Read The Second Book of General Ignorance Online
Authors: John Lloyd,John Mitchinson
The Second Book of General Ignorance (14 page)
Not with a ripcord any more.
The traditional way of opening a parachute was to pull a handle attached to a stainless steel cable known as a ripcord.
Since the 1980s, pilot chutes, packed into a pocket in the parachute harness, have replaced ripcords. The pilot chute is much smaller than the main parachute – about a metre or 3 feet in diameter – and is usually released by the jumper pulling it out of its pocket and throwing it into the air. The sudden jerk as the pilot chute inflates removes the release pin for the main chute, which then opens. This is much safer than ripcords, as there is less chance of jamming.
Modern parachute canopies aren’t shaped like jellyfish any more, either. They are rectangular and made of a double layer of parallel tubular cells, a bit like an airbed. The back and sides of each cell are closed, but open at the front. As the tubes fill with air, the canopy forms a wedge, similar to the shape of a hang-glider. And, just as with hang-gliders, parachutes can be steered. The control cords also allow the jumper to slow down or speed up the rate of descent.
If the main parachute fails, there is a second or ‘reserve’ parachute to open and, even if the jump causes a loss of consciousness, there is an AAD, or Automatic Activation Device, which automatically releases the reserve parachute at about 230 metres (750 feet). The fatality rate for parachute jumps is one in 100,000, but almost none of these are caused by faulty equipment. Most result from reckless manoeuvres or from landing too fast; changes in wind conditions; or ‘canopy collisions’, where two parachutes get entangled.
Modern parachutists descend at about 40 kilometres per hour (25 miles per hour). In freefall, a body’s terminal velocity – where air resistance prevents it from falling any faster – is about 200 kilometres per hour (125 miles per hour). In normal atmospheric pressure, and with an uncontrolled posture, it takes about 573 metres (1,880 feet) or 14 seconds to reach this speed.
At higher altitudes, where the air is much less dense, a faster fall is possible. In 1960 US air force pilot Joseph
Kittenger leapt from a balloon at 31,333 metres (102,800 feet) and reached a speed of 988 kilometres per hour (613 miles per hour), close to the speed of sound. Despite continuing to dive head first, he began to spin rapidly and blacked out, coming round when his chute opened automatically around 1.6 kilometres (a mile) above the ground. He is now helping skydiver Felix Baumgartner prepare to break his fifty-year-old record. Baumgartner plans to dive from a balloon at 36,500 metres (120,000 feet or 23 miles). He aims to reach a speed of 1,110 kilometres per hour (690 miles per hour). This will make him the first person to break the sound barrier outside an aircraft. No one knows what the physical effects of supersonic speed will be on a human body.
Leonardo da Vinci is often credited with inventing the idea of a parachute, but the concept predates his famous 1485 drawing. An anonymous manuscript from a decade earlier shows a man wearing rather comical Italian dress and a nonchalant expression, holding on to a cone-shaped canopy. One can only hope it was never tested: it was much too small to slow his descent at all.
STEPHEN
I believe, Pam, that you felt some erotic feelings towards
your instructor. Is that correct?PAM AYRES
I did. I took a shine to the instructor. I think that’s why
I jumped out the aircraft, really,’cause I wanted to impress him.JOHNNY VEGAS
I often do that. If I like a woman, I jump out the
window. Just to show ’em I really care.
It’s not because you might burn your fingers.
A
meteorite
is an object that has fallen to Earth from space.
Meteors
, or ‘shooting stars’, are objects passing through the Earth’s atmosphere. Hundreds of tons of meteors bombard the Earth every day, but most of them are smaller than a grain of sand and burn up on entry.
Both words come from the Greek for celestial phenomena,
ta meteora
, which translates literally as ‘things suspended high up’. In films and comics, meteorites are hot – they hiss and sizzle as they land in the snow. In reality, they’re usually cold: some are even covered in frost.
