The Torino Scale uses a scale from 0 to 10. Where 0 indicates an object has a negligibly small chance of collision with the Earth or is too small to penetrate the Earth's atmosphere intact. A 10 indicates that a collision is certain, and the impacting object is so large that it is capable of precipitating a global disaster. There are no fractional values or decimal values used.
An object is assigned a 0 to 10 value based on its collision probability and its kinetic energy (expressed in megatons).
The Torino Scale also uses a color code from white to yellow to orange to red. Each color code has an overall meaning:
- White - "Events having no practical consequences". Category 0.
- Green - "Events meriting careful monitoring". Category 0 - 1.
- Yellow - "Events meriting concern". Corresponds to categories 2 - 4.
- Orange - "Threatening events". Corresponds to categories 5 - 7.
- Red - "Certain catastrophic collisions". Corresponds to categories 8 - 10.
The Torino Scale was created by Professor Richard P. Binzel and named after a conference in Torino, Italy (Turin).
See also Palermo Technical Impact Hazard Scale