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floppy_lobster
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I am a scumbag ex car salesman. Did you pay too much?
Dec 2004
time: 05:16
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Taken from Metaresearch
(1) The white bands. Pieri is really trying to explain only the white bands, not the glassy tubes, as dunes. We see these in many places -- there must be thousands of examples by now. SPSR geologists ruled out dunes early-on as a viable explanation because of considerations such as these:
(a) "Winds" on Mars are insufficient to build large dunes. The surface atmosphere on Mars is roughly 1% that on Earth, and Earth's is in turn only about 1% that on Venus. The atmosphere on Venus is so thick that a 7-mph wind has hurricane force. Analogously, winds on Mars would have to reach hurricane speeds to be felt as the gentlest of breezes. They would require substantially greater speeds to develop enough lift to perform large dune-building on otherwise flat terrain. Jet-stream speeds might arise at higher altitudes, as they do on Earth; but are least likely at the surface.
(b) Below-surface winds require channeling. The white bands are often seen in cracks and fissures. These ought to be sheltered from surface winds. The exception would be a case where a canyon had a wide mouth at one end that could collect a large volume of wind and channel it into a much narrower canyon. However, the cracks and fissures containing white bands are not of that character.
(c) The white bands are perpendicular to adjacent features. Where the white bands are seen on the surface of Mars (the "crenulations"; e.g., Fig. A), they often align perpendicular to adjacent surface features. It is easy so see how sand might be blown up against a surface feature and pile up there, but such piles would be elongated along the surface feature. The surface feature might perform a one-sided channeling of the winds, but that is inconsistent with individual white bands showing no width, height, or spacing variation with distance from the surface feature.
(d) The white bands have appreciably higher albedo than the surface material around them. Dunes ought to be made of the same material as the nearby surface, but wind-blown and deposited in wave-like patterns. However, the same material should cover all nearby terrain. But the actual white bands are sharply brighter than the material between them, and in some cases brighter than anything on the surrounding terrain.
(2) The glassy tubes. In a few places where the surface is cracked or where erosion has exposed what was previously buried, we see the white bands as markings on, or bands around, glassy tube-like structures (e.g., Fig. B). The "dunes" hypothesis does not explain these features.
(a) The glassy tubes have distinct outlines. Nothing about the "dunes" hypothesis requires that the extremities of the dunes be connected by an outline, yet the "flat view" interpretation of the glassy tubes is that they are outlines paralleling or connecting the extremities of the dunes.
(b) The glassy tubes appear to be translucent. In many places, one sees portions of faint white bands between the bright ones, as if seeing through translucent tubing. In isolated places, one sees complex structure faintly between white bands.
(c) A glassy tube appears to produce a specular reflection of sunlight. In one case, a roundish spot of saturated white light appears on a glassy tube . It is positioned on the side toward the Sun, and is positioned such that a specular reflection of the Sun is a possible explanation. As a singular, very bright spot near the end of a section of glassy tubing, no other obvious explanation suggests itself, and any invented for the purpose would be ad hoc. Because natural terrain scatters sunlight, if this spot is reflected sunlight, that would be consistent with tubules of a glassy or plastic-like quality.
(d) The glassy tubes cast shadows. Where shadows can be seen, they are consistent with the glassy tube interpretation, but not always with the "dunes" interpretation. In some cases, such as the glassy tubes on the "Cliff" at Cydonia, the shadows are clearly cast by tube-like features. The shadows are beside the tubes on the side opposite the Sun, parallel the tubes, and narrow when the tubes narrow. No "dunes" or other alternate interpretation to the tubes is available for such cases.
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Boris Godunov
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Portland, OR
Aug 2001
time: 00:16
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http://www.madsci.org/posts/archive...79553.As.r.html
But here is where one of our main difficulties arises. When we get these fantastic and amazing images back from Mars, we have to always remember that we are looking at Mars and not the Earth. As humans, we are used to how things work on Earth and so we tend to look at other planets with "Earth Goggles" on. We want to try and interpret other planets by how they look compared to Earth, and while it may be useful at some times, we can run into huge problems when we try to do this. The first thing we need to do is take off our "Earth Goggles" and remember that we are looking at the planet Mars, which is very different from Earth.
The surface of Mars behaves differently than the surface of Earth because of these differences between the planets. Earth has a huge atmosphere, with lots of liquid and gaseous water. Mars is a desert planet – it is dry, has a thin atmosphere with lots of huge dust storms and, because of the temperatures and pressures at the surface of the planet, water cannot exist as a liquid at its surface. It is important to remember these differences when we look at the "glass tubes on Mars" that are in the MOC (Mars Orbiting Camera) image that you referenced (MOC narrow-angle image M04-00291). We also need to remember that this is Mars and not Earth when we try to interpret the images, and when we read articles by people who are trying to interpret these images.
The features on Mars that look like "glass tubes" in the MOC images do have an official interpretation. These "glass tubes" are not tubes at all. In fact, they are depressions in the surrounding surface caused by either ancient river valleys that have since dried up or surface faulting. Scientists might refer to these depressions as valleys or troughs. The bright linear features that cross these valleys are sand dunes made up of material that is transported by strong winds on Mars to these valleys. This interpretation is agreed upon not only by the people who built and operate the MOC camera (Malin Space Science Systems), but also NASA, as well as the overwhelming majority of professional planetary scientists who are interpreting these images. (I showed these images to a number of planetary geologists and asked them how they would interpret these features. Every single scientist said they were sand dunes inside of valleys, without hesitation. This is mainly because we are used to looking at such images on Mars and seeing the different forms that sand dunes can take. We have been trained to take off our "Earth Goggles when we see an image from another planet. I encourage you to check out Malin Space Science Systems main page (link below). They have a huge searchable image collection (link below) of not only sand dunes on Mars, but all sorts of other features as well, like impact craters and ancient river valleys.)
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21-12-2004 08:43
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