by John Lloyd
The idea that the Moon was made of cheese seems to date from the sixteenth century. The first citation, from John Heywood’s Proverbs (1564), says ‘the moon is made of greene chees’. It is thought that in this context, the word ‘greene’ means ‘new’, rather than having a green colour, as young cheeses would often have a more mottled appearance; much like the cratered Moon.
Does the Earth go round the Moon or the Moon
round the Earth?
Both. They go round one another.
The two bodies orbit a common centre of gravity located about 1,600 km (1,000 miles) below the surface of the Earth, so the Earth makes three different rotations: around its own axis, around the Sun and around this point.
Confused? Even Newton claimed that thinking about the motion of the Moon gave him a headache.
How many moons does the Earth have?
At least seven.
Certainly the Moon (or Luna, as astronomers call it) is the only celestial body to observe a strict orbit of the Earth. But there are now six other ‘Near-Earth’ Asteroids (NEAs) which do follow the Earth around the Sun, despite being invisible to the naked eye.
The first of these ‘co-orbitals’ to be identified was Cruithne (pronounced Cru-een-ya, and named after Britain’s earliest recorded Celtic tribe), a three-mile-wide satellite, discovered in 1997. It has an odd horseshoe-shaped orbit.
Since then, six more have been identified: the snappily named 2000 PH5, 2000 WN10, 2002 AA29, 2003 YN107 and 2004 GU9.
Are they really moons? Many astronomers would say no, but they are certainly more than just run-of-the-mill asteroids. Like Earth they take roughly a year to orbit the Sun (think of two cars going round a race track at the same speed but in different lanes) and do, occasionally, come close enough to exert a very slight gravitational influence.
So whether you call them pseudo-moons, quasi-satellites, or companion asteroids, they are worth watching, not least because some or all of them may one day settle down into a more regular orbital pattern.
STEPHEN What man-made artefacts can be seen from the moon with the naked eye?
RICH Which moon are we talkin’ about?
How many planets are there in the solar system?
Eight. If you still think there’s nine you’ve obviously been living in a parallel solar system.
On 24 August 2006, the General Assembly of the International Astronomical Union finally agreed its long overdue definition of a ‘planet’. Planets must fulfil three criteria: they have to orbit the sun, have enough mass to be spherical, and to have ‘cleared the neighbourhood’ around their orbit. Pluto only managed the first two, so was demoted to the status of ‘dwarf planet’.
It’s not perfect – some astronomers argue that neither Earth, Jupiter or Neptune have cleared their orbits either – but it does resolve the anomalous position of Pluto.
Even the planet’s discoverers in 1930 weren’t fully convinced of its status, referring to it as a trans-Neptunian object or TNO– something on the edge of the solar system, beyond Neptune.
Pluto is much smaller than all the other planets, a fifth the mass of the Moon and smaller than seven of the moons of other planets. It isn’t much larger than its own main moon, Charon (two more, smaller, Plutonian moons, Nix and Hydra, were discovered in 2005). Its orbit is eccentric and on a different plane from the other planets, and its composition is completely different.
The four innermost planets are medium-sized and rocky; the next four are gas giants. Pluto is a tiny ball of ice – one of at least 60,000 small, comet-like objects forming the Kuiper belt right on the edge of the solar system.
All these planetoid objects (including asteroids, TNOs and a host of other subclassifications) are known collectively as minor planets. There are 371,670 of them already registered, around 5,000 new ones are discovered each month and it is estimated there may be almost 2 million such bodies with diameters of over a kilometre. Most are much too small to be considered as planets but twelve of them give Pluto a run for its money.
One of them, discovered in 2005 as 2003 UB313 and now named Eris, is actually larger than Pluto. Others, such as Sedna, Orcus, and Quaoar, aren’t far off.
Now Pluto, Eris and Ceres – the largest body in the asteroid belt between Mars and Jupiter – have been officially adopted as the first three dwarf planets.
This change isn’t unprecedented. Ceres, like Pluto, was considered a planet from its discovery in 1801 until the 1850s when it was downgraded to an asteroid.
