the flyby is a longer event than a single hour. On Thu, Feb 28, 2013 at 11:41 AM, James Bowery <[email protected]> wrote:
> You obviously misunderstand the Poisson process and/or my calculation. > > There is nothing about any specific date in it. > > > > On Thu, Feb 28, 2013 at 12:22 PM, George Paulson < > [email protected]> wrote: > >> James, >> >> Your calculation was of the odds of a simultaneous flyby occurring on >> February 15th, 2013, that is, occurring on a specific date. The odds of it >> occurring on another specific date, say tomorrow, March 1st, 2013, are also >> as low as you calculated. >> >> The odds of it happening in general, that is on any day rather than on a >> particular date, are much higher. >> >> If we're trying to make some reasonable judgments about possible causes, >> it seems we should test our speculations against these latter odds, rather >> than the former odds, unless there is something special about that >> particular date, Feb. 15th, 2013, or some other reason or piece of >> information that suggests we should pay attention to the odds of the flyby >> occurring on that day, rather than any day. >> >> ------------------------------ >> Date: Thu, 28 Feb 2013 09:30:52 -0600 >> >> Subject: Re: [Vo]:Russian meteor coincidence odds >> From: [email protected] >> To: [email protected] >> >> If my counting units had been years then you'd be right to imply my >> degree of error was wildly off the mark, but they weren't. If the two >> events had occurred within the same hour instead of within the same day, my >> calculation would have been an even greater "far cry" from the time base of >> years but it is still reasonable to base the calculation on counting units >> derived from the distance in time between the events. What if they had >> occurred within the same minute? The same second? >> >> In fact, the two events occurred within 16 hours of each other, not 24 >> hours. >> >> Otherwise, thanks for pursuing a less naive calculation but you failed to >> show your work. "Taylor expansion" doesn't cut it. >> >> Please update it for 16 hours rather than 24 hours and show your work. >> By work I mean something more specific than "taylor expasion" which is >> about as vague as you can get. >> >> >> >> On Thu, Feb 28, 2013 at 2:36 AM, George Paulson < >> [email protected]> wrote: >> >> 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. >> >> >> >> >