This is because space is extremely cold. Although the friction of entering the atmosphere heats meteorites up, it also slows them down. They can take several minutes to fall to the ground: quite long enough for them to lose all the heat their outer surface has temporarily gained.
Meteorites are either stony or metallic – metallic ones ring like a bell when struck with another piece of metal. Most of them are as old as the Earth itself. A few are found immediately after their fall, many have lain in the ground for tens of thousands of years before being discovered. You are most unlikely to come across one. In the whole of the USA between 1807 and 2009, only 1,530 verified examples were found – that’s fewer than eight a year. Actually seeing a meteorite falling, and then finding it, is even rarer. In the same period, it only happened 202 times – by coincidence, exactly once a year. The latest edition of the Natural History Museum’s
Catalogue of Meteorites
, published since 1847 and listing every known meteorite, records just twenty-four as ever being found anywhere in the British Isles. Meteorite experts get hundreds of calls from the public every year: they rarely turn out to be the real thing.
The reason for not touching one is that you may contaminate any organic matter it might carry. If you do find a fresh one, you should put it in a sealed plastic bag (without touching it) and send it to your nearest research group.
The ‘Bolton Meteorite’ was found in the backyard of a house in the high street of the Lancashire town in 1928. It caused great excitement, which was rather dampened by the verdict of the British Museum in London – that it wasn’t a meteorite at all, just a piece of burnt coal. Even so, it’s still on display at the Bolton Museum.
When the first Europeans came to northern Greenland, they were amazed to find the local Inughuit, or polar Inuit, people using metal knives, despite having no idea how to either mine or smelt metal. They had chipped iron flakes off a meteorite using volcanic stones, and set them into handles made of walrus tusks.
The meteorite was one of three that were the centrepieces of their religion. They were 4.5 billion years old and the largest weighed 36 tons. In 1897, the American explorer Admiral Robert E. Peary stole them, selling all three to the American Museum of Natural History in New York for $40,000.
STEPHEN
Around 50,000 meteorites larger than 20 grams fall from
space to Earth every year. But more have been found on which
continent than any other?RICH HALL
Antarctica.STEPHEN
Antarctica, yes.ALAN
Bit tough on the penguins really, isn’t it.PHILL JUPITUS
That’s why they always stand up, because there’s
less of a surface area.
It’s got nothing to do with cannonballs.
The phrase ‘cold enough to freeze the balls off a brass monkey’ is often said to refer to a metallic grid with circular holes in it, set under a pyramid of cannonballs on a ship’s deck to keep it stable. When this ‘brass monkey’ got cold enough, the metal contracted and the cannonballs all popped out.
In fact, the phrase means exactly what it says; the fake nautical euphemism is an attempt to make its rude humour more acceptable.
First of all, it doesn’t make any sense to stack piles of cannonballs on the deck of a pitching warship. And they weren’t: they were kept in long thin racks running between the gunports, with a single hole for each cannonball.
Second, these frames were called ‘shot-racks’ or ‘shot garlands’ and they were made of wood, not brass.
Third, for one of these imaginary ‘brass monkeys’ to con tract even 1 millimetre (0.3 inch) more than the iron cannonballs it was supposed to hold, the temperature would have to drop to –66 °C, 8 degrees colder than ever recorded in Europe.
Fourth, naval slang from the days of sail abounds in expressions that involve the word monkey, but the phrase ‘brass monkey’ is nowhere among them.
The Sailors Word Book of
1867
, the comprehensive dictionary of nautical terms compiled by the naval surveyor and astronomer Admiral W. H. Smyth (1788–1865), records monkey-block, monkey-boat, monkey-tail, monkey-jacket, monkey-spars, powder-monkey and monkey-pump (an illegal device for illegally sucking rum through a hole drilled in the cask). The only entry under brass reads: ‘BRASS. Impudent assurance.’
Fifth, according to Dr Stewart Murray, a professional metallurgist and Chief Executive of the London Bullion
Market Association, the difference in thermal contraction between brass and iron in such a situation is ‘absolutely tiny’, even at extreme temperatures, and ‘far too insignificant to have that kind of effect’.
