21 February 2013, 18:10

NASA publishes first pictures of Martian ‘door knob’

NASA publishes first pictures of Martian ‘door knob’

A photograph taken by NASA’s Mars-rover ‘Curiosity’ last week caused a stir among the scientific elite. On an image published on NASA's official website, a shiny, metallic-looking artefact can be seen that bears a passing resemblance to a hood ornament or a door knob. While some were quick to say the object had come from an alien spacecraft, others rejected any idea that the ‘knob’ was manufactured, arguing instead that the ‘handle’ had been naturally formed by the effects of weathering. As scientists continued to debate the strange object's origins, the internet was alive with recollections of the famous ‘Martian girl’; a 40 cm female figure that was photographed by ‘Curiosity’s’ predecessor ‘Spirit’, more than 5 years ago.

The shiny ‘door knob-looking’ object, photographed by ‘Curiosity’ on January 30th, is only 35 pixels in size, given that ‘Curiosity’s’ camera resolution is 150 microns per pixel and the object is approximately 2 meters away, the metallic item is around half a centimetre high. Despite its small size, the object has recently had a huge impact on geologists all over the world.

To many it seemed that ‘Curiosity’ has stumbled upon evidence of an ancient Martian civilisation, however, according to Ronald Sletten, from the Mars Science Laboratory team at the University of Washington, all that's been discovered is a simple ‘ventifact’; a surface that has been wind-eroded by fine dust or sand particles hitting it over a great deal of time. In this sense, the object, though ‘knob’ shaped, is of a completely natural origin. Sletten explained that the ‘handle’ is actually “a part of the rock that is different, harder and more resistant to erosion than the the rock in which it is embedded. On Earth, as on Mars, you can often see knobs or projections from surfaces eroded by the wind, particularly when a harder, less erodible rock is on top. The rock on top of the projection is likely to be more resistant to wind erosion and protects the underlying rock from being eroded.”, Sletten went on to explain; “the shiny surface suggests that this rock has a fine grain and is relatively hard. Hard, fine grained rocks can be polished by the wind to form very smooth surfaces. It also may be shiny because it is wind-blasted and therefore dust-free, while the surfaces not directly being eroded by wind may have a fine layer of reddish dust or rock-weathering rind. The sandblasted surfaces may reveal the inherent rock colour and texture.”

One of the main criticisms of NASA's theory is that such a degree of erosion would require not only wind but water, which would only be possible if the planet had an atmosphere. Given that Mars did have such an environment several billion years ago, it is odd that that the tiny object was not weathered down completely. What is more, had this been a usual ‘ventifact’, as Sletten contends, ‘Curiosity’ would stumble upon such ‘subjects of natural erosion’ much more often. Another question hanging over NASA’s official explanation for the ‘door knob’ is that ‘ventifacts’ are usually formed from rock but not metal. Furthermore, none of the examples of Earthly ‘ventifacts’ shown in the agency's brochure have such an unusual shape; none of them are as thin and protruding. It's thought then that the object in ‘Curiosity’s’ photographs is almost too delicate and detailed to be a ‘ventifact’.

More generally, there is widespread disappointment with the quality of NASA’s explanation and the fact that the ‘door knob’ case was so rapidly closed. While Sletten’s is a good theory, ‘Curiosity’ followers on Twitter express their unease with the reluctance of NASA scientists to study the unusual artefact further. Internet observers want the Mars rover to return to the site where the controversial image was taken to drill into the object, or at the very least to take another photograph. Curiosity is very well equipped for this as it carries 10 different scientific instruments including 17 cameras and a rock-boring drill, all of which were specifically constructed to aid the rover in its quest to explore the ‘Red Planet’. Several days ago ‘Curiosity’ used its drill to collect samples by boring 2.5 inches into the surface, something that had never been done before.

Admittedly, nothing that Curiosity does on Mars is free; any decision to investigate the ‘handle’ would come at a cost; possibly requiring another scientific study to be sacrificed. However, looking through ‘Curiosity’ archives, it seems the ‘knob’, that might have been made by a long-extinct Martian civilisation, is one of the most intriguing discoveries that the Mars-rover has made to date and is therefore one worth studying in more depth. Moreover, given that ‘Curiosity's’ stated primary goal is geological research, the study of an unknown metallic object should fit squarely into that research category. The current explanation provided by NASA for the ‘ventifact's’ origins says nothing of its molecular composition and further research might shed light on what juxtaposition of elements or minerals might constitute the ‘handle’.

In the meantime, one can only hope that ‘Curiosity’s’ discovery will not be dismissed in the same way as ‘Spirit’s’ ‘Martian Girl’, a 40 cm female figure discovered on November 6, 2007 in Gusev’s crater that was quickly written off as a natural rock formation resulting from erosion. Several weeks after ‘Spirit’s’ discovery, NASA decided to discontinue study of the figure despite the anomaly having a distinct human form complete with gender differentiation. Back then, the President of the Mars Anomaly Research Society thought that this enigmatic form looked like the fossilised remains of a Martian woman fleeing a disaster such as a flood or volcanic eruption, or possibly a monument sculpted in memory of a similarly apocalyptic event. In the absence of definitive answers, debate around the ‘Martian girl’ continues.

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