The theory of Panspermia suggests that life was brought to Earth from an external source in space. The theory can be further divided into a) Neopanspermia, the view that life continues to arrive from space to Earth, b) Pathospermia, the idea that pathogenic organisms arrive from space and c) Cometary Panspermia which specifies that extraterrestrial organisms originate from comets. This main aim of this study was providing evidence in support of Neopanspermia. Six stratospheric balloon launches were carried out in order to sample the stratosphere for microbial cells (biological entities, BE). Analysis of isolates was achieved using Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDAX), and Molecular techniques, to help determine the biological nature of any isolates and their origin. SEM and EDAX showed that, while most of the isolated material was inorganic cosmic dust, a few were biological in nature, although generally not recognizable as known terrestrial organisms. Some of the BEs were larger than the theoretical 5 micron limit for the transfer of a particle from Earth to the sampling heights, thereby suggesting a non- terrestrial origin. This was confirmed by the lack of similar sized (i.e. exceeding 5 micron) known terrestrial organisms such as pollen, grass shards, and fungal spores. There is clearly no sieve present in the atmosphere that would allow the isolated BEs to be elevated to the stratosphere from Earth while holding back known biological forms. It was therefore concluded that the large biological entities we isolated from the stratosphere are incoming to Earth from space and continually impact the Earth. Single cell amplification and identification also showed the presence of DNA and revealed a diverse population of known microorganisms distinct from the isolated biological entities. The ability of microbes to regain viability from ancient samples was also assessed by the isolation of bacteria from amber and halite rocks, thereby providing evidence that these organisms can survive after an extended period of millions of years, a finding which is of potential relevance to the transfer of microbes in the process of panspermia. Three meteorite types were also examined for biosignatures using SEM and EDAX techniques, two showed microfossil formations which can provide evidence for the theory of cometary panspermia. Evaluation of microbial survivability in the presence of exposure to ultraviolet C when embedded in ice was evaluated, as was the potential shielding by the presence of solid inorganic particles. It was also demonstrated, that the use of visible light generated by UV from fluorescence can provide energy for Cyanobacteria, which might have been the first microbes to inhabit our planet. Showing that life can survive in such conditions without the need of a protective atmosphere made up of oxygen that is necessary to form the protective ozone layer, this may explain how the first microbes were introduced to earth in the panspermia theory.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:723211 |
| Date | January 2017 |
| Creators | Omairi, Tareq |
| Contributors | Wainwright, Milton |
| Publisher | University of Sheffield |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://etheses.whiterose.ac.uk/18292/ |
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