossae. Mostly an albedo feature. Visible on Themis basemap if you go to the site, click the map onto Albedo and zoom in a bit.

B: Ophir Chasma. No difference obvious. Zooming in both the Topo and Albedo Basemap
shows nothing you wouldn't expect from differing resolutions, illuminations and data types.

C: Duplicate Arsia Mons in Viking mosaic. Obvious mosaicking error. There are plenty of Viking era images of Arsia Mons and it's always been a single volcano.

D: Tharsis Tholus. No differences you wouldn't expect from different data sets.

E: Crater Fesenkov. Seen in Viking era. Likely off the Viking map shown.

F: Echus Chasma. No differences you wouldn't expect from different data sets.

G: Lunae Planum. Viking shows E-W albedo trends. Themis topo base map shows N-S structural trends. Themis basemap shows the E-W albedo markings also when toggled to "Albedo" intead of "Relief"

H: Kasei Valles. Valley with outflow channel landforms. No differences you wouldn't expect from different data sets.

I: Ceraunius Fossae. The N-S trending tectonic structure doesn't show particularly well in the low res albedo map, but does in the topomap, since they are primarily topo features. Viking saw the structure at higher.

J: Crater Poynting. A low relief crater, the Viking Mosaic does not capture it well, but other Viking imagery does.

Every single putuative difference pointed out is either no difference at all, obvious cartographic errors in older datasets, or misinterpretation of datasets which are meant to show completely different things.

Kesh
2004-Jun-15, 07:09 AM
Irishman, I apologize. I must have misunderstood what you were pointing to. And it appears craterchains agrees with me as to the gash/ridge in my conclusion, as now the "gash" and the "ridge" are both labeled object F.

Though I have to admit, craterchains, I'm a bit upset. It's not cool to switch photos midway through the thread like that. And how did you manage that, anyway? Hosted on a site of yours?

Either way, could you put the originals back, and post new links to the labelled photos? That way, we can see clearly what this discussion is about.

That said, Irishman, I'm still not sure what object you're pointing out, if you're not referring to object F. I'll keep examining the original Viking photo, but I'm just not seeing it right now.

{Edit} Okay, I see what you mean, now. It appears to be the object craterchains has labelled A. Is that correct?

Kesh
2004-Jun-15, 07:26 AM
...and any water that existed on Mars would have been gone long before even the first one was taken...

This is the point I was "trying" to make in my post. Any "oceans" on Mars have been dried up for a long long time. Certainly oceans didn't "spring up" and then disappear between the time these two images were taken.

Thanks, Kesh for making it "a bit clearer"...and a belated welcome to the board!

Thanks! I've been lurking for several months, and just recently decided to start posting. Wanted to get a feel for the board first. :)

Hopefully, I can make some good contributions to the board. I'm just a layman with some amateur experience and a few classes, but hopefully that's good enough I don't make a complete idiot of myself. 8)

R.A.F.
2004-Jun-15, 02:38 PM
Starting out a "tad" off topic, but I'll "tie" it back in...I promise. :)


Wanted to get a feel for the board first. :)

I think you'll find that this is the best board on the web, IMO. (I was "lucky" in that this is the first board I'd ever posted to, and now I'm spoiled.)


Hopefully, I can make some good contributions to the board. I'm just a layman with some amateur experience and a few classes...

That's the beauty of this board...we have folks here rangeing from interested pre-teens, to seasoned scientists...and though I'll offer my opinions, (at the drop of anyone's hat), the most important aspect of this board, IMO, is the fact that there is a lot of learning going on here. (I know I learn something new here "almost" every day).


but hopefully that's good enough I don't make a complete idiot of myself. 8)

Don't worry, I make an idiot of myself at least once a week. :) (HEY, you, in the back, stop laughing.:))

And what is this board "about"?...I think that craterchains "case" is the perfect example. (See, I've "wandered" back on topic...told ya all I would.:)) He has proposed that there were "catastrophic" changes on Mars, taking place within a 30 year period. As "evidence", he provides 2 images. Yet, he doesn't seem to take into account the fact that these images were taken by spacecraft whose technologies are separated by 30 years.

