FEEDBACK has been invaded by elephants. The proximate cause is our plea for help in calculating how many actual elephants would be required to achieve the 8000 elephant-standing-on-a-Mini-Cooper units of pressure used by UK newspaper The Daily Telegraph. Should we take into account Newton鈥檚 law of gravity and the reduced weight of the elephants toward the top of a 28-kilometre pile (2 June)? We are obliged to produce an exceptionally elephantine issue鈥� a pachyderm special, no less.
What does it mean, Peder Aspen wonders, that is 鈥�0% fat free鈥�? Is it all fat? Or any amount of fat the manufacturers like? Number theorists 鈥� help!
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MANY readers responded to the plea. William Bains writes that 鈥渁s a rough approximation, the weight would be 0.43 per cent lower, if corrected for gravity, than the sea-level weight of 8 kilopachyderms鈥�. That, rather disappointingly, looks right. The topmost elephant, 6399 kilometres from the centre of the Earth, will weigh about 0.87 per cent less than one at sea level, nominally 6371 km from the centre.
William also points out something that we realised only when we read our piece in print: one way for the topmost elephant to achieve orbit is for it to be in geosynchronous orbit, 42,000 km or 12 mega-elephants up. Alternatively, as William notes, 鈥渢he elephant at the bottom could run very, very fast鈥�.
ATTEMPTING to confound the issue further, John Anderson points out that 鈥渢he elephants at the top of the stack are going round the centre of the Earth faster: they will therefore, thanks to Einstein, weigh very slightly more due to their increased speed鈥�. 鈥淏y inspection鈥�, as arm-waving lecturers may say, we dismiss this effect as rather small 鈥� subject, as ever, to correction by readers.
VALIANTLY but vainly trying to change the subject, Martin Pook suggests that we could have avoided the question by adopting a geometry demonstrated, in a scale model employing sheep, in the animation series popular on British TV. 鈥淥ne stands on the Mini Cooper, two on his (or her) back, side by side with linked legs鈥︹�� and so forth. Quick modelling in a spreadsheet shows that a pyramid 126 beasts high 鈥� a mere 440-odd metres 鈥� would contain 8001 elephants 鈥� or sheep, or blue whales with linked flippers, depending on the scale of your model.
ELEPHANTS continue, meanwhile, to provide rich inspiration for coiners of imaginative units. Robin Stratford sends a puzzling image that implies another elephantine unit of pressure. The label from a Wolf Garten lawn cutter depicts a foot (presumably human) in a Wellington boot pushing on the top edge of the blade. Beneath is an elephant foot about to stab itself on the top corner of the blade. Ouch.
THE dinosaur Tyrannosaurus rex, , 鈥渉ad the most powerful bite of any creature that lived. Researchers鈥� described it as 鈥榚quivalent to the weight of a medium-sized elephant鈥�.鈥� 鈥淎t last,鈥� says Adam Colligan, 鈥渟ome precision! We know what kind of elephant we鈥檙e dealing with.鈥�
VIRTUAL elephants now appear to readers seeing odd units. Reading in New 杏吧原创 that 鈥渁 hammock made from graphene would be strong enough to swing a cat weighing a kilogram鈥� (Instant Expert, 5 May), Lee Seldon wants to know, 鈥渉ow does that convert to 鈥榚lephant weighing a kilogram鈥�?鈥�
And the UK Department of Energy鈥檚 informs us that 鈥渁 terawatt hour is鈥� equivalent to leaving on a small hairdryer in every home in Britain, continuously, for 1.6 days鈥�. Bob Irving presumes that 鈥渢his is to dry off the elephants鈥�.
COSMOLOGISTS will not be left out. Liam O鈥橤rady reports popular astrophysicist Neil deGrasse Tyson noting : 鈥淚f you cram a herd of 50 million elephants into a thimble, you get the density of a Pulsar. I鈥檓 just saying.鈥�
THE 鈥済rammar鈥� of road-signs has long fascinated Feedback. Outside the US, it is in theory precise: things encircled in red are forbidden; those in red triangles are warned against; and those depicted in white on blue circles are compulsory, for example.
So what was Brendon Barker to make of the sign he saw in Namibia with an exclamation point in a red triangle over the word 鈥渆lephants鈥� and the injunction 鈥�80 km/h鈥�, in a red rectangular border? He thought, 鈥淚t must be hard for the calves to keep up.鈥�
Evidence that Feedback does in fact get out may be provided by our observation that in the UK words in a red rectangular border are directions to a military installation. What does this say about Namibia鈥檚 elephants?
FINALLY, Feedback resolves to spend the next few months not thinking about elephants. But we all know what happens when we make such promises. We are assiduously not thinking about nominative determinism, and not at all about the , via Stephen Mugford, that Australia鈥檚 entrant to the World Ploughing Championships, in Croatia in September, is Adrian Tilling.