“New images from Titan,” http://www.esa.int/Our_Activities/Space_Science/Cassini-Huygens/New_images_from_Titan
Yoda
Saturday Morning Breakfast Cereal, http://www.smbc-comics.com/index.php?db=comics&id=2305#comic
Youtube, “ ‘Beethoven Virus’—Musical Tesla Coils,” http://www.youtube.com/watch?v=uNJjnz-GdlE
“Beast.” The 15Kw 7' tall DR (DRSSTC 5), http://www.goodchildengineering.com/tesla-coils/drsstc-5-10kw-monster
Falling with Helium
De Haven, H., “Mechanical analysis of survival in falls from heights of fifty to one hundred and fifty feet,” Injury Prevention, 6(1):62-b-68, http://injuryprevention.bmj.com/content/6/1/62.3.long
“Armchair Airman Says Flight Fulfilled His Lifelong Dream,” New York Times, July 4, 1982, http://www.nytimes.com/1982/07/04/us/armchair-airman-says-flight-fulfilled-his-lifelong-dream.html?pagewanted=all
Jason Martinez, “Falling Faster than the Speed of Sound,” Wolfram Blog, October 24, 2012, http://blog.wolfram.com/2012/10/24/falling-faster-than-the-speed-of-sound
Everybody Out
Project Orion: The True Story of the Atomic Spaceship,http://www.amazon.com/Project-Orion-Story-Atomic-Spaceship/dp/0805059857
Self-Fertilization
“Sperm Cells Created From Human Bone Marrow,” http://www.sciencedaily.com/releases/2007/04/070412211409.htm
Nayernia, Karim, Tom Strachan, Majlinda Lako, Jae Ho Lee, Xin Zhang, Alison Murdoch, John Parrington, Miodrag Stojkovic, David Elliott, Wolfgang Engel, Manyu Li, Mary Herbert, and Lyle Armstrong, “RETRACTION-In Vitro Derivation Of Human Sperm From Embryonic Stem Cells,” Stem Cells and Development (2009): 0908w75909069.
“Can sperm really be created in a laboratory?” http://www.theguardian.com/lifeandstyle/2009/jul/09/sperm-laboratory-men
This is discussed more deeply in F. M. Lancaster’s monograph Genetic and Quantitative Aspects of Genealogy at http://www.genetic-genealogy.co.uk/Toc115570144.html.
High Throw
“A Prehistory of Throwing Things,” http://ecodevoevo.blogspot.com/2009/10/prehistory-of-throwing-things.html
“Chapter 9. Stone tools and the evolution of hominin and human cognition,” http://www.academia.edu/235788/Chapter_9._Stone_tools_and _the_evolution_of_hominin_and_human_cognition
“The unitary hypothesis: A common neural circuitry for novel manipulations, language, plan-ahead, and throwing?” http://www.williamcalvin.com/1990s/1993Unitary.htm
“Evolution of the human hand: The role of throwing and clubbing,” http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1571064
“Errors in the control of joint rotations associated with inaccuracies in overarm throws,” http://jn.physiology.org/content/75/3/1013.abstract
“Speed of Nerve Impulses,” http://hypertextbook.com/facts/2002/DavidParizh.shtml
“Farthest Distance to Throw a Golf Ball,” http://recordsetter.com/world-record/world-record-for-throwing-golf-ball/7349#contentsection
Lethal Neutrinos
Karam, P. Andrew. “Gamma and Neutrino Radiation Dose from Gamma Ray Bursts and Nearby Supernovae,” Health Physics 82, no. 4 (2002): 491–99.
Speed Bump
“Speed bump-induced spinal column injury,” http://akademikpersonel.duzce.edu.tr/hayatikandis/sci/hayatikandis12.01.2012_08.54.59sci.pdf
“Speed hump spine fractures: Injury mechanism and case series,” http://www.ncbi.nlm.nih.gov/pubmed/21150664
“The 2nd American Conference on Human Vibration,” http://www.cdc.gov/niosh/mining/UserFiles/works/pdfs/2009-145.pdf
“Speed bump in Dubai + flying Gallardo,” http://www.youtube.com/watch?v=Vg79_mM2CNY
Parker, Barry R., “Aerodynamic Design,” The Isaac Newton School of Driving: Physics and your car.” Baltimore, MD: Johns Hopkins University Press, 2003, 155.
