Hi Nick -

"When we count the NEO's and calculate their impact probability, and find that they cover 2/3 of the dents in the Moon and the Earth, over appropriate timescales, it tells us that unexpected "new" comets are a slim risk."

If only the dents were already fully counted, not only those on the Moon and Earth, but also those on Mars and the planets around Jupiter and Saturn!

It is by no means clear that comet impact is uniform over time, but instead comet impacts may enjoy a certain "periodicity", if you will. Unfortunately where we stand in this "period" is currently unknown, but you may wish to consider the data at this site:

http://www.jpl.nasa.gov/sl9/anim/keck_rmd.mpg

About your proposed wager, I don't know your age, but sadly the chances of me seeing 2030 are statistically pretty slim. In the event of an impact, the chances of me collecting from you on this would fall from nil to even less.

My favorite beverage was Paul Masson's Cold Duck chilled crystal cold, which tasted like Grape Nehi ( a soda-pop) with a kick. Unfortunately it is no longer manfuactured, which I guess would mkae its price comparable with that of Laphroaig.

ep