Torino scale

The Torino Scale is a method for categorizing the impact hazard associated with asteroids and comets. It is intended as a tool for astronomers and the public to assess the seriousness of predictions.

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 (proportional to mass times velocity squared).

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 (Turin), Italy.