Yellow forever

[mmcirvin]

An article on revisions of the Torino asteroid-threat scale finally mentions the most obvious thing about it: that it almost certainly inspired the Department of Homeland Security's terrorism-alert scale.

The thing is, while there are cosmetic similarities, the intention of the two scales is actually different. The Torino scale is mostly supposed to have a calming effect: it was established after a number of potential impactors got far more dire publicity than they deserved, and is intended to put across the idea that though there are always potential impactors with a nonzero probability of hitting the Earth, the fact that astronomers are looking into one doesn't mean that the danger is unusually high. There's a recognition that a certain level of risk is normal and it's pointless to keep people scared all the time.

The DHS's terrorism scale, on the other hand, is supposed to keep you at a vaguely elevated level of anxiety all the time; the normal threat level is really yellow, not green.

Comments

[zmook.livejournal.com]

One interesting bit that snuck into the article is the illustration on the whiteboard behind Binzel -- I'd never seen the technical version of the scale before. The sequence of numbers assigned to boxes 2 through 6 is sort of surprising: in 2-v-3, the higher probability of local effect is rated as more serious than the lower probability of widespread effect, but 5-v-6 are reversed.

[mmcirvin.livejournal.com]

My guess is that that's because, at the low-probability end of the space, everything you see is likely to go away in a few days as data get better, even if it's a potential humanity-killer in size.