# HG changeset patch # User Robert McIntyre # Date 1319120533 25200 # Node ID c29b950c87298d1346777b6930d9e2ceaef0f133 # Parent bfd876105ebd14681a31543ac7aa2005da0de5ec first draft of man-hours is complete diff -r bfd876105ebd -r c29b950c8729 org/man-years.org --- a/org/man-years.org Thu Oct 20 01:13:26 2011 -0700 +++ b/org/man-years.org Thu Oct 20 07:22:13 2011 -0700 @@ -1,8 +1,163 @@ #+title: A Universe of Human Experience #+author: Robert McIntyre #+email: rlm@mit.edu -#+description: how many man-years are in a year? -#+keywords: man-year man-month universe human experience philosophy +#+description: How many man-years are in a year? +#+keywords: man-year man-month man-hour universe human experience philosophy #+setupfile: ../../aurellem/org/setup.org #+include: ../../aurellem/org/level-0.org +#+babel: :results output :exports both +* What is a Man-Hour + +A [[http://en.wikipedia.org/wiki/Man-hour][/Man-Hour/]] is a term from the field of Management. It is one hour +of work by one person for a certain task. + +For example, if I have a nine-to-five programming job at Initrode, but +I slack off most of the time and only /actually/ work from +10:00-11:00, then I only put in one man-hour of work a day. + +If my task is simply existing, then I put in 24 man-hours of work +every day. + + +* Experience + +I've often wondered what it would feel like to have more than one +body, and to experience the same day from different perspectives. + +For example, there are around twenty different majors available at +MIT. If you had ten different bodies, and each of them double-majored +in different subjects, then in only four short years you would +graduate with a degree in every field MIT has to offer. You would have +experienced forty man-years of college in the process. + +How many man-years does the entire MIT class experience every year? +[[http://web.mit.edu/fnl/volume/192/century.html][There were around]] $4585$ undergraduates at MIT in the fall of 1982. + +$4585$ students $\times$ $1$ year $=$ $4585$ man-years. + +One person could help lay the first blocks of [[http://en.wikipedia.org/wiki/Great_Pyramid_of_Giza][great Pharaoh Khufu's +tomb]] and live to see [[http://www.burjkhalifa.ae/][Burj Khalifa]] and they would accrue the same +amount of experience as the MIT class of '82 did in one year. + + +* Forever in a Day + +How many man-years does everyone experience in a day? There are almost +7 billion people around today, according to [[http://www.census.gov/main/www/popclock.html][www.census.gov]]. + +#+begin_src clojure +(ns lifespan) +(use '[clojure.contrib [pprint :only [cl-format]]]) + +(cl-format *out* "Man-years per day: \n ~R" + (* 6969492979 ;; people on Earth + (/ 1 365) ;; years-per-day + )) +#+end_src + +#+results: +: Man-years per day: +: nineteen million, ninety-four thousand, five hundred one + +Together, we experience almost 20 million years every day! + +A week in the lives of the people of Earth is enough to reach back to +the age of the dinosaurs. + + +* The Infinite Stories of Humanity + +How many man-years is the sum total of human experience? That is, how +many man-years has every human who has ever lived experienced? + +Using a very rough calculation involving the table from [[http://www.prb.org/Articles/2002/HowManyPeopleHaveEverLivedonEarth.aspx][here]] and the +average human lifespans through the ages found [[http://en.wikipedia.org/wiki/Life_expectancy][here]], I get the +following: + +#+begin_src clojure +(in-ns 'lifespan) +(use '[clojure.contrib [def :only [defvar]]]) + +(defvar + time-periods + [:start-8000BC + :8000BC-1 + :1-1200 + :1200-1650 + :1650-1750 + :1750-1850 + :1850-1900 + :1900-1950 + :1950-1995 + :1995-2011] + "The time periods under question. + 'start' here is taken to be 50,000BC") + +(defvar births + (zipmap + time-periods + [ 1137789769 ;; \ + 46025332354 ;; | + 26591343000 ;; | + 12782002453 ;; | + 3171931513 ;; | -- from the video at: + 4046240009 ;; | http://www.prb.org/Articles/2002/ + 2900237856 ;; | HowManyPeopleHaveEverLivedonEarth.aspx + 3390198215 ;; | + 5427305000 ;; | + 2130327622]);; / + "number of people who existed in the given time periods") + +;; Confirm that the sum of people agrees with that in the video. +(assert (= 107602707791 (reduce + (vals births)))) + +(defvar lifespans + (zipmap + time-periods + [33 ;; start-8000BC \ + 22 ;; 8000BC-1 | -- from: + 30 ;; 1-1200 | http://en.wikipedia.org/wiki/ + 32 ;; 1200-1650 / Life_expectancy + 35 ;; 1650-1750 \ + 35 ;; 1750-1850 |-- from: + 45 ;; 1850-1900 | http://www.deathreference.com/ + 66 ;; 1900-1950 | Ke-Ma/Life-Expectancy.html + 66 ;; 1950-1995 / + 70 ;; 1995-2011-------> form: + ;; http://www.prb.org/DataFinder/Topic/ + ;; Rankings.aspx?ind=6&loc=241 + ]) + "lifespans in years from birth for the various time periods") + + + +;; multiply each time-period's total number of people +;; by those people's average lifespan in years to get +;; the total number of man-years experienced during +;; that period, then add them together. + +(dorun + (map println + (clojure.contrib.string/split + #"," + (cl-format nil "years of human experience: \n ~R years" + (reduce + + (map * + (map births time-periods) + (map lifespans time-periods))))))) + +#+end_src + +#+results: +: years of human experience: +: three trillion +: three hundred seventy-one billion +: ninety-three million +: five hundred ninety-five thousand +: one hundred eighty-one years + + + +Humans have already collectively lived far longer than the age of the +universe.