The American Dialect Society voted ‘to pluto’, meaning ‘to demote or devalue someone or something’ their Word of the Year for 2006.
ALAN [Pluto is] really, really big, and it goes around the sun!
BILL Yes, well, so does my aunt Wilma.
STEPHEN Yes, well, it’s not really big at all. It’s tiny.
ALAN Well, that’s why it took so long to find it; don’t be hard on it because it’s small …
How would you fly through an asteroid belt?
Keep an eye open, but it’s really unlikely you’ll collide with anything.
Despite what you may have seen in bad sci-fi films, asteroid belts are typically quite desolate places. Busy when compared with the rest of space, but desolate nonetheless.
Generally, the gap between large asteroids (ones which could do significant damage to a space ship) is about two million kilometres (nearly 1¼ million miles).
Although there are some clusters called ‘families’ which have been recently formed from a larger body, it would not be too difficult to manoeuvre around an asteroid belt. In fact, if you picked a random course, you’d be lucky to see a single asteroid.
If you did, you might like to give it a name.
These days the International Astronomical Union has a fifteen-person Committee for Small-Body Nomenclature to control the naming of the ever-expanding roll-call of minor planets. It’s not an entirely serious business, as these recent examples show:
(15887) Daveclark, (14965) Bonk, (18932) Robinhood, (69961) Millosevich, (2829) Bobhope, (7328) Seanconnery, (5762) Wanke, (453) Tea, (3904) Honda, (17627) Humptydumpty, (9941) Iguanodon, (9949) Brontosaurus, (9778) Isabelallende, (4479) Charlieparker, (9007) James Bond, (39415) Janeausten, (11548) Jerrylewis, (19367) Pink Floyd, (5878) Charlene, (6042) Cheshirecat, (4735) Gary, (3742) Sunshine, (17458) Dick, (1629) Pecker and (821) Fanny
Smith, Jones, Brown and Robinson are all official names of asteroids; so are Bikki, Bus, Bok, Lick, Kwee, Hippo, MrSpock, Roddenberry and Swissair.
Eccentricity in planet-naming isn’t new. Pluto was named in 1930 by an eleven-year-old Oxford schoolgirl called Venetia Burney, whose grandfather passed on her breakfast-time suggestion to his good friend Herbert Hall Turner, the Oxford Professor of Astronomy.
Perhaps 2003 UB313 will after all be named Rupert, Douglas Adams’s name for the tenth planet in The Hitch-hiker’s Guide to the Galaxy. Stranger things have happened. The day before Adams suddenly died in 2001, the asteroid (18610) Arthurdent was first named. And now he has one of his very own: (25924) Douglasadams.
What’s in an atom?
Mostly nothing. The vast majority of an atom is empty space.
To get it into perspective, imagine an atom the size of an international sports stadium. The electrons are right up at the top of the stands, each smaller than a pin-head. The nucleus of the atom is on the centre spot of the pitch, and is about the size of a pea.
For many centuries, atoms, which were entirely theoretical, were thought to be the smallest possible units of matter, hence the word, which means ‘not-cut’ in Greek.
Then, in 1897, the electron was discovered, followed in 1911 by the nucleus. The atom was split and the neutron discovered in 1932.
This was by no means the end of the matter. The positively charged protons and uncharged neutrons in the nucleus are made of still smaller elements.
These even tinier units called quarks are given names like ‘strangeness’ and ‘charm’ and come not in diff
erent shapes and sizes but ‘flavours’.
The distant satellites of the nucleus, the negatively charged electrons, are so odd they are no longer even called that but ‘Probability Density Charges’.
By the 1950s, so many new subatomic particles (over 100) had been found that it was becoming an embarrassment. Whatever matter might be, no one seemed able to get to the bottom of it.
Enrico Fermi, the Italian-born physicist who won the Nobel Physics Prize in 1938 for his work on atomic reactors, was quoted as saying: ‘If I could remember the names of all these particles, I’d be a botanist.’
