A molecule is simply two or more atoms working together in a more or less stable arrangement: add two atoms of hydrogen to one atom of oxygen and you have a molecule of water.
At sea level, at a temperature of 0 degrees Celcius, one cubic centimetre of air (that is, the space about the size of sugar cube) will contain about 45 billion billion molecules. And they are in every single cubic centimetre you see around you.
Above all, atoms are tiny – very tiny indeed. Half a million of them lined up shoulder to shoulder could hide behind a human hair. On such a scale an individual atom is essentially impossible to imagine, but we can of course try.
Neutrons and protons occupy the atom’s nucleus. The nucleus of an atom is tiny – only one-millionth of a billionth of the volume of the atom – but fantastically dense, since it contains virtually all the atoms mass. As Cropper has put it, if an atom were expanded to the size of a cathedral, the nucleus would be only about the size of a fly – but a fly that is many thousands of times heavier than the cathedral.
It is still a fairly astounding notion to consider that atoms are mostly empty space, and that the solidity we experience around us is mostly an illusion. When two objects come together in the real world – billiard balls are most often used for illustration – they don’t actually strike each other. ‘Rather,’ as Timothy Ferris explains, ‘the negatively charged fields of the two balls repel each other…[W]ere it not for their electrical charges they could, like galaxies, pass right through each other unscathed.’ When you sit in a chair, you are not actually sitting there, but levitating above it a a height of one angstrom (a hundred millionth of a centimetre), your electrons and the its electrons implacably opposed to any closer intimacy.
Perhaps the most arresting of quantum improbabilities is the idea, arising from Wolfgang Pauli’s Exclusion Principle of 1925, that certain parts of subatomic particles, even when separated by the most considerable distances, can instantly ‘know’ what the other is doing. Particles have a quality known as spin and, according to quantum theory, the moment you determine the spin of one particle, its sister particle, no matter how distant away, will immediately begin spinning in the opposite direction and at the same rate.
It is as if, in the word of the science writer Lawrence Joseph, you had two identical pool balls, one in Ohio and the other in Fiji, and that the instant you sent one spinning the other would immediately spin in a contrary direction at precisely the same speed. Remarkably, this phenomenon was proved in 1997 when physicists at the University of Geneva sent photons seven miles in opposite directions and demonstrated that interfering with one provoked an instantaneous response in the other.
(particle accelerators) can whip particles into such a state of liveliness that a single electron can do 47,000 laps around a 7-kilometre tunnel in under a second.
‘Strange as it may seem,’ wrote Richard Feynmann, ‘we understand the distribution of matter in the interior of the sun far better than we understand the interior of the earth.’
The distance from the surface of the Earth to the middle is about 6,370 kilometres, which isn’t very far.
One or two South African gold mines reach a depth of over 3 kilometres, but most mines on Earth go no more than about 400 metres beneath the surface. If the planet were an apple, we wouldn’t yet have broken through the skin.
The last supervolcano eruption on Earth was at Toba, in northern Sumatra, 74,000 years ago. …The event, it is thought, may have carried humans right to the brink of extinction, reducing the global population to no more than a few thousand individuals. That would mean that all modern humans arose from a very small population base, which would explain our lack of genetic diversity.
In 1978, an astrophysicist named Michael Hart made some calculations and concluded that Earth would have been uninhabitable had it been just 1 per cent further from or 5 per cent closer to the Sun. That’s not much, and in fact it wasn’t enough. The figures have since been refined and made a little more generous – 5 per cent nearer and 15 per cent further are though to be accurate assessments for our zone of habitability – but that is still a narrow belt.
A fluffy summer cumulus several hundred metres to a side may contain no more than 100-150 litres of water – ‘about enough to fill a bath tub’, as James Trefil has noted. You can get some since of the immateriality quality of clouds by strolling through fog – which is, after all, nothing more than a cloud that lacks the will to fly.
Only about 0.035 per cent of the Earth’s fresh water is floating around above us at any moment.
If you are in good health and averagely diligent about hygiene, you will have a herd of about one trillion bacteria grazing on your fleshy skin – about a hundred thousand of them on every square centimetre of skin.
Every human body consists of about ten quadrillion cells, but is host to about a hundred quadrillion bacterial cells. From a bacteria’s point of view, of course, we are a rather small part of them.
Indeed, according to Woese, if you totalled up all the biomass of the planet - every living thing, plants included – microbes would account for at least 80 per cent of all there is, perhaps more. The world belongs to the very small – and it has done for a very long time.
Perhaps an even more effective way of grasping our extreme recentness as part of this 4.5-billion-year-old picture is to stretch your arms to their fullest extent and imagine the width as the entire history of the Earth. On this scale, according to John McPhee in Basin and the Range, …’and in a single stroke with a medium-grained nail file you could eradicate human history.’
It’s a somewhat galling notion to reflect that every inch of your surface is deceased. If you are an average-sized adult you are lugging around over 2 kilograms of dead skin, of which several billion tiny fragments are sloughed off each day.
…almost every one of them (cells) holds two yards of densely compacted DNA, and you begin to appreciate just how much of this stuff you carry around with you. If all your DNA were woven into a single fine strand, there would be enough of it to stretch from the Earth to the Moon and back, not once or twice but again and again. Altogether, according to one calculation, you may have as much as 20 million kilometres of DNA bundled up inside of you.
A bolt of lightening travels at 435,000 kilometres an hour…
At any one moment 1,800 thunderstorms are in progress around the globe – some 40,000 a day.
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