‘Cold enough to freeze the balls off a brass monkey’ began life demurely as ‘cold enough to freeze the tail off a brass monkey’. It was first recorded in mid-nineteenth-century America and variants of it were used as often about extremes of heat as they were of cold. In Herman Melville’s novel
Omoo
(1850) one of the characters remarks that ‘It was ’ot enough to melt the nose h’off a brass monkey’.
Michael Quinion of www.worldwidewords.org suggests that the ‘monkey’ element originated in the popular nineteenth-century brass ornaments featuring the three monkeys that ‘hear no evil, see no evil, speak no evil’.
Clustering round a roaring Dickensian fire on a winter’s night, far inland from the sea, what better reminder could there be of how cold it is outside than the line of cheeky brass monkeys sitting on the mantelpiece?
You will struggle to find any snow or ice at all. You are most likely to bump into a large, malodorous beast known as the musk ox.
Peary Land is a mountainous peninsula extending from northern Greenland into the Arctic Ocean. It is the most northerly ice-free land on Earth. Lying 725 kilometres (450 miles) south of the North Pole and covering 57,000 square kilometres (22,000 square miles), it is bigger than Denmark.
It was first mapped in 1892 by the American explorer Robert E. Peary (1856–1920), who modestly named it after himself.
Dry enough to be counted as a desert, it is frost-free for three months in the summer, when temperatures often exceed 10 °C and can reach 18 °C. Winter is very cold, though: usually around –30 °C. Rain is rare and the very occasional snow that falls is so dry it simply drifts away and never forms into ice.
Vegetation covers only 5 per cent of the total area but thirty-three species of flowering plant have been recorded and this is enough to support the population of 1,500 musk oxen.
Despite their names, musk oxen are actually large, shaggy members of the goat family. They get their name from the intense smell the males secrete from glands under their eyes when aroused. Musk-ox hair can grow almost 60 centimetres (2 feet) long, covering them in a thick-fringed pelt that reaches to the ground. This keeps them warm but it also means they aren’t particularly fast on their feet.
Their defensive strategy is to form a circle around the younger and more vulnerable members of the herd and try to stare down any predators.
Historically, this worked well with Arctic wolves and bears, but wasn’t much use against men with rifles. At the turn of the twentieth century, they had been hunted to the brink of extinction. They are now a protected species and the Arctic population has recovered to 150,000 individuals.
Musk oxen are ancient. They evolved over 600,000 years ago and were contemporaries with the woolly mammoth, the giant ground sloth and the sabre-tooth tiger. They are one of very few large mammal species to have survived the last Ice Age, which reached its peak 20,000 years ago.
It’s never too cold: at least, not in this world.
Anyone who lives in a country where it snows in winter will have heard people say, ‘It’s been trying to snow all day, but it’s just too cold!’
This is never the case. Snow has been recorded in Alaska at below –41 °C and there are reports of snow falling at the South Pole at an incredible –50 °C. Flakes have even been made in the lab at –80 °C, which is as cold as the coldest parts of Antarctica ever get. It is true that, at temperatures below –33 °C very little ordinary ‘snow’ is produced. Instead, individual ice crystals fall to Earth in a phenomenon known as ‘diamond dust’. These are so cold they can’t clump together to form the familiar snowflakes, but they are still snow.
The reason why it doesn’t always snow when it’s cold is that, in northern Europe, very cold weather is usually associated with high pressure. In an area of high pressure, there is little air movement, so the cold air gradually sinks, warming as it falls. This means that any water in the air evaporates completely rather than forming into clouds. In summer, this produces hot, clear weather. In winter, it allows heat from the ground to rise upwards, because there is no insulating cloud layer. This lowers the ground temperature, particularly at night, when there is no sun to warm it. Although it’s bitterly cold, there are no clouds to produce snow.