Could Icy Moons Of Europa And Callisto Sustain Lif Essay, Research Paper

Could icy moons of giant planets, such as Europa and Callisto, provide possible habitable environments for living organisms? Until such task is actually accomplished, scientists and researchers all over our world will forever be trying to find life in other parts of both our galaxy, and the Universe. Such fascination with extraterrestrial life has been brought to somewhat of a peak with the recent findings on two of Jupiter s so-called Galilean Satellites : Europa and Callisto. The findings from NASA s Galileo spacecraft indicate that both moons may have an ocean locked beneath their icy surfaces. (Charles Petit 1998) With recent discoveries in the McMurdo Dry Valleys of Antarctica, there is some speculation as to the possibility of living organisms, microbes in particular, on one if not both of these jovian moons. Living organisms typically require optimal conditions for growth and development. In the case of microbes, however, these optimal conditions are far from the ones needed for mammalian life to exist. Therefore, a habitable environment does not necessarily imply the possibility of human life. In this respect, the possible oceans on both Europa and Callisto could provide, or already may be providing, a living environment for microbes (i.e. cyanobacteria). On Europa, through the use of infrared spectrometry, whole landscapes paved with hydrated salts have been found, in contrast to many others which consist of nearly pure ice. (Jeffrey S. Kargel 1998) This discovery could possibly indicate that Europa s surface has an origin in a salty ocean. If this were the case, then it could also be possible that Europa s ocean once harbored many different species of microbes. In addition, very recent research has indicated that Callisto may also have an ocean buried under a thick sheet of ice. The discovery was made when the ocean betrayed itself through wiggles in Jupiter s magnetic field . (Charles Petit 1998) According to these findings, it is more than likely that a salty, electrically conductive ocean lies under the moon s surface, since Callisto s atmosphere does not have enough charged particles to generate the magnetic field detected by NASA s Galileo spacecraft. However, the thick sheet of ice (around 100 miles thick) covering the ocean makes the possibility of life on Callisto very slim. (Krishan Khurana in Petit 1998) The only terrestrial evidence scientists and researchers have that life can exist on ice is one of the harshest places on Earth: the McMurdo Dry Valleys of Antarctica. The temperature never climbs more than 4 degrees above freezing. Yet in this frigid desert, biologists have found a remarkable community of microbes clumped into temporary pockets of water several feet beneath the surface. Researchers believe that these organisms, which survive where no one had expected to find any living things, provide a model for what life might be like on other worlds. (Kathy A. Svitil 1998) With concrete evidence that living organisms can survive in an icy-aquatic environment such as the one in Antarctica, then it is logical to assume that the same situation could allow living organisms to survive on other worlds, such as Europa or Callisto. In fact, according to UCLA space physicist Margaret Kivelson: Some 90 miles below Callisto s surface, radioactive heat from rocks and tremendous pressure might create temperatures approaching the melting point of water. (Kivelson in Discover 1998) With conflicting prospects for the possibility of life on Callisto, it is hard to make a definitive statement one way or the other as to the likelihood of Callisto having a habitable region for living organisms. Nevertheless, there is substantial evidence pointing to the distinct possibility of life and the possibility that Callisto s icy ocean could one day melt enough to provide a favorable environment for microbes, such as in the McMurdo Dry Valleys of Antarctica.

In reviewing all the research presented on the composition of two of Jupiter s jovian moons, or two of the so-called Galilean satellites , it is clear that either of the two or maybe even both could provide possible habitable environments for living organisms. The controversy lies in the existence of a salty ocean on both Europa and Callisto, and whether these oceans could support life if they weren t so heavily covered in slush and ice. Once proof of an ocean is concrete, and proof of radioactive heat from rocks and sufficient pressure is also evident (to raise the ocean temperature), then it would be safe to say that living organisms could find a niche on these moons (just like the microbes living on ice in the McMurdo Dry Valleys); and obviously with such landmark discoveries on simply two of Jupiter s sixteen moons, further research could show that many other worlds in our galaxy alone could harbor some shape, size or form of life. BIBLIOGRAPHY Anderson, J.D. Distribution of Rock, Metals, and Ices in Callisto. Science vol.280 June, 5 1998: 1573-1576 Kargel, Jeffrey S. The Salt of Europa. Science vol.280 May 22, 1998: 1211-1212 McInnis, Doug. Wanted: life-bearing planets. Astronomy vol.26 no.4 April, 1998: 38-44 Petit, Charles. Callisto s icy secret. U.S. News and World Report. November 2, 1998: 55 Svitil, Kathy A. Life on Ice. Discover. October 1998: 38 Talcott, Richard. Jumping Jupiter: the Galileo spacecraft has sharpened our view of the solar system s largest planet and its four largest moons (Io, Callisto, Europa, Ganymede) Astronomy. Vol.26, no.6 June, 1998: 40-46 Unknown. Other worlds, other oceans. Discover. vol.19, no.9 September

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