The Palermo Scale is used by astronomers to measure the risk imposed to earth by an asteroid. It’s a logarithmic scale with values ranging (roughly) from -7 to +7. The specks of dust that hit us every day are at the low end and the dinosaur killer-type would be at the high end. Anything less than -2 can be ignored, and those between -2 and zero merit careful monitoring. For the first time, an object with a value greater than zero has been discovered – 0.06. Further observations will modify this, hopefully back into negative territory. I went to post this to MetaFilter, but they’re [already on the case.