Image Courtesy of NASA
Experiments on the International Space Station (ISS) have been recently conducted with bacteria, blue-green algae, plant seeds, fungus, lichens and little animals called Tardigrades. These were all part of an experiment designed by the European Space Agency called EXPOSE. This experiment exposed all these life forms on a platform outside the space station for 18 months and were then returned to Earth to see if they could survive their trip and reproduce.
The bacteria Bacillus subtilis forms tough outer shells when exposed to inhabitable conditions and while survivors on the outer layer of bacteria were rare, those bacteria underneath were partially protected from the Sun's UV rays and approximately 50% survived. This means that these bacteria could in fact, survive a trip through space.
Two forms of Black Fungi were also exposed on the platform of the ISS for the same 18 month period. Upon their return to Earth it was noted that 60% of the fungi survived, with membranes in-tact and DNA stable. However only 2-9% of the fungi exposed to space actually reproduced to form colonies. Regardless of the low percentages, the experiment showed that Fungi can also survive space.
Seeds from the tobacco plant and a relative of the mustard plant were also exposed for 18 months in the same ISS experiment. Approximately 23% of the seeds exposed, actually sprouted on Earth afterwards. Therefore these seeds proved they can withstand the rigours of space and still survive/reproduce.
Several Lichens were also along for the 18 month ride on the ISS, exposed to the harsh space conditions. Approximately 71% of the plant cells and 84% of the fungal cells showed life after exposure to space and approximately 50% of the cells were able to start photosynthesis once again.
Finally, little animals called Tardigrades, known to go completely dormant under extreme conditions on Earth were also exposed in the same experiment. They survived 10 days when completely exposed. When partially protected from the Sun's most harmful UV rays, these tough little critters survived and 68% were revived after rehydrating on Earth. Not many ultimately survived and the survivors laid fewer eggs than their Earth counterparts but the eggs of these survivors did hatch healthy tardigrades.
All these experiments demonstrate that various forms of life can survive the harsh conditions of space if partly protected within a meteorite or comet. This suggests that origins of life on Earth could have been transported via meteorites.
Maddalena Environmental Inc.