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S.F. meeting on extraterrestrial life
Search for extraterrestrial life moves to forefront
In S.F., space scientists agree on central theme for exploration David Perlman, Chronicle Science Editor Monday, December 15, 2003 -------------------------------------------------------------------------------- As NASA pursues unmanned missions throughout the solar system, the quest for signs of life on distant planets -- more likely in the past than in the present -- is gaining increased attention from space agency planners. The problems are formidable: They must increase their understanding of how life originated and evolved on Earth; they must deduce the most likely places where water could have existed on planets like Mars; and they must develop new techniques for drilling many yards, and later many miles, beneath the surface of such planets. Finally, the scientists must be scrupulously careful with every spacecraft and every tool that lands on any planet to make sure they do not carry microbes from Earth that would contaminate whatever extraterrestrial life might conceivably exist now or in the past. At last week's annual meeting of the American Geophysical Union in San Francisco, NASA-sponsored scientists from many research institutions called their search for life on other planets and their moons "a unifying theme'' for solar system exploration. "Astrobiology is now the intellectual centerpiece of NASA's efforts in space exploration," said Bruce M. Jakosky, professor of geology at the University of Colorado, referring to the new field that integrates astronomy with the study of life. Mars and Europa, the ice-covered moon of Jupiter, "appear as potentially habitable worlds, either today or in the past," he said. "And the smoggy atmosphere of Saturn's moon Titan may well cover a surface where intermittent water and organic chemicals might have encouraged the evolution of living organisms." As a result of recent discoveries of microbes living in freezing cold, with no oxygen or light, and the profound pressures of deep underground mines, Jakosky noted, the extreme diversity of life on Earth makes it quite likely that life could be or have been widespread in our solar system. "We could probably pick up some bugs right now on Earth that would find themselves quite happy in a Martian environment," he said. For 30 years, scientists scanning images of Mars from spacecraft have been tantalized by giant channels, broad basins and sinuous valleys on the Martian surface that look exactly as if water had flooded and flowed there billions of years ago. In coming weeks, three spacecrafts -- one stationary lander operated by the European Space Agency and two NASA rovers -- will set down on the Red Planet and search for signs of past and present life, and water. In an even more ambitious mission, astronomers and astrobiologists said at last week's AGU meeting that they have begun planning a voyage to Europa to study what must be deep oceans -- and possibly life -- beneath the icy crust of the Jovian moon. They envision sending a 300-foot-long, nuclear-powered craft -- called JIMO, for Jupiter Icy Moons Orbiter -- to spend five years circling Europa, plus two others, Callisto and Ganymede. Scientists have not ruled out landing probes or instruments on the surface of Europa to aid the search. The mission will fly no earlier than 2010 and could cost as much as $8 billion. As the space agency pursues missions to other planets, a major focus is protecting those worlds and ourselves, said John D. Rummel, who bears a unique title as NASA's "planetary protection officer'' in Washington. "As we discover life out there, we don't want to find that we've already killed it off." International space treaties require space-faring nations to develop foolproof techniques for rigorously sterilizing every object -- spacecraft or instrument -- that is designed to approach or land on a planet, he said. Similarly, when spacecraft are planned to return to Earth, they must be built so there is no possibility of unknowingly bringing an alien organism back to Earth. Back when the Apollo program was carrying astronauts to the moon, their samples of lunar rock were quarantined for months, and their instruments were sterilized. Because the job will be infinitely more difficult for the robotic planetary explorers, teams of scientists are already developing the crucial anti-contamination technology, Rummel said. NASA has created a major "Astrobiology Institute" with its headquarters at the Ames Research Center in Mountain View, with some 20 universities and research institutions participating. Geochemist David J. Des Marais, an astrobiology researcher at Ames, noted the importance of understanding the evolution of life on Earth if scientists are ever to understand how life might have developed on planets elsewhere. His own research into how life developed suggests that water must have first rained down on the new-forming Earth from comets and meteors as much as 4.9 billion years ago and that more massive impacts introduced organic chemicals within an additional billion years. "Proto-cells" then began to form on the warming Earth. And finally by 3.7 billion years ago, the first life appeared along the coasts of small, new continents in the form of "biofilms" and layers of microbial mats whose fossil forms have been discovered in recent years. Within a few hundred million years, those microbes had learned to use sunlight for energy, growth and reproduction. After a few million years, more advanced life forms emerged. And after that, the pace of evolution and growth of diversity increased swiftly, he noted. "Understanding the nature and timing of this ascent of life is crucial for discerning our own beginnings," Des Marais said. "This understanding also empowers our search for the origins, evolution and distribution of life elsewhere in our solar system and beyond." |
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"Steve Dufour" wrote in message "Proto-cells" then began to form on the warming Earth. And finally by 3.7 billion years ago, the first life appeared along the coasts of small, new continents in the form of "biofilms" and layers of microbial mats whose fossil forms have been discovered in recent years. Within a few hundred million years, those microbes had learned to use sunlight for energy, growth and reproduction. After a few million years, more advanced life forms emerged. And after that, the pace of evolution and growth of diversity increased swiftly, he noted. "Understanding the nature and timing of this ascent of life is crucial for discerning our own beginnings," Des Marais said. "This understanding also empowers our search for the origins, evolution and distribution of life elsewhere in our solar system and beyond." I read in the paper today they've discovered human dna in coral. Anyway it's all futile in the end - even if we don't destroy ourselves, or get destroyed, the sun will burn out & toast the earth..... Life is obviously teeming through the universe in various forms, but maybe the human version is one-off...? |
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"Whisper" wrote in message
... "Steve Dufour" wrote in message "Proto-cells" then began to form on the warming Earth. And finally by 3.7 billion years ago, the first life appeared along the coasts of small, new continents in the form of "biofilms" and layers of microbial mats whose fossil forms have been discovered in recent years. Within a few hundred million years, those microbes had learned to use sunlight for energy, growth and reproduction. After a few million years, more advanced life forms emerged. And after that, the pace of evolution and growth of diversity increased swiftly, he noted. "Understanding the nature and timing of this ascent of life is crucial for discerning our own beginnings," Des Marais said. "This understanding also empowers our search for the origins, evolution and distribution of life elsewhere in our solar system and beyond." I read in the paper today they've discovered human dna in coral. Anyway it's all futile in the end - even if we don't destroy ourselves, or get destroyed, the sun will burn out & toast the earth..... Life is obviously teeming through the universe in various forms, but maybe the human version is one-off...? Colossians 2:17 "... reality, however, is found in Christ." -sweet _________________________________ sweet 430 at hot mail dot com http://www.angelfire.com/ny5/jbc33/ |
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