Hi,
Perhaps it's mentioned and discussed many times before, anyhow.

There are lots of sites discussnig the tubes of mars (e.g. http://ida.wr.usgs.gov/fullres/divid.../m0400291a.jpg )

I'm not gonna talk about underground irrigation systems, or submerged ufo-rollercoasters.

Could it be that these things are ICE, since they do look 'glassy'? If water, assuming there would be enough water underground, turns into ice as soon it hits the Martian surface, could it than be that the tubes are remainings of water-'geisers', that changed into ice tubes over time?

If so, it could also be a place to find running water inside, wouldnt it?

They're not tubes. They're canyons filled with fine sand, sculpted into rippled dunes by the wind.

The idea behind your thinking is not completely improbable though. Mars having no tectonic movement anymore would render any geysers it did have into barren ice holes that could open up into vast underground caves. :wink:

In a few days, I will have a page up explaining these features. They are valleys with wind blowing down them. The ridges are lines of dunes. The glassy appearance is an illusion due to the way the brightness is displayed in the image.

Which you see in virtually every canyon that MGS has photographed.

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Hmmmm. Moral dilemma, BA says they're dunes, Sir Arthur C. Clarke says they're "glass worms." Who do you believe?

Heres one that looks like it broke open and spilled all over the plains:

http://www.highmars.org/niac/educati...es/blobs01.jpg

The original with context lives here:
http://www.msss.com/moc_gallery/m19_.../M2101816.html

Mighty odd looking. Reminds me of white chocolate chip macadamea cookies...

Yum!

Capthraw the Space Lizard

[-(

I just don't buy it. I've looked at the so-called "canyons with dunes" over and over again and the explanation does not wash. Neither does the argument that they are concave and not convex. I am familiar with lighting and shadow effects through study of art and photography. Just use your eyes for Pete's sake.

I am generally a skeptic about extraterrestrial life. My friends consider me an inveterate debunker, but this explanation I cannot buy into. These formations were either made by some geological process that I cannot fathom, or there is something organic that made them. I have never seen anything that looked like this that wasn't of organic origin.

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8-[ What is the scale of those images???

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I'd be more interested if they didn't seem to show up just about everywhere. They seem to be a commonplace wherever there's any sort of canyon or channel. That makes me think they're the result of winds rather than anything else.

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Mars Global Surveyor MOC Images

The resolution for m0400291 is 3.60 meters. So the image, if my math is correct, is 3.14 km by 4.09 km and the feature at its widest is about 250 meters across and at the narrow point is around 50 to 70 meters. If anyone has a decent graphics program, they should be able to get a better estimate.


Scott

I don't know what your experience with images is, but it is completely obvious that these features are canyons with dunes.

Perhaps you need to read a little more on images taken from orbit.

They are not and cannot possiibly be CONCAVE valleys nor are the high albedo features any sort of aeolian nor fluvial dune form.

In the next 24 hours I will create a new thread here demonstrating why this is not reasonable and contradicts all evidences. The burden of preconceived expectation can be just as misleading and destructive to objective analysis as imagination unbound by technical understanding.

Without a doubt many persons across the Internet have held forth common dune trains constrained in topographic lows as being the same as these convex "Tubes". Certainly there are undeniable correlations betsween those high albedo arcs and transverse dunes, buit only if examined superficially. However the MO4-00291 image is actually an uncommon image in that it has an array of fortunate details which, along with other image details, helps define these contested features as being more unique.

Tripp:

What experience do you have in desert geomorphology, aeolian landforms, and the landscape of Mars that allows you to say that these features are not transverse dunes in canyons? I have seen lots of dunes in terrestrial deserts, and lots of canyons and valley floor deposits. I have even spent a lot of time looking at Martian images. These features are geologic in origin beyond any shadow of doubt.

Jon

I've studied geomorphology and petrology and have empolyed these backgrounds in interpretation of remote geophysical surveys such as GPR, seismic refraction, magnetometer and electromagnetometer. While admittedly I have not spend so much time actually in desert environments, I have examined a vast portion of desert from satellite

Given you're a geologist youself, I gather that you agree that the recognized convex appearance (even acknowledged by NASA) is entirely an optical illusion without any foundation in reality?

Also I am somewhat confused by your concluding statment, "These features are geologic in origin beyond any shadow of doubt". Is the implication that if these features are not aeolian transverse dunes in concave valleys then these features are not geologic in origin?