Since Fermi’s time, scientists have settled on the number of subatomic particles inside an atom at twenty-four. This best guess is known as the Standard Model, giving the impression that we have a pretty good idea what’s what.
The universe in general, as far as we can tell, is as underpopulated as the atom itself. Space, on average, contains just a couple of atoms per cubic metre.
Occasionally, gravity pulls them together into stars, planets and giraffes, which seems equally extraordinary.
STEPHEN Now, if the proton were the size of a drawing pin, the electron would be the size of a pinhead, and it would be one kilometre away.
JEREMY HARDY Yeah, and if I were to put a pineapple on my head, I’d look like Carmen Miranda, but I don’t!
What’s the main ingredient of air?
a) Oxygen
b) Carbon dioxide
c) Hydrogen
d) Nitrogen
Nitrogen. As every twelve-year-old knows, it accounts for 78 per cent of the air.
Less than 21 per cent of air is oxygen. Only three hundredths of 1 per cent of the air is carbon dioxide.
The high percentage of nitrogen in the air is a result of volcanic eruptions during the formation of the Earth. Vast amounts of it were released into the atmosphere. Being heavier than hydrogen or helium it has stayed closer to the surface of the planet.
A person weighing 76 kg contains almost 1 kg of nitrogen.
Nitre is the old name for saltpetre, or potassium nitrate. A key ingredient in gunpowder, it is also used to cure meat, as a preservative in ice cream, and the anaesthetic in toothpaste for sensitive teeth.
For several hundred years, the richest source of saltpetre was the organic mulch that had seeped into the earth floor of human houses. In 1601, the unscrupulous activities of the ‘Saltpeetermen’ were raised in Parliament. They would break into houses and even churches, dig up the floors and sell the earth for gunpowder.
The word nitrogen means ‘soda-forming’ in Greek.
Beer cans with pressure-sensitive ‘widgets’ contain nitrogen, not carbon dioxide. The smaller nitrogen bubbles make a smoother, creamier head.
The only other significant gas in air is argon (1 per cent).
It was discovered by William John Strutt, Lord Rayleigh, who was also the first man to work out why the sky is blue.
Where would you go for a lungful of ozone?
Don’t bother going to the seaside.
The nineteenth-century cult of healthy sea air was based on a fundamental misunderstanding. The bracing, salty tang has nothing to do with ozone, an unstable and dangerous gas.
Ozone was discovered in 1840 by the German chemist Christian Schönbein. Investigating the peculiar odour that lingers around electrical equipment he traced it to a gas, O3, which he named after the Greek for ‘to smell’ (ozein).
Ozone or ‘heavy air’ found favour with medical scientists still in the grip of the ‘miasma’ theory of disease, where ill health was thought to spring from bad smells. Ozone, they thought, was just the thing to clear the lungs of harmful ‘effluvia’ and the seaside was just the place to get it.
A whole industry grew up around ‘ozone cures’ and ‘ozone hotels’ (there are still some carrying the name in Australasia). As late as 1939, Blackpool was still boasting ‘the healthiest ozone in Britain’.
Nowadays, we know that the seaside doesn’t smell of ozone – it smells of rotting seaweed. There’s no evidence this smell does you good or harm (it’s mostly compounds of sulphur). It may simply trigger positive associations in your brain, linking back to happy childhood holidays.
As for ozone, the fumes from your car’s exhaust (when combined with sunlight) create far more ozone than anything on the beach. If you really want a lungful, the best thing would be to clamp your mouth round an exhaust pipe. This is emphatically not recommended. Apart from doing irreparable damage to your lungs, you could burn your lips.
Ozone is used to make bleach and to kill bacteria in drinking water as a less noxious alternative to chlorine. It is also generated by high-voltage electrical equipment such as televisions and photocopiers.
Some trees, such as oaks and willows, release ozone which can poison nearby vegetation.
The shrinking ozone layer, which protects the planet from dangerous ultra-violet radiation, would be fatal if inhaled. It is 24 km (15 miles) above the Earth’s surface and smells faintly of geraniums.
