Palermo Technical Impact Hazard Scale The Palermo Technical Impact Hazard Scale is a logarithmic scale used by astronomers to rate the potential hazard of impact of a near-earth object. It combines two types of data--probability of impact , and estimated kinetic yield--into a single "hazard" value. A rating of 0 means the hazard is as likely as the background hazard (defined as the average risk posed by objects of the same size or larger over the years until the date of the potential impact). A rating of +2 would indicate the hazard is 100 times more likely than a random background event. A similar but less complex scale is the Torino scale, which is used for simpler descriptions in the non-scientific media. The Palermo Scale value, P, is defined as the base 10 logarithm of the ratio of the impact probability pi to the background impact probability over the time T to the event: $P\; =\; \backslash log\_\; \backslash frac$ The annual background impact frequency is defined for this purpose as: $f\_B\; =\; 0.03\; E^$ where the energy threshold E is measured in megatons. The near-Earth object (89959) 2002 NT7 was the first near-Earth object detected by NASA's latest NEO programme to be given a positive rating on the scale of 0.06, indicating a higher than background threat. The value was subsequently lowered to -0.25 after more measurements were taken. However, asteroid (29075) 1950 DA holds the record for Palermo scale values, with a value of 0.17 for a possible collision in the year 2880. The 0.17 value indicates that a collision with this object is considered to be 48% more likely than a random background event: perhaps six in a thousand compared to four. See also Torino scale, Near-Earth object External links NASA NEO Programme http://neo.jpl.nasa.gov/index.html Description of the scale http://neo.jpl.nasa.gov/risk/doc/palermo.html (89959) 2002 NT7 is the first object discovered with a positive measurement on the Palermo scale Most Popular Articles: Music    Musical Instruments    Guitar    Classical Music    History    Music Definition    Country Music    Rock Music    Pop Music    Hip Hop    Rap    DJ    Video Games    Casino Games    Poker    Blackjack    Casinos    Real Estate    Loan    Auction    eBay    Marketing    Search Engine Optimization    File Sharing    MP3    Music Industry    Kazaa    Internet    Supermodel    Fashion    Fashion Designers    Erotica    Modeling    Clothing    Boots    Shoes    Diamond Engagement Rings    Diamond    Rugs    Gospel Music    Affiliate    E-Commerce    Radio This article is licensed under the GNU Free Documentation License at http://www.gnu.org/copyleft/fdl.html You may copy and modify it as long as the entire work (including additions) remains under this license. You must provide a link to http://www.gnu.org/copyleft/fdl.html To view or edit this article at Wikipedia go to http://www.wikipedia.org/wiki/Palermo_Technical_Impact_Hazard_Scale