Saturday, March 19, 2011

Death and Presidents

A few years back, an older friend told me a story about her grandmother.  It was November 1963, and her grandmother had just turned 105.  My friend went to visit her grandmother in the hospital.

Friend: "Grammy, the president's been shot!"
Grandmother: "Another one?!"

It was then that I realized her grandmother had lived (and was old enough to remember) every presidential shooting from Lincoln to Kennedy.  It blew my mind.

It's amazing how much can happen in a lifetime.  This point was driven home in a recent post on Reddit.  As of March 2011, our 10th president John Tyler (born 1790) had two living grand children!  This got me thinking: If you passed a baton from person to person, what's the least number of hands it could touch and reach the first even human?

According to Wikipedia, modern humans showed up about 200,000 years ago.  If you passed the baton from a centenarian to a new born that would live to be a centenarian, it would take only 2000 people.1   This is roughly the number of people attending my high school.  If you wanted to go back to the time of Christ, it would only take 20 people. 

[1] Some people will no doubt quibble that the average life span was in the 30s for much of our history.  True, but this neglects two points.  First, we're doing an order of magnitude estimate and this fact won't change the answer by an order of magnitude.  More importantly, "life expectancy" is the average life span.  Life expectancy may have been low, but this was largely due to high infant mortality rates.  Back in the day, if you were lucky enough to make it to adulthood, you stood a good chance of making it to old age.  Since we're only looking for the oldest person at any one time, there's a good chance there was centenarian somewhere in the world.


  1. About twenty years ago I wrote an article for an science magazine on using millimetre waves for communication (it might happen yet!). Whilst I was writing the article the (then) oldest person in the world died. She was a teenager when Hertz discovered radio waves; when she died we had sophisticated cellular radio systems with phones in our pockets. As you say, a lot can happen in one lifetime.

  2. Wow, SysEngShep! That blows my mind. I'm starting to realize people of older generations are an amazing resource for knowing what it was like "back in the day". It's sad to think that each year, mankind forever loses the last actual memories of events that took place roughly one hundred years prior. I'm suddenly struck with the urge to call some grandparents.

  3. Relevant: Last living person that saw Lincoln's assassination in 1956.