Sharks on an Ideal Plane

There gets to a point when writing a PhD chapter, when you are on your third gin and tonic for the evening, that one should turn one’s attention outwardly. I’d like very much to share thoughts about my research but the very first thing they teach you in PhD school is that no-one else is interested in your topic, by virtue of being so obscure that it bears no relevance to the lives of others.

Instead I’ll do some calculations.

It seems to me rather odd, in this age of missing planes and controversial shark attacks, that interested parties (airlines and environmentalists, etc) frequently employ statistics to reinforce the fact that these events are exceptionally rare. And yes they are, by-and-large, though perhaps the most spectacular evidence that all is not what it seems, lies in the massive differences of the massive orders of magnitude in such material. And if one person is fit to recognise improper uses of statistics it is I, largely through my own severe transgressions.

Sharkplane

Had I used the right shark, I could have called this picture ‘Tiger Airways’ and been appropriate on so many levels.

Earlier this year I came across a promotional poster actually pitting plane crashes and sharks against each other – in favour of sharks I believe (something to the order of hundreds/thousands times more likely to crash than be consumed), which piqued my interest as these are two of my more intimate* fears, and also as I touched upon with that shark-toaster comparison a while ago, I realised that there are far, far, far, far too many factors in plane-shark relations to effectively compare them.

So let’s compare them.

* By intimate I mean that the number of dreams I’ve had involving planes and plane crashes are literally equal. I think become so accustomed I’d be super-demure if I was involved in an actual fiery descent. And also I’ve had a youthful encounter with a carpet shark in the wild and watched Jaws a little early.

Probability of death in an air accident if you never fly and permanently reside in a bomb shelter or other secure underground complex: Approximately 0

Probability of death via shark attack if you never go in or near any sizeable body of water, nor be near a shark in transit, nor otherwise encounter a shark: Approximately 0

Probability to ensure a plane accident (1): Assuming consecutive 1 hour flights you’d need 114.077 years according to some calculations. Given there are a handful of verified people who have lived past that age, you could potentially spend your life working towards that particular goal.

Probability to ensure a shark encounter (1): Assuming 1 million life-threatening sharks (according to my last ‘study’) each with a 5km blood detection range (78.54km^2) equally spaced, makes for a 78 537 816 km squared area of ocean currently under shark-veillance; meaning 23.42% of the world’s oceans are currently detectable by sharks. Totally inaccurate, but let’s go with it. Assuming a cruising speed of 8km/hour in straight lines, it would take our imaginary shark formation 19.635 hours to leisurely cover an entirely new 23.42%, and 84 hours to complete detecting all the earth’s oceans. So if you were adrift in the ocean, basically in the time for an equally-spaced shark to ‘certainly’ detect you (3.5 days) you’d be dying from, ironically, thirst.

We're going to need a bigger boa. :D

We’re going to need a bigger boa. 😀

So in fanciful summary, both planes crashes and shark attacks are something you could (I guesstimate) live to reasonably expect, but only towards the very end of your life in each situation. However, if you took to human shark-baiting in convenient instalments, it would become much more attainable, and there is probably a strong correlation between amount of human-shark numbers/proximity and attacks, whereas flights are more quantitative and can only take finite passengers (one hopes). Anyway, the moral is that both these situations could conceivably become either a statistical certainty OR a statistical impossibility, depending on person, country, airline choices, frequency, stupidity, rugged determination, weather, preferred swimming times, etc, etc, etc.

So don’t.