Searching Life on Mars: the role of Chaos.

Searching Life on Mars: the role of Chaos. Giorgio Bianciardi, DSMCN, Siena University, Viale Bracci, Siena, Italy. giorgio.bianciardi@unisi.it In the last decades, concepts of self-organization, transitions, multiplicity of states and complexity have become very important in biology, concepts arisen from the physics of Chaos. That new model of living system, proved by the presence of chaotic behaviour and fractal structures in live beings, offer us approaches to identify new markers in the field of astrobiology. We have reanalyzed the CO2 levels released by the Martian regolith after addition of amino acids and carbohydrates in the Labeled Release experiment performed by Viking 1 and Viking 2 Martian probes in order to search for chaotic bio-indexes (Bianciardi, Miller, Straat, Levin, 2012). Complexity data (Lempel-Ziv index, Hurst and Lyapunov exponents, BDS statistic and Correlation time) of Martian LR active response were deeply superimposable with terrestrial biological time series (p<0.0001). In effect, in a cluster analysis LR gas evolution in the active experiments sorted with terrestrial biological measures, while controls sorted with non-biological measures, providing support for the conclusion that the Viking LR experiments detect extant microbial life on Mars. Fractal geometrical indexes, applied to Mars Rover imagery showed intriguing similarities in the morphometric fractal indexes collected in the ancient sedimentary rocks on Mars and structures shaped by microbes on Earth. We conducted a quantitative, objective, image fractal analysis of sedimentary microstructures photographed by the Mars Opportunity and Spirit rovers comparing with terrestrial microbialites/stromatolites (rocks built by cyanobacteria), in order to evaluate the textural complexity (fractal dimension and entropy at high and low scales, Lempel-Ziv index, tortuosity and diameters) of the microstructures present in the samples (Bianciardi, Rizzo, Cantasano, 2014 & 2015). Both textures, from microbialites (Earth) and from the selected images taken by rovers (Mars), presented a multifractal aspect and all the Martian and terrestrial textures resulted extremely similar to each other, with high statistical significance (p<0.001) (successively, other Investigators have reached similar conclusions at an observational level, Noffke, 2015, Ruffi & Farmer, 2016). Now, we are performing a fractal analysis of structures present in the images snapped by the Martian rovers claimed to be very similar to terrestrial lichens and fungi (Dass 2017; Joseph 2014; Rabb 2018; Small 2015). Results clearly indicate the evidence of a biologic origin of those Martian structures. The chaotic/fractal approaches performed by us support recently evidences by other Authors of the presence of life on Mars, in the past and in the present time (for a Review, see: Joseph, Dass, Rizzo, Cantasano, Bianciardi, 2019). Bianciardi, G., Miller, J. D., Straat, P.N., Levin, G. V. (2012). Complexity Analysis of the Viking Labeled Release Experiments, Internationa Journal of Aeronautical and Space Sciences, 13(1), 14–26. Bianciardi, G., Rizzo, V., Cantasano, N. (2014). Opportunity Rover’s image analysis: Microbialites on Mars? Internationa Journal of Aeronautical and Space Sciences, 15(4), 419-433. Bianciardi, G., Rizzo, V., Farias, M. E., Cantasano, N. (2015). Microbialites at Gusev Craters, Mars. Astrobiology Outreach, 2,5. Noffke, N. (2015). Ancient Sedimentary Structures in the < 3.7b Ga Gillespie Lake Member, Mars, That Compare in macroscopic Morphology, Spatial associations, and Temporal Succession with Terrestrial Microbialites. Astrobiology 15(2),1-24. Ruffi, W. & Farmer, J.D. (2016). Silica deposits on Mars with features resemblinghot spring biosignatures at El Tatio in Chile. Nature Communications, 7, 13554, DOI: 10.1038/Ncomms13554 Joseph, G., Dass, R.S., Rizzo, V., Cantasano, N., Bianciardi, G. (2019) Evidence of Life on Mars?, Journal of Astrobiology & Space Science Reviews, 1, 40-48.