Asteroids Aff


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Potential impact of small asteroids is higher than ever–population density and urbanization

Lewis 1996 - professor of planetary science at the University of Arizona's Lunar and Planetary Laboratory (John S., Rain of Iron and Ice, p. 183-222)

Using our recent studies of comets and asteroids, it has become clear that average impact raters do not tell the whole story. Impact "storms" must occur (chapter 11). Most of the impactors strike the ocean (chapter 12), where some may deposit their own content of water and other ices, as on Mercury and Venus, or, in sufficiently large impacts, even blast off part of Earth's atmosphere into space. But all oceanic impacts throw up massive tidal waves that can devastate coastal regions without leaving any distinctive signature that says, "this was an impact event." Human casualties are possible from any event that drops kilogram-sized meteorites, and many such events have been reported (chapter 13), only to be dismissed by meteorite experts who demand absurdly high standards of proof. But clearly the real hazard lies with larger, rarer bodies. Even a modest aerial explosion like the fifteen-megaton Tunguska event would utterly devastate a modern city. The growth of global population in the last few centuries, the urbanization of human culture into glass boxes, and the vast increase in population along the seacoasts, all conspire to increase the risk from airbursts and tsunamis enormously. What are the likely events of the twenty-first century? What can we expect to occur in our lifetimes? This question can now be answered statistically by means of the process of computer simulation. All the available evidence on nearby bodies in space is folded into a statistical model of the size, composition and strength, abundance, and orbits of the near-Earth asteroid and comet population. All the evidence on the effects of giant explosions from studies of nuclear weapons tests, cratering, gas injection, airbursts, fire ignition, shock-wave chemistry, acid rain, and atmospheric erosion on Earth and other planets is included in statistical form. All presently understood hazards to life and property, insofar as we have discovered them, are also included. We can then run the model for a period of a century (a natural human time scale) to see what might happen. I have chosen the twentieth century as the setting for these runs because we know the population, population density, and technological abilities of Earth for that time period. The twentieth century provides a vehicle for more meaningful exploration of the influence such cosmic events would have had upon the world.



The plan solves asteroid collision

Ames Research Center 2003 - NASA’s Ames Research Center is a world-class research facility located in the heart of Silicon Valley. The center is involved with many high-tech projects, ranging from developing small spacecraft to managing some of the world’s largest supercomputers, and conducting astrobiology research (July 8, * Dr. Harrison H. Schmitt * Dr. Carolyn S. Shoemaker * David H. Levy * Dr. John Lewis * Dr. Neil D. Tyson * Dr. Freeman Dyson * Dr. Richard P. Hallion * Dr. Thomas D. Jones * Bruce Joel Rubin * Dr. Lucy Ann McFadden * Erik C. Jones * Marc Schlather * William E. Burrows, “ NASA NEO News: Open Letter to Congress on Near Earth Objects ” )

We recommend that Congress take the following measures to enhance the search for NEOs: * Increase search activities for detection of NEOs 0.62 miles (1 kilometer) in diameter and larger. Researchers estimate that only one-half of such NEOs have been located. The pace of identification should be accelerated. Support for Southern Hemisphere search activities may further increase the discovery rate and should be expanded. Even when NASA achieves its current goal of identifying 90% of large NEOs, the undiscovered remainder will, of course, still pose a potential hazard. Congress should direct NASA to pursue the search for all such objects to statistical completion. * Expand the search effort to include detection and tracking of NEOs smaller than 0.62 miles (1 kilometer). NEOs such as 2002 MN (about a hundred yards across) are not currently the target of any formal search program. Rather, they are discovered as by-products of the search for larger objects. Because an impact of even a relatively small NEO could still destroy a major city, the United States should establish the goal of predicting any close approach to Earth by any asteroid larger than 200 yards in diameter. * Increase funding for the Minor Planet Center (MPC) to $1 million annually. The MPC is responsible for the collection, computation and dissemination of the characteristics and orbits of asteroids and comets. As the central international clearinghouse for tracking NEOs, it should be funded at a level more commensurate with its important role in understanding and addressing the NEO threat. * Provide funding for more and better instrumentation and additional follow-up observations. In addition to maintaining existing optical and radar search programs, NASA should be given the added resources and mandate to enhance the instrumentation dedicated to NEO detection and to respond to NEO discoveries with more detailed observations. Such radar and spectroscopic observations are vital to refine asteroid orbits and determine an NEO�s general composition.
Increasing detection allows us to prevent a collision—NASA has the capacity but must do more

NAC 2010 (“Report of the NASA Advisory Council Ad Hoc Task Force on Planetary Defense,” Oct 6,

NASA has developed a strong foundation for understanding the NEO hazard and building a long-term capability to counter a potential asteroid impact threat. By taking the steps recommended in this report, the agency can expand this expertise and lead global efforts to develop an effective capability for Planetary Defense. Society now possesses sufficiently mature space technology to provide two of the three elements necessary to prevent future damaging asteroid impacts. NASA currently searches for the largest objects of concern and issues warning information for any asteroid discovered to approach Earth. New ground- and space-based search systems can increase our capability to provide impact warning for the smaller, more numerous asteroids. Although NASA has not demonstrated a specific asteroid deflection capability, the agency’s current spaceflight technology shows that impact prevention is possible. Actual NEO deflection demonstrations are being studied and are excellent candidates to be part of future NEO science and technology missions. The missing third element for NEO impact prevention is the international community’s readiness and determination to respond to a predicted future asteroid collision with Earth. NASA is well20 positioned to take a leading role in this government and international response, but to be ready, the agency must move well beyond search, analysis, and warning to develop the practical means for actually changing a threatening asteroid’s orbit. Without the ability to detect the most numerous asteroids, to alter NEO orbits, and to lead a global effort to plan a deflection campaign, the only possible U.S. response would be evacuation and disaster response. If NASA fails to prepare for Planetary Defense, and then a sizeable random NEO strikes Earth without warning, the damage to the U.S.’s leadership and reputation would swell the tally of the event’s devastating effects. NASA should begin work now on forging its warning, technology, and leadership capacities into a global example of how to effectively shield society from a future impact.

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