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cleanup
author Robert McIntyre <rlm@mit.edu>
date Thu, 20 Oct 2011 07:35:52 -0700
parents c29b950c8729
children 6842199d5e26
rev   line source
rlm@1 1 #+title: A Universe of Human Experience
rlm@1 2 #+author: Robert McIntyre
rlm@1 3 #+email: rlm@mit.edu
rlm@2 4 #+description: How many man-years are in a year?
rlm@2 5 #+keywords: man-year man-month man-hour universe human experience philosophy
rlm@1 6 #+setupfile: ../../aurellem/org/setup.org
rlm@1 7 #+include: ../../aurellem/org/level-0.org
rlm@2 8 #+babel: :results output :exports both
rlm@1 9
rlm@3 10 * What is a Man-Hour?
rlm@2 11
rlm@2 12 A [[http://en.wikipedia.org/wiki/Man-hour][/Man-Hour/]] is a term from the field of Management. It is one hour
rlm@2 13 of work by one person for a certain task.
rlm@2 14
rlm@2 15 For example, if I have a nine-to-five programming job at Initrode, but
rlm@2 16 I slack off most of the time and only /actually/ work from
rlm@2 17 10:00-11:00, then I only put in one man-hour of work a day.
rlm@2 18
rlm@2 19 If my task is simply existing, then I put in 24 man-hours of work
rlm@2 20 every day.
rlm@2 21
rlm@2 22
rlm@2 23 * Experience
rlm@2 24
rlm@2 25 I've often wondered what it would feel like to have more than one
rlm@2 26 body, and to experience the same day from different perspectives.
rlm@2 27
rlm@2 28 For example, there are around twenty different majors available at
rlm@2 29 MIT. If you had ten different bodies, and each of them double-majored
rlm@2 30 in different subjects, then in only four short years you would
rlm@2 31 graduate with a degree in every field MIT has to offer. You would have
rlm@2 32 experienced forty man-years of college in the process.
rlm@2 33
rlm@2 34 How many man-years does the entire MIT class experience every year?
rlm@2 35 [[http://web.mit.edu/fnl/volume/192/century.html][There were around]] $4585$ undergraduates at MIT in the fall of 1982.
rlm@2 36
rlm@2 37 $4585$ students $\times$ $1$ year $=$ $4585$ man-years.
rlm@2 38
rlm@2 39 One person could help lay the first blocks of [[http://en.wikipedia.org/wiki/Great_Pyramid_of_Giza][great Pharaoh Khufu's
rlm@2 40 tomb]] and live to see [[http://www.burjkhalifa.ae/][Burj Khalifa]] and they would accrue the same
rlm@2 41 amount of experience as the MIT class of '82 did in one year.
rlm@2 42
rlm@2 43
rlm@2 44 * Forever in a Day
rlm@2 45
rlm@2 46 How many man-years does everyone experience in a day? There are almost
rlm@2 47 7 billion people around today, according to [[http://www.census.gov/main/www/popclock.html][www.census.gov]].
rlm@2 48
rlm@2 49 #+begin_src clojure
rlm@2 50 (ns lifespan)
rlm@2 51 (use '[clojure.contrib [pprint :only [cl-format]]])
rlm@2 52
rlm@2 53 (cl-format *out* "Man-years per day: \n ~R"
rlm@2 54 (* 6969492979 ;; people on Earth
rlm@2 55 (/ 1 365) ;; years-per-day
rlm@2 56 ))
rlm@2 57 #+end_src
rlm@2 58
rlm@2 59 #+results:
rlm@2 60 : Man-years per day:
rlm@2 61 : nineteen million, ninety-four thousand, five hundred one
rlm@2 62
rlm@2 63 Together, we experience almost 20 million years every day!
rlm@2 64
rlm@2 65 A week in the lives of the people of Earth is enough to reach back to
rlm@2 66 the age of the dinosaurs.
rlm@2 67
rlm@2 68
rlm@2 69 * The Infinite Stories of Humanity
rlm@2 70
rlm@2 71 How many man-years is the sum total of human experience? That is, how
rlm@2 72 many man-years has every human who has ever lived experienced?