The Myth of the 200-mph “Lift-Off Speed.” http://www.buildingspeed.org/blog/2012/06/the-myth-of-the-200-mph-lift-off-speed/
“Mercedes CLR-GTR Le Mans Flip,” http://www.youtube.com/watch?v=rQbgSe9S54I
National Highway Transportation NHTSA, Summary of State Speed Laws, 2007
“FedEx still faster than the Internet,” http://royal.pingdom.com/2007/04/11/fedex-still-faster-than-the-internet
“Cisco Visual Networking Index: Forecast and Methodology, 2012–2017,” http://www.cisco.com/en/US/solutions/collateral/ns341/ns525/ns537/ns705/ns827/white_paper_c11-481360_ns827_Networking _Solutions_White_Paper.html
“Intel® Solid-State Drive 520 Series,” http://download.intel.com/newsroom/kits/ssd/pdfs/intel_ssd_520_product_spec_325968.pdf
“Trinity test press releases (May 1945),” http://blog.nuclearsecrecy.com/2011/11/10/weekly-document-01
“NEC and Corning achieve petabit optical transmission,” http://optics.org/news/4/1/29
Free Fall
“Super Mario Bros.—Speedrun level 1-1 [370],” http://www.youtube.com/watch?v=DGQGvAwqpbE
“Sprint ring cycle,” http://www1.sprintpcs.com/support/HelpCenter.jsp?FOLDER%3C%3Efolder_id=1531979#4
“Glide data,” http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=577711#577711
“Jump. Fly. Land.,” Air & Space, http://www.airspacemag.com/flight-today/Jump-Fly-Land.html
Prof. Dr. Herrligkoffer, “The East Pillar of Nanga Parbat,” The Alpine Journal (1984).
The Guestroom, “Dr. Glenn Singleman and Heather Swan,” http://www.abc.net.au/local/audio/2010/08/24/2991588.htm
“Highest BASE jump: Valery Rozov breaks Guinness world record,” http://www.worldrecordacademy.com/sports/highest_BASE_jump_Valery_Rozov_breaks_Guinness_world_record_213415.html
Dean Potter, “Above It All,” http://www.tonywingsuits.com/deanpotter.html
Sparta
According to a random stranger on the Internet, Andy Lubienski, “The Longbow,” http://www.pomian.demon.co.uk/longbow.htm
Drain the Oceans
Extrapolated from the maximum pressure tolerable by icebreaker ship hull plates: http://www.iacs.org.uk/document/public/Publications/Unified_requirements/PDF/UR_I_pdf410.pdf
“An experimental study of critical submergence to avoid free-surface vortices at vertical intakes,” http://www.leg.state.mn.us/docs/pre2003/other/840235.pdf
Drain the Oceans: Part II
Donald Rapp, “Accessible Water on Mars,” JPL D-31343-Rev.7, http://spaceclimate.net/Mars.Water.7.06R.pdf
D. L. Santiago et al., “Mars climate and outflow events,” http://spacescience.arc.nasa.gov
D. L. Santiago et al., “Cloud formation and water transport on Mars after major outflow events,” 43rd Planetary Science Conference (2012).
Maggie Fox, “Mars May Not Have Been Warm or Wet,” http://rense.com/general32/marsmaynothave.htm
Twitter
The Story of Mankind, http://books.google.com/books?id=RskHAAAAIAAJ&pg=PA1#v=onepage&q&f=false
“Counting Characters,” https://dev.twitter.com/docs/counting-characters
“A Mathematical Theory of Communication,” http://cm.bell-labs.com/cm/ms/what/shannonday/shannon1948.pdf
Lego Bridge
“How tall can a Lego tower get?” http://www.bbc.co.uk/news/magazine-20578627
“Investigation Into the Strength of Lego Technic Beams and Pin Connections,” http://eprints.usq.edu.au/20528/1/Lostroh_LegoTesting_2012.pdf
“Total value of property in London soars to £1.35trn,” http://www.standard.co.uk/business/business-news/total-value-of-property-in-london-soars-to-135trn-8779991.html
Random Sneeze Call
Cari Nierenberg, “The Perils of Sneezing, ABC News,” Dec. 22, 2008. http://abcnews.go.com/Health/ColdandFluNews/story?id=6479792&page=1
Hayden, and Robert J. Sherertz, “ ‘Gesundheit!’ Sneezing, Common Colds, Allergies, and Staphylococcus aureus Dispersion,” J Infect Dis. (2006), 194 (8): 1119–1126 doi:10.1086/507908
“Annual Rates of Lightning Fatalities by Country” http://www.vaisala.com/Vaisala%20Documents/Scientific %20papers/Annual_rates_of_lightning_fatalities_by_country.pdf
Expanding Earth
“In conclusion, no statistically significant present expansion rate is detected by our study within the current measurement uncertainty of 0.2 mm yr−1.”
