What is the Torino Impact Hazard Scale?”
The Torino Scale is a “Richter Scale” for categorizing the Earth impact hazard associated with newly discovered asteroids and comets. It is intended to serve as a communication tool for astronomers and the public to assess the seriousness of predictions of close encounters by asteroids and comets during the 21st century. When a new asteroid or comet is discovered, predictions for where the object will be months or decades in the future are naturally uncertain. These uncertainties arise because the discovery observations typically involve measurements over only a short orbital track and because all measurements have some limit in their precision. Fortunately, for the majority of objects, even the initial calculations are sufficient to show that they will not make any close passes by the Earth within the next century. However, for some objects, 21st century close approaches and possible collisions with the Earth cannot be completely ruled out. The Torino Scale utilizes numbers that range
The likelihood of a collision is zero, or is so low as to be effectively zero. Also applies to small objects such as meteors and bodies that burn up in the atmosphere as well as infrequent meteorite falls that rarely cause damage. A routine discovery in which a pass near the Earth is predicted that poses no unusual level of danger. Current calculations show the chance of collision is extremely unlikely with no cause for public attention or public concern. New telescopic observations very likely will lead to re-assignment to Level 0. A discovery, which may become routine with expanded searches, of an object making a somewhat close but not highly unusual pass near the Earth. While meriting attention by astronomers, there is no cause for public attention or public concern as an actual collision is very unlikely. New telescopic observations very likely will lead to re-assignment to Level 0. A close encounter, meriting attention by astronomers. Current calculations give a 1% or greater chan
There are five zones on the scale. No hazard, Normal, Meriting Attention, Threatening and Certain Collisions. They are color coded zones. The span is large: In the no hazard(white) zone, The likelihood of a collision is zero, or is so low as to be effectively zero. Also applies to small objects such as meteors and bodies that burn up in the atmosphere as well as infrequent meteorite falls that rarely cause damage. In the certain collision(red) zone, A collision is certain, capable of causing localized destruction for an impact over land or possibly a tsunami if close offshore. Such events occur on average between once per 50 years and once per several 1000 years.