What colour is nicotine?
If you said ‘yellow’ or ’brown’ go to the bottom of the class. Nicotine is colourless.
Nicotine is found in all plants of the Solanaceae, or nightshade family, which includes tobacco, deadly nightshade, tomatoes, potatoes, aubergines and chilli peppers. In theory, cigarettes can be made out of potato or tomato leaves and some programmes designed to help people stop smoking also advise giving up potatoes and tomatoes in order to eliminate low-level nicotine intake completely.
Cauliflower and coca leaves, from which cocaine is made, also contain nicotine.
In small doses, the nicotine compound solanine that is present in all these plants produces feelings of pleasure by increasing levels of the hormone dopamine in the brain. It’s why tobacco is more addictive than either cocaine or heroin, but it’s also why we sometimes find ourselves craving chips or pizza. Solanine generates adrenaline, leading to higher blood pressure, a faster heart rate, and enhanced sugar levels in the blood, producing a combination of euphoria and alertness.
In large doses, however, solanine and nicotine are as deadly as the nightshade whose relative they are. Tomato leaves can be made into a potent insecticide. The nicotine in a single cigarette, if taken direct into the bloodstream, would be fatal. Eating one cigarette could make you severely ill and swallowing a packet of ten would definitely kill you. In 1976, the Department of Health urged pregnant mothers to wear rubber gloves when peeling potatoes and more than a kilogram (2.2 lb) of potatoes eaten at a single sitting would be certain death.
Fortunately for smokers, most of the nicotine in a cigarette is burned before it ever gets to the lungs. The other good news is, it doesn’t stain your fingers or your teeth or the ceiling of the pub. It’s not only colourless but soluble in water, so it comes off when you wash your hands. The stain on a smoker’s fingers is caused by tar.
The scientific name for tobacco is Nicotiana tabacum. The name of the plant and the word nicotine derive from Jean Nicot (1530–1604), French ambassador to Lisbon, and the man who first introduced tobacco to France in 1560. He originally promoted it as a medicine, believing it healed wounds and cured cancers, and sent some, in the form of snuff, to Catherine de Medici, Queen of France. She was so impressed when it stopped her migraine that she decreed it should be called herba regina, the ‘queen’s herb’.
Pure nicotine is one the most powerful poisons known: one and a half times as toxic as strychnine and three times as toxic as arsenic. Arsenic is also present in tobacco, along with 4,000 other chemicals, 200 of which are carcinogenic, including formaldehyde (used to preserve dead bodies), acetone (the main ingredient of nail-polish remover), cadmium (used in batteries) and hydrogen cyanide (the gas in Nazi death camps).
What speed does light travel at?
That depends.
It’s often said that the speed of light is constant, but it isn’t. Only in a vacuum does light reach its maximum speed of nearly 300,000 km per second (186,282 mi
les per second).
In any other medium, the speed of light varies considerably, always being slower than the figure everyone knows. Through diamonds, for example, it goes less than half as fast: about 130,000 km per second, or 80,000 miles per second.
Until recently, the slowest recorded speed of light (through sodium at –272 °C) was just over 60 kph (38 mph): slower than a bicycle.
In 2000, the same team (at Harvard University) managed to bring light to a complete standstill by shining it into a bec (Bose-Einstein condensate) of the element rubidium.
Rubidium was discovered by Robert Bunsen (1811–99) who didn’t invent the Bunsen burner which is named after him.
Astoundingly, light is invisible.
You can’t see the light itself, you can only see what it bumps into. A beam of light in a vacuum, shining at right angles to the observer, cannot be seen.
Although this is very odd, it’s quite logical. If light itself was visible, it would form a kind of fog between your eyes and everything in front of you.
Darkness is equally strange. It’s not there but you can’t see through it.
How do moths feel about flames?
They’re not attracted to them. They are disorientated by them.
Apart from the odd forest fire, artificial light sources have been in existence for an extremely short time in comparison with the age of the relationship between moths and the Sun and Moon. Many insects use these light sources to navigate by day and night.