Wu, X., X. Collilieux, Z. Altamimi, B. L. A. Vermeersen, R. S. Gross, and I. Fukumori (2011), “Accuracy of the International Terrestrial Reference Frame origin and Earth expansion, Geophys.” Res. Lett., 38, L13304, doi:10.1029/2011GL047450, http://repository.tudelft.nl/view/ir/uuid%3A72ed93c0-d13e-427c-8c5f-f013b737750e/
Lawrence Grybosky, “Thermal Expansion and Contraction,” http://www.engr.psu.edu/ce/courses/ce584/concrete/library/cracking/thermalexpansioncontraction/thermalexpcontr.htm
Sasselov, Dimitar D., The life of super-Earths: How the hunt for alien worlds and artificial cells will revolutionize life on our planet. New York: Basic Books, 2012.
Franz, R.M. and P. C. Schutte, “Barometric hazards within the context of deep-level mining,” The Journal of The South African Institute of Mining and Metallurgy
Plummer, H. C., “Note on the motion about an attracting centre of slowly increasing mass,” Monthly Notices of the Royal Astronomical Society, Vol. 66, p. 83, http://adsabs.harvard.edu/full/1906MNRAS..66...83P
Weightless Arrow
“Hunting Arrow Selection Guide: Chapter 5,” http://www.huntersfriend.com/carbon_arrows/hunting_arrows_selection_guide_chapter_5.htm
“USA Archery Records, 2009,” http://www.usaarcheryrecords.org/FlightPages/2009/2009%20World%20Regular%20Flight%20Records.pdf
“Air flow around the point of an arrow,” http://pip.sagepub.com/content/227/1/64.full.pdf
STS-124: KIBO, NASA, http://www.nasa.gov/pdf/228145main_sts124_presskit2.pdf
Sunless Earth
“The 1859 Solar–Terrestrial Disturbance and the Current Limits of Extreme Space Weather Activity,” http://www.leif.org/research/1859%20Storm%20-%2Extreme%20Space%20Weather.pdf
“The extreme magnetic storm of 1–2 September 1859,” http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/8787/1/02-1310.pdf
“Geomagnetic Storms,” http://www.oecd.org/governance/risk/46891645.pdf
“Normalized Hurricane Damage in the United States: 1900–2005,” http://sciencepolicy.colorado.edu/admin/publication_files/resource-2476-2008.02.pdf
“A Satellite System for Avoiding Serial Sun-Transit Outages and Eclipses,” http://www3.alcatel-lucent.com/bstj/vol49-1970/articles/bstj49-8-1943.pdf
“Impacts of Federal-Aid Highway Investments Modeled by NBIAS,” http://www.fhwa.dot.gov/policy/2010cpr/chap7.htm#9
“Time zones matter: The impact of distance and time zones on services trade,” http://eeecon.uibk.ac.at/wopec2/repec/inn/wpaper/2012-14.pdf
“Baby Fact Sheet,” http://www.ndhealth.gov/familyhealth/mch/babyfacts/Sunburn.pdf
“The photic sneeze reflex as a risk factor to combat pilots,” http://www.ncbi.nlm.nih.gov/pubmed/8108024
“Burned by wild parsnip,” http://dnr.wi.gov/wnrmag/html/stories/1999/jun99/parsnip.htm
Updating a Printed Wikipedia
BrandNew: “Wikipedia as a Printed Book,” http://www.brandnew.uk.com/wikipedia-as-a-printed-book/
ToolServer: Edit rate, http://toolserver.org/~emijrp/wmcharts/wmchart0001.php
QualityLogic: Cost of Ink Per Page Analysis, June 2012, http://www.qualitylogic.com/tuneup/uploads/docfiles/QualityLogic-Cost-of-Ink-Per-Page-Analysis _US_1-Jun-2012.pdf
Sunset on the British Empire
