Odd about the Peterboroughs, but perhaps not as much as you think.
Used to live in Ottawa, Canada, and Peterborough, Ontario, brings pleasant visits to mind. A completley unrelated coincidence.
Back to assessing how odd your meeting here is: Not very.
Detail (I think I have this right):
Assume 6.5 billion people on the planet.
Assume 10 % are potentially members (some command of English in written form, access to internet, with free time/money to devote to a flashlight/electronic hobby, fit our demographics, etc.
5000 members in 2005, Google did not give me a newer number, say 10,000 now, assume all active, for now.
We will asssume there are ONLY two Peterboroughs in the world, for now.
Population of Peterborough, Ontario, Canada: 74,000.
Population of Peterborough, England, 160,000
Probability that a random resident of either city is a potential CPF member is almost 100%. That is to say, they are in the 10% or the world population guesstimated to be potential members. We will assume that there is no effect of country on the membership percentages. Though I am sure a Moderator could hone this closer with those figures.
Among potential members, actual members are estimated to be about 10,000 out of 650 million worldwide. Or 0.0015 % of all potential members ARE CPF members.
So 99.85 % of these cities' populations would be expected NOT to be members.
The probability of AT LEAST ONE CPF member is 1 MINUS the probability that there are none in a given city. The probability of none is the probability of each resident not being a CPF member raised to the power of the population.
So the probability that there is at least one CPF member from Perterborough, Ontario, is about 68%. Likewise, at least one from Perterborogh England is about 91% probable.
(The sizes of the cities is more important than the exact percentage of CPF members to potentilal members because raising a number less thatn one to the power of a large number makes a small number.)
The probability of at least one CPF member from BOTH Peterboroughs is
the product of those two probabilites or about 63%.
A lot of CPF members are no longer active, or participate in diverse areas and don't meet here in Bicycles. Biking may be a more universal interest than lights for hunting, for example, but a small portion of cyclists come here. I would hazard that the latest crop of LED's has stirred the cycling community up and added membership to CPF. It is hard to estimate your chances of bumping into each other, had you joined randomly with different intests over the age of the forum. But with one a two-month member the other almost a 2-year, and lots of bike threads, interested in bikes, it appears to be inevitable.
There are likely Perterboroughs in the US, or New Zealand, South Africa, or Australia, even in multiple provinces or states of these countries. The addition on one more Peterborough would give three unique two-city combinations, four Peterboroughs give 6 such combinations, and with each additional Peterborogh the number of unique two-city pairs combinatorics mean the combinations escalate rapidly. Peterboroughs of only 100 people would not contribute much to the total probability though. Probability suggests that you come from the largest or one of the largest population pairs.
So the odds seem to be pretty good to meet someone from another city the same name as yours IF those cities are about 100,000 or larger and more so if the name is used frequently across the globe. This is similar to finding someone that has your birth date at a party of 20-30 people. A seemingly surprising occurence that is quite common because it is fairly likely.
Some coincidences are a lot less coincidental than they first appear.
Still, this is pretty neat, eh? (You can take the Canuck out of Canada but not the Canadian out of the Canuck.)
Small world etc. Hope you enjoyed this. A fun exercise in probability.:sick2:
why not a standard battery box that holds 2x18650's or even 4 li-ons with the ability to put what ever drop in you wanted. that way as led tech improves you only have to change the drop in and replace batterys as they fail