Do you see nothing at all incongruous to the interpretation of these as transverse dunesl? Keep in mind that the JPL, Media Relations Office made indirect commentary on these features on May 22, 2000:


Even JPL scientists wish they knew what processes are involved to cause these features.

Yes, the convex appearence is entirely an illusion, as far as I can see. OK, if these are not dunes then this does not rule out other geological processes. As to the JPL quote, unless I can read it for myself I can't place it in context. But science by press release is a very dangerous thing. You may (or may not) remember the infamous statement in a popular NASA book after Mariner 2 that spoke of carbonhydrates on Mars, thus giving support to a whole generation of Velikovskyites.

Give a link to the press relase and I can comment. Incidently I have worked on the ground in deserts on Australia (Great Victoria, Simpson, and Strzelecki, the US (southern Utah) and South America (Atacama and the Altiplano). As I child I did travel through Jordan but I am not sure I can include that

Jon

Maybe it is a giant snowboard park... :wink:

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If you go into a program like Photoshop and play around with brightness and contrast options a bit, you can see both canyon walls and in the middle is the "glass worm" or whatever you want to call it.

http://geocities.com/xbck1/canyons.jpg

Copy and paste that link; Geocities hates linking.



Edit: spelling

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Jon,
You are saying that "as far as you can see", the convex appearance is an illusion? But your inclination is to see that illusion youself yet you recognize it as not being real how, by what detail? Many natural forms represent crescent arcs other than dunes, such as glacial crevasses and p-waves or longitudinal pressure waves in pahoehoe-type fluid lava flows, to name a couple.

It would be unfortunate for you to deny the convex nature of this image and force an inverted perspective merely to accomodate what would be the most likely scenario of these arcs being transverse dunes constrainted within narrow valley walls, especially if that convex shape is supported. Is there some other conspicuous detail that indicates these are concave other than expectation?

I have seen a few aerial geologic images that resulted initially in my improperly interpeting lighting resulting in positive and negive reliefs being inverted. One of these images was particularly resilient and I had to actually walk away from it for several hours and approach the image in an upside down, inverted orientation before my mind was freed from its prior prejudice.

These problematic images all had some things in common: they had insufficient or poorly defined detail prohibiting me, personally. from interpreting the terrain properly.



This image under consideration has a wide variety of structural features which serve to clearly indicate the lighting to the mind's eye, not the least of which is an enormous tri-radiate valley system with each of the 3 arms serperated by nearly precise 120 degrees of arc. This 120 degree arc separation between the 3 valley arms ensures that some vectoral aspect of a 360 exposure to light source is represented across the 3 valley arms. Despite this widely varied orientation equally dispersed across the compass, each of these 3 valleys similarly represents the features within as convex in shape. That is a lot of "optical illusion" for even the best of magicians to maintain.

Jon, I have one ultimate question for you:

Short of physically being present on Mars and overlooking these features in person, what demonstration or test would be sufficient to indicate to you that these features in this image are not an optical illusion?

I'm not John, but wouldn't a stereo pair, or anaglyph, of the feature demonstrate its concavity? For instance, I can temporarily fool my brain into thinking this (large)Mars Express image of a volcano is a bunch of stacked domes, until I concentrate on things at different heights, say the rim and the floor, especially zoomed in to exaggerate depth, and my eye-cross is noticeably wrong. The parallax demands that it be concave.

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"Tube" anaglyph
http://marsunearthed.com/Anaglyphs/Tube/Tube_3D.htm

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Thanks, PeteB, I was getting to that.

The area originally recognized as the primary "tube" anomaly first imaged on August 11, 1999 as image number M04-00291 was re-imaged on October 27, 2002 as image number E21-01421 and has somewhat recently been made available on the Internet and become recognized to those having interest in this discussion.

This second image, E21-01421. was used with the prior image, M04-00291, as stereo-optic pairs to construct the 3D anaglyph provided by PeteB, above.

E21-01421


While the resolution of this new image is somewhat less than the image taken almost 3 years previously ( 4.12 mpp as opposed to 3.07 mpp)as a result of the Emission angle being a highly angled 31° and the satellite altitude being somewhat greater, it does continue to demonstrate these features are, in fact, convex forms and not concave valleys with "dune trains" traveling their length or a "trick of light and shadow". It is a matter of some note that NASA has refrained from any and all comment on this not inconsequential fact with the new release of image number E21-01421, only having changed the image description from "fine channels" to now "Polygon trough with small bright bedforms."

