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Risk scale

The Palermo Scale

A more technical, logarithmic scale used by specialists to rank impact hazards against the background risk of a random impact of the same size over the same time. Values below zero mean a threat less than the everyday background; above zero warrants attention.

Knowledge connections

Sources

The primary and reference sources this topic draws on.

  • NASANational Aeronautics and Space Administration

    Mission data, planetary science, space telescopes, and public-domain imagery.

    Most NASA-produced imagery is in the public domain; individual items are checked for usage terms before publication.