The Torino Scale

The Torino Scale, created by Professor Richard P. Binzel in the Department of Earth, Atmospheric, and Planetary Sciences at the Massachusetts Institute of Technology, is a color coded and numbered scale ranking the threats to Earth from asteroids and comets.

When a new asteroid or comet is discovered, initial predictions for where the object will be months or decades in the future are rough estimates, and subject to changes based on collecting additional data.

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.