Explain xkcd: It's 'cause you're dumb.
Title text: The universe is probably littered with the one-planet graves of cultures which made the sensible economic decision that there's no good reason to go into space--each discovered, studied, and remembered by the ones who made the irrational decision.
In this comic, over 65 years, Randall is projecting the number of living humans who have walked on another world, which seems to include the moon as well. He is using actuarial tables or life tables which shows for each age the probability that a certain person will be alive by their next birthday.
This comic assumes that no one else is going to walk on another world going forward into the future which, as is mentioned in the image text, is a terrible idea for the future of the human race. If the human race only exists on one planet - one disaster can destroy the whole race. However, if humans extend their society to other planets, they lessen the risk of complete extinction.
- [A graph titled 'Number of Living Humans Who Have Walked on Another World' -- its y-axis is numbered 5, 10, 15, it's x-axis increments every ten years from 1960-2040. The line of the graph has a bracket above it that says '65 Years', starting at 1969, ending in 2034.
- The line starts at 1969 and increases steeply to 12 by 1972. It then plateaus until the early nineties declines gradually to 9 between 1991-1999, and then plateaus again.
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- From 2020-2035, which is labeled 'Projected Actuarial Tables', the line branches into three and begins to decline more steeply to zero. The area between the first and second branch is shaded and labeled '5th percentile' and the area between the second and third branch is shaded and labeled '95th percentile.']
I wonder if it would be possible to identify individual people who are behind those vertical jumps in the graph (in the not projected part)... --JakubNarebski (talk) 19:18, 14 December 2012 (UTC)
- Glad you asked! </Information Hen> Neil Armstrong and Buzz Aldrin landed in July 1969; that's two. Pete Conrad and Alan Bean joined the group that November; that's four. Alan Shepard and Edgar Mitchell in February '71; that's six. David Scott and James Irwin in July '71; that's eight. John W. Young and Charles Duke in April '72; that's ten. Eugene Cernan and Harrison Schmitt in December '72; that's twelve. Irwin died in '91, dropping it to 11. Shepard and Conrad died in '98 and '99 respectively, making it 9 as of the date this comic was published. Armstrong died in '12, so our current number is 8. The oldest living person to have landed on the moon is Aldrin, 83. There are two 82-year-olds, two 80s, one 78 and two 77s. Ekedolphin (talk) 13:28, 27 January 2013 (UTC)
Almost prophetic and very, very sad. RIP Neil Armstrong ------
Can we add the 5% and 95% columns to the table? Spongebog (talk)
- i dont feel like this would add to the explanation of the comic and would require us to know a great deal about the author's calculations. rather than attempt to redo the actuarial calculations performed to make the chart and assign this to the individuals in the table we should rather explain the concepts behind the 5% and 95% and preserve the intention of actuarial information as applying to demographic groups. 5% of people in the demographic the author selected live to _ age 95% of those people live to _ age and how this affects our subject population. Mrarch (talk) 21:43, 6 December 2013 (UTC)