“Eddie Izzard-Do you have a flag?” http://www.youtube.com/watch?v=uEx5G-GOS1k
“This Sceptred Isle: Empire. A 90 part history of the British Empire,” http://www.bbc.co.uk/radio4/history/empire/map
“A Guide to the British Overseas Territories,” http://www.telegraph.co.uk/news/wikileaks-files/london-wikileaks/8305236/A-GUIDE-TO-THE-BRITISH-OVERSEAS-TERRITORIES.html
“Trouble in Paradise,” http://www.vanityfair.com/culture/features/2008/01/pitcairn200801
“Long History of Child Abuse Haunts Island ‘Paradise,’” http://www.npr.org/templates/story/story.php?storyId=103569364
“JavaScript Solar Eclipse Explorer,” http://eclipse.gsfc.nasa.gov/JSEX/JSEX-index.html
Stirring Tea
“Brawn Mixer, Inc., Principles of Fluid Mixing (2003),” http://www.craneengineering.net/products/mixers/documents/craneEngineeringPrinciplesOfFluidMixing.pdf
“Cooling a cup of coffee with help of a spoon,” http://physics.stackexchange.com/questions/5265/cooling-a-cup-of-coffee-with-help-of-a-spoon/5510#5510
All the Lightning
“Introduction to Lightning Safety,” National Weather Service, Wilmington, Ohio, http://www.erh.noaa.gov/iln/lightning/2012/lightningsafetyweek.php
Bürgesser Rodrigo E., Maria G. Nicora, and Eldo E. Ávila, “Characterization of the lightning activity of Relámpago del Catatumbo,’’ Journal of Atmospheric and Solar-Terrestrial Physics (2011), http://wwlln.net/publications/avila.Catatumbo2012.pdf
Loneliest Human
BBC Future interview with Al Wolden (April 2, 2013), http://www.bbc.com/future/story/20130401-the-loneliest-human-being/1
Raindrop
“SSMI/SSMIS/TMI-derived Total Precipitable Water-North Atlantic,” http://tropic.ssec.wisc.edu/real-time/mimic-tpw/natl/main.html
“Structure of Florida Thunderstorms Using High-Altitude Aircraft Radiometer and Radar Observations,” Journal of Applied Meteorology, http://rsd.gsfc.nasa.gov/912/edop/misc/1736.pdf
SAT Guessing
Cooper, Mary Ann, MD., “Disability, Not Death Is the Main Problem with Lightning Injury,” http://www.uic.edu/labs/lightninginjury/Disability.pdf
National Oceanic and Atmospheric Administration (NOAA), “2008 Lightning Fatalities,” http://www.nws.noaa.gov/om/hazstats/light08.pdf
Neutron Bullet
“Influence of Small Arms Bullet Construction on Terminal Ballistics,” http://hsrlab.gatech.edu/AUTODYN/papers/paper162.pdf
McCall, Benjamin, “Q & A: Neutron Star Densities,” University of Illinois, http://van.physics.illinois.edu/qa/listing.php?id=16748
colophon
The body of this text was set Adobe Caslon Pro,
a Caslon variant designed by Carol Twombly
in 1990 based on Caslon’s specimen pages.
The section headings and question titles
were set in Univers, a realist sans serif
designed by Adrian Frutiger in 1954.
The questions were set in Glypha,
a square serif typeface designed
by Adrian Frutiger in 1977.
About the Author
RANDALL MUNROE, a former NASA roboticist, is the creator of the webcomic xkcd and the author of xkcd: volume 0. The International Astronomical Union recently named an asteroid after him; asteroid 4942 Munroe is big enough to cause a mass extinction if it ever hits a planet like Earth. He lives in Cambridge, Massachusetts.