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Aliens Don’t ExistAdvanced civilizations would have the means and motive to colonize – they should be here by nowGonzalez ’98 (Guillermo, Astronomer at University of Washington , Society, “Extraterrestrials: A modern view”, July/August, Volume 35, Issue 5, Proquest) Basically, there are two ways of approaching the ETI question (as in almost any field of study): empirically and theoretically. The empirical approach is encapsulated most succinctly in Enrico Fermi's famous question, "Where are they?" Newman and Sagan in 1979 attempted to answer Fermi's question by claiming that there has not been sufficient time for a spacefaring civilization to colonize the Milky Way. They based this on a simple model of galactic colonization not unlike those used to describe the colonization of the Pacific islands (except that galactic colonization will be a less random process). In 1981 Frank Tipler of Tulane University pointed out several problems with Newman and Sagan's analysis and claimed that the true colonization time scale is much less than the age of the Milky Way. He quoted a time scale of no more than 300 million years. More recently, Ian Crawford in a 1997 paper in Astronomy and Geophysics quoted values of 5 to 50 million years for the colonization time scale, similar to other recent estimates. One might object that the resources required for undertaking a galactic scale colonization (or exploration) are astronomically huge! Again, Frank Tipler provided an answer to this objection. He argued very cleverly that a technological civilization, once it develops the ability to send a probe with a Von Neumann machine to a neighboring planetary system, can colonize the Milky Way fairly easily. A Von Neumann machine builds copies of itself using available raw materials and carries out specified tasks. Human beings are natural versions of the Von Neumann machine concept. The first proto-Von Neumann machine may have already been built; the 26 September 1997 issue of Science reported the construction of the first tiny "self-repairing, self-replicating version of a specialized computer." Certainly, the still fledgling field of molecular nanotechnology bears close watching (NASA has already expressed interest). The Mars Pathfinder might also be considered as a tiny (but significant) baby step towards the eventual construction of a Von Neumann machine in that it can perform complex operations without direct and immediate human guidance. The Von Neumann machine approach to colonization does not require very much investment in resources, since almost all of it is spent on the first probe. It need not be very large--just capable of building a Von Neumann machine that can assemble copies of itself and sending them off in interstellar ships. Subsequent probes will draw on the natural resources of the worlds they visit, and each newly explored system becomes the base from which new missions depart. In addition to returning valuable information about other planetary systems, Von Neumann probes can reduce the cost of eventual human colonization by preparing suitable planetary systems for habitation and sending back interstellar ships prepared for manned spaceflight--a sort of interstellar ferry system. The construction of the first interstellar probe (capable of building a Von Neumann machine) will likely be a spin-off of automated mining activities in the Solar System. Given the dangers of working in the space environment and the long-term isolation of workers from Earth (say, in the asteroid belt between Mars and Jupiter), the motivation to automate extraterrestrial mining will be great, very likely resulting in relatively minor development costs for the first Von Neumann machine. Hence, the criticism that an advanced civilization might lack the motivation to colonize other worlds is rendered unlikely, as interstellar travel is a relatively small step after off-world mining is achieved. Notice that a civilization need not maintain a long-term interest in interstellar travel; once the first probe is sent out, exploration and colonization is effectively automatic. Aliens Don’t ExistIf extraterrestrials existed they should be in the solar system – their absence proves their nonexistenceNew Scientist ’96 (Marcus Chown, “Is there anybody out there?”, November 23, L/N) One person who is convinced he has the answer is Frank Tipler of Tulane University in New Orleans. "If the Martian evidence holds up," he says, "we may have to face the fact that primitive life is common in the Universe but that the development of intelligence is vastly improbable." In fact, he believes it is so fantastically improbable that it has happened only once since the big bang. "I believe we are the very first intelligence to arise in our Galaxy," he says.Magazine This extraordinary claim is based on a straightforward comparison between the age of our Galaxy and how long it would take a civilisation capable of interstellar travel to explore and colonise it. According to Tipler, such a colonisation would be achieved most efficiently by dispatching self-reproducing probes to the stars. The concept of self-reproducing probes was developed back in the 1950s by John von Neumann, a Hungarian-American mathematician. On arrival at a star, the von Neumann probes would use the available resources to build and launch copies of themselves. "One probe would become two, two would become four, and so on," says Tipler. "In this way, they would proliferate exponentially." Of course, you could argue that if probes like these populated the Galaxy, that would be very different from finding life. However, Tipler makes no distinction between the putative extraterrestrials and their robot emissaries. The probes would need to be highly intelligent and capable of using the material and energy resources in their environment to reproduce. In a sense, they would be life forms in their own right, flesh made machine, and the space-faring successors of planet-based life.
Long overdue "The time needed to explore the Galaxy is hugely less than the age of the Galaxy, which is around 10 billion years," says Tipler. "So, if extraterrestrials exist, they should be here in the Solar System today. Since they're obviously not, they don't exist." Directory: files files -> Answer True False 2 points Question 2 files -> Integer programming and game theory files -> 4 Integer Programming files -> Bpa vehicle Window Repair Scenario #1 task: Procure vehicle window relacement. Objective files -> Pop Warner History files -> North Carolina Inclusion Initiative Mapping Where Children with ieps are Being Served Purpose files -> Fall 2013 Spring 2014 Program Data: Standard 1 Exhibit 4d files -> Hanban – asia society confucius classrooms network 2010 request for proposal files -> Northern England’s set-jetting locations Download 243.79 Kb. Share with your friends:
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