271.8*16,000 comes out to 4,348,800 days. 4,348,800/365 comes out to 11,915 years.
So like I said we can expect an event like this roughly every 10,000 years or so. That's a far cry from the one in one billion odds or the one in one million odds after discounting by a factor of a thousand, isn't it? Date: Thu, 28 Feb 2013 01:04:34 -0600 Subject: Re: [Vo]:Russian meteor coincidence odds From: [email protected] To: [email protected] 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.
