by Rich Williams
I received a notice on the Minor Planet Mailing List (MPML) today about the 15th anniversary of the creation of the Torino Impact Hazard Scale otherwise known as the Torino Scale for short. The NASA JPL web site subtitles it as Assessing Asteroid And Comet Impact Hazard Predictions In The 21st Century. I attended the June 1999 international conference on near-Earth objects held in Turin Italy that voted to use the “Torino Scale” to describe threats for these objects. At the time I was the vice president of marketing and product development for Torus Technologies (now OMI). I was there to meet a customer and network with other potential customers who wanted to talk with me about remote search/survey projects. I was fascinated by the subject of the conference and for the chance to meet many well-known people in the field who I’d only read about. I was a very small fish in a big pond of experts. I feel privileged to have been at such a historic event with so many fascinating people from around the world.
At the time there was no agreed upon qualitative or quantitative scale to describe a genuine potential threat of a pending impact among astronomers or a good means to express this to the general public. Without such a method interpretation was ad hoc, which could lead to gross exaggeration and misinformation to the general public through the media. In a worse case it could cause unnecessary concern or even panic.
I was fascinated to watch and listen to the people at the conference during the presentations and discussions. There were strong opinions and the discussions sometimes became quite heated.
The Torino Scale uses a 0 to 10 scale rating of the actual threat of near earth objects (NEOs) with 0 indicating the likelihood of an impact as zero and 10 indicating a certain impact capable of creating a global climate catastrophe capable of destroying civilization as we know it. Unlike other quantitative scales such as the Richter scale for earthquake magnitudes or the Saffir-Simpson Hurricane Wind Scale, the Torino Scale is a qualitative scale giving a general assessment of a threat and the damage it might cause. This is because of the many unknowns (such as whether the object hits land or water, is a direct or glancing impact, proximity to populated areas, and so on). Also, fortunately, we have very few recent events of damage by such collisions to analyze directly.
The Torino Scale was changed slightly recently from the original one published in 2000 to better describe the attention or response to each category in the scale.