An error of a factor of 4 in assumed albedo leads to a factor of 2 error in size of the asteroid, and of the subsequent crater, should it hit something.

So this asteroid is now known to be 5 miles in diameter and would produce a crater 20 x 5 miles in dia on earth, if it hit - i.e. 100 miles. Not a patch on Chixulub but it would cure gridlock in LA in a moment!

Seriously, these errors are important. Given the scaling of energy as volume (r cubed) but light as area (r squared times albedo), errors in albedo translate to biassed errors in energy.

If we are equally likely to be under. exact, or over with our albedo estimates, by the same factor as we see here, then we see a radius spectrum of 0.5:1:2 (mean 1.17)

This gives an impact energy spectrum of 0.35:1:2.83 (mean 1.39), therefore the average energy per event is almost 40% greater than our estimates.

I donm't know if these uncertainties have been factored into all the claculations on risk, but clearly they ought to be.

(btw, EP, 140% of "bugger all" is still pretty damn small)