(edited to add URL and further detail)

Huh? You mean concave. The registration is poor. Why? I had to rotate my head about 20 degrees clockwise, but when I did it was very clearly concave.

If not to you, are you sure you've got your red lens on your left eye?

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Well from the 3D image it seems clear to me that the image does indeed, as BA stated originally, show dune rifting along a valley floor casused by the fluid dynamics of the air flow down the valley itself. This impression is increased when you look at the upper right part of the picture. Here you can see light dune ridging in this shallow valley that vanishes as it opens out int the much wider areas in the center of the image.

You can see the same effect in the valley that heads right from the intercetion of the three valleys. As it rises up it psses over an open area (directly above the large crater) that has no dune ridges, but then they return as soon the valley once more closes up and narrows.

The final evidence here is that the dunes are much closer together the deeper the valley, indicating that the feature is caused by the vally itself and its depth. You can see this by comparing the dune distances in the very deep valley that heads down to the lower left hand corner with those in the other two valleys and the distances apart in the other three valleys as they raise up and sink.

Apart from that, the only trouble I had was finding my 3D glasses, and having to wear them upside down for a few seconds to realign the cones in my eyes so everything wasn't blue through my left, and red through my right.

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Tripp

We seem to be talking past each other, I fear.

Let me rephrase what I tried to state earlier. The common orientation of this image can generate the illusion of a convex structure. It is an illusion; the same that can make craters look like domes and volcanoes holes in the ground. I no longer see the illusion when I look closely at it or rotate the image so that the light comes from another quadrant. I am not forcing anything, it is simply what I see based on near 30 years of working with aerial photos and other imagery.

While processes can generate crescentic forms none of these apply here. First, the features are not crescents, even though they are curving. The crests tend to be straight; it is only the extremities that curve, in exactly the way one sees in transverse valley dunes. The center of the dune tends to move further than the limbs, because the wind velocity is higher.

The scale is too large to be flow features in lava, and they are not depressions, so they are not crevasses in ice. Furthermore there are none of the flow and morainal features one would see at the confluence of ice streams. I see nothing in this image that would require to be anything other than sand dunes.

What would convince me that the floor of these valleys is convex? A MOLA traverse would do nicely, or steroimagery from Mars express, or MARSIS data.

Jon

Actually the area you're describing has none of the evident features of a convex 'tube' nor a concave valley because the north wall of the valley has had a catastrophic collapse and landslide.



This landslide is even more evident in the most recent E21-01421 image as a result of the angle of view (Emission angle).

If these "dunes' were formed in this right (eastern) arm of the tri-radiate valleys as it is currently. then there would be no wind "fetch" distance or area of wind build-up to achieve sufficient force to form dunes in that reformed valley (the valley does not exist there to channel the winds). The predominant observation of such transverse dune trains ON MARS involves the wind speed being accelerated in narrow valleys or along scarps, where the valley mouth or scarp has "funneled" the winds and increased the speed through the valley canyon or scarp lengh. This is true because the atmosphere on Mars is only 1% of that of earth.. and gravity is also less, 1/3.. so that sands do not saltate, or cause other grains to bounce and become airborne as readily (having less mass and the wind speed cannot sustain what mass they do have). The net effect is that is that even gale force winds on Mars are only felt as mild breezes.



Detail of east valley arm in M04-00291, east of landslide


While the above image is arguably an extreme enhancement, it does show two features that are reasonable extractions from that image: 1) there is no longer any impression of a convex traversing the length of the valley and 2) there are in-line, linear features with a clearly positive relief above that of the surrounding terrain. Within the paradigm of these being dunes, these features would have to have been formed before the landslide and be somewhat "fossilized" (lithified) so as to not be disturbed by that collapse, with this fossilization somewhat explaining the positive relief as it provides a localized resistance to erosional forces. Yet within the dune paradigm, these features are entirely too close to one another and demonstrate no arc, being virtually straight lineations laterally, which is incongruous with transverse dune formation and migration. Within the paradigm that these are convex 'tubes', some maintain that the existance of these features while the vitreous tube itself is absent (collapsed/shattered), demonstrates that the 'arches' are far more resilient than the convex form ("tube") itself. Whatever happened to that visual impression of a convex form?

