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Asteroid-Comet Destruction Scale
The Info Service Chart & Reference Guide
| Scale | Potential |
| 0 | The likelihood of a collision is zero, or well below the chance that a random object of the same size will strike the earth within the next few decades. This designation also applies to any small object to reach the earth's surface intact. |
| 1 | The chance of collision is extremely unlikely, about the same as a random object of the same size striking the earth within the next few decades. |
| 2 | A somewhat close, but not unusual, encounter. Collision is very unlikely. |
| 3 | A close encounter, with 1% or greater chance of a collision capable of causing localized destruction. |
| 4 | A close encounter, with 1% or greater chance of a collision capable of causing regional destruction. |
| 5 | A close encounter, with a significant threat of a collision capable of causing regional devastation. |
| 6 | A close encounter, with a significant threat of a collision capable of causing global catastrophe. |
| 7 | A close encounter, with an extremely significant threat of a collision capable of causing global catastrophe. |
| 8 | A collision capable of causing localized destruction. Such events occur somewhere on earth between once per 50 years and once per 1,000 years. |
| 9 | A collision capable of causing regional destruction. Such events occur between once per 1,000 years and once per 100,000 years. |
| 10 | A collision capable of causing a global climatic catastrophe. Such events occur between once per 100,000 years or less often. |