You quote me incorrectly. My actual words were "less than one in a million". I stated so because mine was a "naive calculation" that came up with 1/1332250000 to which I then applied a "discount by a factor of a thousand" precisely to address such arguments as yours.
To normalize your calculation properly you have to multiply 271.8*16,000. Now, can you do that arithmetic for us to complete your "critique"? On Wed, Feb 27, 2013 at 11:13 PM, George Paulson < [email protected]> wrote: > In an earlier message, James Bowery claimed that the odds of the Russian > meteor and asteroid DA14 passing Earth on the same day were "one in a > billion": > > http://www.mail-archive.com/[email protected]/msg76844.html > > "The odds of this coincidence are literally far less than one in a > million. The naive calculation is based on two like celestial events that > independently occur once in a hundred years occurring on the same day: > > 1/(365*100)^2 > = 1/1332250000 > > Note: that is one in a billion. Discount by a factor of a thousand for > whatever your argument is and you are still one in a million. > > This is not a coincidence." > > This is incorrect. It is more like the birthday problem, where we're looking > for the number of "years" that pass until two wandering asteroids have the > same "birthday". A birthday here is when they fly by the Earth. > > We can expect the fly by of a DA14 type object every 40 years. If we > also assume that something like the Russian meteor passes by every 40 years, > this gives us a 16,000 day "year", and with a Taylor expansion you get a > 99% probability of there being a coincident "birthday" after 271.8 "years", > or roughly 10,000 of our years. > > So we can expect an event like this once every 10,000 years. > >