rlm@2 73
rlm@2 74 Using a very rough calculation involving the table from [[http://www.prb.org/Articles/2002/HowManyPeopleHaveEverLivedonEarth.aspx][here]] and the
rlm@2 75 average human lifespans through the ages found [[http://en.wikipedia.org/wiki/Life_expectancy][here]], I get the
rlm@2 76 following:
rlm@2 77
rlm@2 78 #+begin_src clojure
rlm@2 79 (in-ns 'lifespan)
rlm@2 80 (use '[clojure.contrib [def :only [defvar]]])
rlm@2 81
rlm@2 82 (defvar
rlm@2 83 time-periods
rlm@2 84 [:start-8000BC
rlm@2 85 :8000BC-1
rlm@2 86 :1-1200
rlm@2 87 :1200-1650
rlm@2 88 :1650-1750
rlm@2 89 :1750-1850
rlm@2 90 :1850-1900
rlm@2 91 :1900-1950
rlm@2 92 :1950-1995
rlm@2 93 :1995-2011]
rlm@2 94 "The time periods under question.
rlm@2 95 'start' here is taken to be 50,000BC")
rlm@2 96
rlm@2 97 (defvar births
rlm@2 98 (zipmap
rlm@2 99 time-periods
rlm@2 100 [ 1137789769 ;; \
rlm@2 101 46025332354 ;; |
rlm@2 102 26591343000 ;; |
rlm@2 103 12782002453 ;; |
rlm@2 104 3171931513 ;; | -- from the video at:
rlm@2 105 4046240009 ;; | http://www.prb.org/Articles/2002/
rlm@2 106 2900237856 ;; | HowManyPeopleHaveEverLivedonEarth.aspx
rlm@2 107 3390198215 ;; |
rlm@2 108 5427305000 ;; |
rlm@2 109 2130327622]);; /
rlm@2 110 "number of people who existed in the given time periods")
rlm@2 111
rlm@2 112 ;; Confirm that the sum of people agrees with that in the video.
rlm@2 113 (assert (= 107602707791 (reduce + (vals births))))
rlm@2 114
rlm@2 115 (defvar lifespans
rlm@2 116 (zipmap
rlm@2 117 time-periods
rlm@2 118 [33 ;; start-8000BC \
rlm@2 119 22 ;; 8000BC-1 | -- from:
rlm@2 120 30 ;; 1-1200 | http://en.wikipedia.org/wiki/
rlm@2 121 32 ;; 1200-1650 / Life_expectancy
rlm@2 122 35 ;; 1650-1750 \
rlm@2 123 35 ;; 1750-1850 |-- from:
rlm@2 124 45 ;; 1850-1900 | http://www.deathreference.com/
rlm@2 125 66 ;; 1900-1950 | Ke-Ma/Life-Expectancy.html
rlm@2 126 66 ;; 1950-1995 /
rlm@2 127 70 ;; 1995-2011-------> form:
rlm@2 128 ;; http://www.prb.org/DataFinder/Topic/
rlm@2 129 ;; Rankings.aspx?ind=6&loc=241
rlm@2 130 ])
rlm@2 131 "lifespans in years from birth for the various time periods")
rlm@2 132
rlm@2 133
rlm@2 134
rlm@2 135
rlm@3 136
rlm@3 137 ;; This section is just here to make the result look pretty.
rlm@2 138 (dorun
rlm@2 139 (map println
rlm@2 140 (clojure.contrib.string/split
rlm@2 141 #","
rlm@3 142 (cl-format
rlm@3 143 nil "years of human experience: \n ~R years"
rlm@3 144 ;; Multiply each time-period's total number of people
rlm@3 145 ;; by those people's average lifespan in years to get
rlm@3 146 ;; the total number of man-years experienced during
rlm@3 147 ;; that period, then add them together.
rlm@3 148 (reduce +
rlm@3 149 (map *
rlm@3 150 (map births time-periods)
rlm@3 151 (map lifespans time-periods)))))))
rlm@2 152
rlm@2 153 #+end_src
rlm@2 154
rlm@2 155 #+results:
rlm@2 156 : years of human experience:
rlm@2 157 : three trillion
rlm@2 158 : three hundred seventy-one billion
rlm@2 159 : ninety-three million
rlm@2 160 : five hundred ninety-five thousand
rlm@2 161 : one hundred eighty-one years
rlm@2 162
rlm@2 163
rlm@2 164
rlm@2 165 Humans have already collectively lived far longer than the age of the
rlm@2 166 universe.