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If you choose to follow any links to the abstract and/or complete text of the item listed below, you will be leaving the Strategian Web site. If you wish to return to this page from the Web page you are sent to, please use the Back option of your browser. P. Brown, R.E. Spalding, D.O. Revelle, E. Tagliaferri, and S.P. Worden The Flux of Small Near-Earth Objects Colliding with the Earth. (... recently, there has been renewed concern about the likelihood of asteroids striking the Earth and the potential damage caused by those collisions. Most of this concern, however, has been centered around the possibility of large asteroids [with diameters of 50 meters or greater] striking the Earth, and current methods of observing and tracking asteroids from the surface of the Earth tend to find only the larger asteroids. The authors report that asteroids with diameters smaller than 50–100 meters that collide with the Earth usually do not hit the ground as a single body; rather, they detonate in the atmosphere. These small objects can still cause considerable damage, such as occurred near Tunguska, Siberia, in 1908. A Tunguska-class event—the energy of which we take to be equivalent to 10 megatons of TNT—was previously estimated to occur every 200–300 years, with the largest annual airburst calculated to be 20 kilotons [kton] TNT equivalent. Using information obtained over the past 8.5 years from satellites orbiting the Earth, the authors conclude that destructive events as occurred at Tunguska happen much more rarely; they estimate that the Earth is hit on average annually by an object with 5 kton equivalent energy, and that Tunguska-like events occur about once every 1,000 years. Other keywords and phrases -- bolide detonations, small bodies -- from the text of the article) Nature Volume 420, Number 6913 (November 21, 2002): 294-296. How to find the above journal, magazine, or other publication? See Step 3: Locate of the Information Strategy for details. Questions? Please let me know. |
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