(more on dunes to come)




The problem with your statement is that there is no "common orientation" of these features we are all admittedly seeing as convex now across two images at highly varied angles of view (a 30° differential) . The tri-radiate valley arms vary by ~120° presenting different aspects to the illumination and despite this the impression of a convex shape perseveres in all directions of these valleys, even in the north limb when it curves to the east. THis is quite a lot different than the illusion of conveyed in BA's example of an impact crater appearing to be convex as a dome. Even that example, with minimal examination of the "dome-like' feature would indicate that it is, in fact, the concoidal depression of an impact crater. BA's examply mostly works because the two features are beside one another and, in so juxtaposing them, the light orientation is being played with and the interpretation of light from one direction (up to the north) forces the impression of a dome in the other image. This impression is added to by the fact that people prejudicially 'prefer' lighting from up and to the left; most of the false 3D created web art have the lighting oriented from up and to the left.

I honesly do not see your valleys when the image is reoriented upside down, sideways or whether I view it on a box or over rocks .. oops (sorry, Dr Seuss got ahold of me there). I've tried all these orientations and I will reiterate that the plausibility of these convex linear forms being false illusions of lighting is made virtually nil by the widely varying orientations of these features across what is now two seperate images where detail and terrain are more than sufficient to properly mentally interpret lighting and, thereby, relief.

The "dune" interpretation of these features is challenged when you recognize that these "dunes" are equally well defined in all 3 radiating arms. Such an equal dune definition would imply that the wind direction is equally strong, consistant and uninterrupted in all 3 directions up these 3 valleys .... and at the same time too, which is not reasonable at all. Furthermore the "dunes" still maintain definition on into the intersection of the 3 valleys, which should have turbulent winds even if only one valley had a definative, prevailing wind direction up its length, not to mention 3.




If you examine BA's comparison with the color image of transverse dunes Gorgonum Chaos, there is undeniably a resemblance of these arcs with dunes:



However the comparsion of these arcs associated with the 'tube' features with transverse dunes becomes more problematic with a more thorough examination.

references:
High Rez Image of Gorgonum Chaos
MSSS Gorgonum Chaos Page


If you notice the intersections of these valleys in the Gorgonum Chaos image, none of the intersections maintains the wind speed and direction to permit the continued advance of these dunes, with the exception of the one trending east-west, which is more-or-less linear. All the others show that the wind has insufficient 'fetch' to build up adequate force to create dunes. As indicated previously, this disagrees with what is evident in these curiously persistant convex 'tube' impressions, now across two seperate images at extremely diffierent angles of view.

There are other features in the "tube" images which are highly irregular as well, but none here has even broached those yet.

Good thing someone already introduced the re-imaging, eh? What is the matter with the stereo-optic pairs from MGS? (Added: I guess there is too much pixel stretch in the second image from the Emission angle being so much greater than the first, making it hard to correlate features for a good 3D pair. Ideally the angle offset of image pairs should be about 2°, not 30°. This is likely contributing to the difficulty in conveying the convex aspect in the anaglyph.)

(edited to sufficiently mimic the english language)

OK, so we both agree that this is a valley. That is a start.

Fetch is not really relevant to dunes. You are not dealing with a liquid-gas interface There is no reason why dunes cannot start down wind of an obstacle provided there is a sand supply present and the velocity is high enough. This is the case on Earthand the numerous dune fields inside craters on Mars show the same applies there. This does not mean that the dunes are younger than the landslide, they might be older, but simply that the fetch argument does not make sense.

The fact that this is a more complex example of the convex/concave illusion than the those cited by our worthy host does not make the illusion it any less valid. The fact that the appearence of convexity is only seen by 1) some, 2) when the image is at certain orientations, 3) disappears at higher magnifications shows that it is an illusion.

The examples you provide of other transverse dunes in other valleys reinforces my point that there is no need to seek other explanations for these features.

I don't know of any MOC steroimagery of this area. If there is, I would appreciate the link, it would do just as well. My not mentioning it was not to imply there was anything of it, although my understanding is that the purpose built stereo cameras on Mars Express is a better instrument for this purpose, just as MOC is better for others.

Let me reverse your question to in the earlier email: what you would require as legitimate evidence that these are dunes?

Jon

There's a lot of tap dancing going on to explain why the objects in question are 'tubes'. The problem is one would have to think either NASA is covering up again :wink: or the astronomers are wrong for whatever long and complicated reasons Tripp can see that they can't.

Personally, they look exactly like dunes on a canyon floor to me, especially the 3D pic.

But even if they looked like tubes, it's silly to think the planetary geologists at NASA didn't know what they were looking at. Gimme a break. If NASA scientists couldn't interpret 2D and 3D images from orbiting satellites then how did they get their jobs, their degrees, their reputations?

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