It's just as Eye-Zee posted. We're being asked to compare 2 images of differing resolutions, etc. and make conclusions based on that. I'm beginning to wonder what we would see if we had sent another Viking to Mars, in the late 90's, and taken images of the same area. I'm willing to bet that they would look "essentially" the same. The "differences" in the images are "basically caused by" the "differences" in the spacecraft and differences in processing. There's really no mystery here...at least no "objective" evidence of one.

Everyone is welcome on this board...but...

If a person comes here, and has a "theory" that supposedly reflects reality, then the folks here are going to want to see some evidence that the "theory" isn't so much hot air.

IMO, craterchains has not been able to provide that evidence. His "imagined differences" in Martian geography are more than likely simple differences in resolution.

Irishman
2004-Jun-15, 04:29 PM
Kesh, yep, point A. No problem, just keeping on the correct feature.

Eye-Zee, nicely done.

craterchains
2004-Jun-15, 08:42 PM
Sorry about the image change taking a few by surprise, for conservation of band width, both here and at our site, please download the photos to your desk top for perusal off line.
Here are a couple links that will help, and there are literally hundreds of photos available with searches for them. We only post a couple relevant ones for topic starters. We are not trying to lead anyone down any particular path, EXCEPT one of personal discovery. As stated, we are still acquiring and examining photos for relevant possibilities of changes. If any are interested in pursuing this, and not so lazy to search for photos instead of having it all handed to them on a silver platter with a silver spoon to eat with, they will find some great food for the mind and the satisfaction of self discovery. :D

I am in Seattle for a couple days working at a high-speed connection as at the boat in Tacoma I only have 26.4kbs speeds. Will adjust the photos when I get back to the boat and provide the first image set we put up. Please copy to your desktop, as we will be changing that one photo to a couple others as we progress with this investigation. No theory, no case, and questioning many things before anybody should state anything as yet. Agreed it could be just the differences between imaging techniques, could be. Or is it really a difference in actual changed image content? :-?

R.A.F.
2004-Jun-15, 09:20 PM
We are not trying to lead anyone down any particular path, EXCEPT one of personal discovery.

Well, I've personally discovered that this thread is going "nowhere".


If any are interested in pursuing this,...

No, not really. You're "theory" just isn't that interesting.


...and not so lazy to search for photos instead of having it all handed to them on a silver platter with a silver spoon to eat with...

Wait a minute...you've come here with a "theory"...it's up to you to prove it. We're not going to do your "work" for you.


...as we will be changing that one photo to a couple others as we progress with this investigation.

Oh that's just great! So at any time you can change the images, to suit your whim? I don't think so.


Agreed it could be just the differences between imaging techniques, could be.

Resolution!!


Or is it really a difference in actual changed image content? :-?

Well, or course the image content is "different", but that's not all you're saying. You're saying that there is actual geologic changes evident when you don't have the data to support that contention.

I liken it to myself...trying to read small print without wearing my glasses. Is the print on the page the same even though it "looks" out of focus to me?? Well, of course it is!

The same kinda thing applies here, IMO. It's your job, craterchains, to prove that "differences in resolution" can not be the cause of the "perceived differences". So far, you have not done so.

StormSeeker
2004-Jun-16, 02:38 AM
My .02

There is no way to resonably compare the two images that isn't purest speculation. There is simply no way to differentiate between what might be compression artifacts, noise in the original image or who knows what. A cursory comparison isn't even really possible without the same picture geometry. They're not even the same type of image!

You might as well try to compare a polorid taken from a hot air baloon and a landsat near-infrared image, and try to find the "Changes", it's simply bad science.

craterchains
2004-Jun-16, 03:52 AM
Thank you all for your comments.
I have decided against further discussion until better image interpretation data can be obtained.

Meteora
2004-Jul-09, 02:13 PM
Tom
I think Meteora may enjoy your weather sat photos.

Yes, nice. Of course, I get to see images like that (except farther east) at work "all the time." Animated, too! 8)


I have decided against further discussion until better image interpretation data can be obtained.

Darn. I guess I don't get to mention how much difference it made to our satellite interpretation techniques when the resolution was increased quite significantly when the latest GOES came on-line. :cry:

Or do I? :D

Hmmm... I see that "craterchains" has been banned. Oops....

R.A.F.
2004-Jul-09, 03:59 PM
Hmmm... I see that "craterchains" has been banned. Oops....

Well, his partner in these "investigations" and the poster who started this thread...fieryice is still here...maybe she'll be willing to discuss this "stuff".