Opportunity Rover's image analysis: Microbialites on Mars?

Abstract

The Mars Exploration Rover Opportunity investigated plains at Meridiani Planum, where laminated sedimentary rocks are present. The Opportunity rover's Athena morphological investigation showed microstructures organized in intertwined filaments of microspherules: a texture we have also found on samples of terrestrial (biogenic) stromatolites and other microbialites. We performed a quantitative image analysis to compare images (n=45) of microbialites with the images (n=30) photographed by the rover (corresponding, approximately, to 25,000/15,000 microstructures). Contours were extracted and morphometric indexes were obtained: geometric and algorithmic complexities, entropy, tortuosity, minimum and maximum diameters. Terrestrial and Martian textures present a multifractal aspect. Mean values and confidence intervals from the Martian images overlapped perfectly with those from the terrestrial samples. The probability of this occurring by chance is 1/2 8 , less than p<0.004. Terrestrial abiogenic pseudostromatolites showed a simple fractal structure and different morphometric values from those of the terrestrial biogenic stromatolite images or Martian images with a less ordered texture (p<0.001). Our work shows the presumptive evidence of microbialites in the Martian outcroppings: i.e., the presence of unicellular life on the ancient Mars.

Microbialites at Gusev Crater, Mars.

“…We may note that at Spirit location we obtained the same results we have had analyzing sediments photographed by Opportunity Rover at Meridiani Planum [21], a region very far away from Gusev crater. On February 2015, Nora Nofke [44], in a visual inspection of images shot Note the remarkable similarity of the Earth/Mars indexes: The probability of this occurring by chance is less than p<0.004.…”

“…Abiogenic pseudostromatolites, as well other abiogenic minerals, reveal always a simple fractal (and not multifractal) textures (Figure 7) [20,21]. The morphometric analysis also shows that the Martian and terrestrial textures were extremely similar to each other; the average values and confidence intervals of the eight independent morphometric parameters of the terrestrial and Martian images perfectly overlapped with each other (table 1).…”

“…Recently, we performed a fractal morphometric quantitative analysis of the Martian outcroppings explored by the Rover Opportunity revealing evidences of the presence of microbialites at Meridiani Planum [21]. In order to search for possible signature of microbialites in other Martian regions, we have performed a morphometric analysis of the Martian outcroppings shot by the Athena facility aboard of the Rover Spirit, comparing fractal morphometric indexes of the microtextures evidenced in the Martian outcropping with the ones of terrestrial microbialites.…”

Searching for Life on Mars: the Role of Chaos

“…A fractal analysis was performed evaluating the terrestrial and the Martian images: geometric complexities at low and high scales, information dimensions (entropy) at low and high scales, algorithmic complexity (Lempel-Ziv index or "randomness"), fractal dimension of the minimum path (or "tortuosity"), maximum diameter, minimum diameter. The fractal analysis of the Athena images shot by the Opportunity rover, analyzing 15,000 microstructures, showed fractal parameters that were overlapping the ones of terrestrial biogenic microbialites: the probability of this occurring by chance was less than 1/2 8 , p<0.004 (Table 2) (while, abiogenic pseudostromatolites presented morphometric indexes statistically different from the ones of biogenic stromatolites) (Bianciardi et al 2014). Analogous results were obtained analyzing 20,000 microstructures shot by the Spirit rover (Bianciardi et.…”

Life on Mars: time to start

“…But we have a huge amount of data, chemical and morphological, that we have received from a large number of probes sent to the Red Planet in the past 20 years. In that way, the writer was able to reanalyze the signals from the Viking Labeled Release Experiments in order to search for chaotic bio-indexes [9], or to search for morphological-morfometric biosignatures in the Athena images obtained by Opportunity rover [10] or Spirit rover (this issue). I'm sure a lot of information is still hidden within pictures or chemical analysis provided by the probes.…”