Mars observed in 1976 by the Viking Orbiter then observed again by Mars Odyssey mapping (2001-04).


Viking Orbiter Image Themis, Thermal Emission Imaging System

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!

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 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.

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!

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"The facts gentlemen, and nothing but the facts, for careful eyes are narrowly watching." Isaac Asimov

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

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

"Many astronomers" are? You're probably thinking of Percival Lowell.

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.

__________________
It's not what you know or don't know, but what you know that isn't so that will hurt you. Will Rogers
http://www.craterchains.com/ns/nspage.html

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.

__________________
Old laser physicists never die, they just become incoherent.
These days, every Tom, Dick, and Harry thinks he knows what a photon is, but he is wrong. - Albert Einstein

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.

__________________
"The facts gentlemen, and nothing but the facts, for careful eyes are narrowly watching." Isaac Asimov

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!

__________________
"The facts gentlemen, and nothing but the facts, for careful eyes are narrowly watching." Isaac Asimov

Another factor: aren't photos from the Viking orbiters and THEMIS taken with different peak spectra (different "filters" if you will)?

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

__________________
Two years ago moved from my town
I was looking up past the city lights
But the city lights got in my way

See the constellation ride across the sky
No cigar, no lady on his arm
Just a guy made of dots and lines

-from "See The Constellation"
by They Might Be Giants

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

__________________
"The facts gentlemen, and nothing but the facts, for careful eyes are narrowly watching." Isaac Asimov

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.

__________________
It's not what you know or don't know, but what you know that isn't so that will hurt you. Will Rogers
http://www.craterchains.com/ns/nspage.html

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.

:roll:

__________________
Old laser physicists never die, they just become incoherent.
These days, every Tom, Dick, and Harry thinks he knows what a photon is, but he is wrong. - Albert Einstein

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"?

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

__________________
Two years ago moved from my town
I was looking up past the city lights
But the city lights got in my way

See the constellation ride across the sky
No cigar, no lady on his arm
Just a guy made of dots and lines

-from "See The Constellation"
by They Might Be Giants

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

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

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/mar...6subs_100.html

Trouble is, those dark streaks are seen not only on crater walls, but also on butte 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.

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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. :wink:

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.

__________________
It's not what you know or don't know, but what you know that isn't so that will hurt you. Will Rogers
http://www.craterchains.com/ns/nspage.html

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

__________________
Two years ago moved from my town
I was looking up past the city lights
But the city lights got in my way

See the constellation ride across the sky
No cigar, no lady on his arm
Just a guy made of dots and lines

-from "See The Constellation"
by They Might Be Giants

I fear you may be doing this:

](*,)

I think the point is that such comparisons are meaningless.

For example, look at photos of the Earth at visible and infrared 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.)

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.

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“The simplest schoolboy is now familiar with truths for which Archimedes would have sacrificed his life.” – Earnest Renan

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 pageat 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 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?

__________________
It's not what you know or don't know, but what you know that isn't so that will hurt you. Will Rogers
http://www.craterchains.com/ns/nspage.html

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

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.

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

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.

__________________
"The facts gentlemen, and nothing but the facts, for careful eyes are narrowly watching." Isaac Asimov

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.

__________________
It's not what you know or don't know, but what you know that isn't so that will hurt you. Will Rogers
http://www.craterchains.com/ns/nspage.html

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.

__________________
"The facts gentlemen, and nothing but the facts, for careful eyes are narrowly watching." Isaac Asimov

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;
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 that can help with exploring for free what’s on the web. The data sets are far too costly for us. [/url]

__________________
It's not what you know or don't know, but what you know that isn't so that will hurt you. Will Rogers
http://www.craterchains.com/ns/nspage.html