Authors: Bill Bryson
At first, it was suggested that this route to self-organisation might be followed by all complex self-adaptive systems. That was far too optimistic: it is just one of many types of self-organisation. Yet, the nice feature of these insights is that they show that it is still possible to make important discoveries by observing the everyday things of life and asking the right questions, just like the founding Fellows of the Royal Society 350 years ago. You don’t always have to have satellites, accelerators and overwhelming computer power. Sometimes complexity can be simple too.
1
This civil and theological background can be traced in the study in J.D. Barrow,
The World Within the World
(Oxford, OUP, 1988), of the development of the concept of laws of Nature in ancient societies.
2
In practice, the process of improving central theories of physics usually involves a process of replacing a theory by a deeper and broader version that contains the original as a special, or limiting, case. Thus, Newton’s theory of gravity has been superseded by Einstein’s theory of general relativity but not replaced by it in some type of scientific ‘revolution’. Einstein’s theory becomes the same as Newton’s when we confine attention to weak gravitational forces and to motions at speeds much less than that of light. Similarly, another limiting process recovers Newtonian mechanics from quantum mechanics. This is why, regardless of the results of our search for the ‘ultimate’ theory of gravity, structural engineers and sports scientists will still be using Newton’s laws in a thousand years’ time.
3
Four fundamental forces are known, of which the weakest is gravitation. There might exist other, far weaker, forces of Nature. Although too weak for us to measure (perhaps ever), their existence may be necessary to fix the logical necessity of that single theory of everything. Without any means to check on their existence, we would always be missing a crucial piece of the cosmic jigsaw puzzle; see J.D. Barrow,
New Theories of Everything: The quest for ultimate explanation
(Oxford, OUP, 2007) and B. Greene,
The Elegant Universe
(London, Jonathan Cape, 1999).
4
These mathematical discoveries launched an intensive search for the underlying M theory. But so far it has not been found. Other possibilities have emerged along the way, with the arguments of Lisa Randall and Raman Sundrum that the three-dimensional space that we inhabit may be thought of as the surface of a higher-dimensional space in which the strong, weak, and electromagnetic forces act only in that three-dimensional surface while the force of gravity reaches out into all the other dimensions as well. This is why it is so much weaker than the other three forces of Nature in this picture; see L. Randall,
Warped Passages: Unravelling the Universe’s Hidden Dimensions
(London, Penguin, 2006).
5
For a discussion of the status of the constants of Nature and evidence for their possible time variation, see J.D. Barrow,
The Constants of Nature
(London, Cape, 2002).
6
This is one of the lessons learned from the anthropic principles.
7
Einstein used the elegant fact that tensor equations maintain the same form under any transformation of the coordinates used to express them. This is called the principle of general covariance.
8
T he velocities of the molecules will also tend to attain a particular probability distribution of values, depending only on the temperature, called the Maxwell–Boltzmann distribution after many collisions, regardless of their initial values.
9
This is clearly very important for computing the behaviour of chaotic systems. Many systems posesess a s
hadowing
property that ensures that computer calculations of long-term averages can be very accurate, even in the presence of rounding errors and other small inaccuracies introduced by the computer’s ability to store only a finite number of decimal places. These ‘round-off’ errors move the solution being calculated on to another nearby solution trajectory. Many chaotic systems have the property that these nearby behaviours end up visiting all the same places as the original solution and it doesn’t make any difference in the long-run that you have been shifted from one to the other. For example, when considering molecules moving inside a container, you would set about calculating the pressure exerted on the walls by considering a molecule travelling from one side to the other and rebounding off a wall. In practice, a particular molecule might never make it across the container to hit the wall because it runs into other molecules. However, it gets replaced by another molecule that is behaving in the same way as it would have done had it continued on its way unperturbed.
10
R.M. May, ‘Simple Mathematical Models with Very Complicated Dynamics’,
Nature,
261 (1976), 45. Later, this work would be rigorously formalised and generalised by Mitchell Feigenbaum in his classic paper ‘The Universal Metric Properties of Nonlinear Transformations’, published in
J. Stat. Phys.,
21 (1979), 669 and then explained in simpler terms for a wider audience in the magazine
Los Alamos Science
1, 4 (1980).
11
Closer examination of the details of the fall of sand has revealed that avalanches of asymmetrically shaped grains, like rice, produce the critical scale-independent behaviour even more accurately because the rice grains always tumble rather than slide.
12
P. Bak,
How Nature Works
(New York, Copernicus, 1996).
Oliver Morton is a writer, currently working for
The Economist.
He is the author of
Mapping Mars
and
Eating the Sun,
and currently at work on a book about geo-engineering.
T
HE PICTURES OF THE
E
ARTH FROM SPACE BROUGHT HOME BY
T
HE APOLLO ASTRONAUTS TRIGGERED A NEW AWARENESS OF OUR PLANETARY HOME WHICH FED INTO NEW SCIENCE.
B
UT THE VIEW OF OUR PROBLEMS FROM ASTRONOMICAL DISTANCE IS AN ODD ONE, AS
O
LIVER
M
ORTON EXPLAINS.
‘I know we’re not the first to discover this,’ Gene Cernan radioed back from about 29,000 kilometres, ‘but we’d like to confirm, from the crew of
America,
that the world is round.’ Apollo 17 had been thrown up into the night sky over Florida five hours before, but for most of that time the command module
America
and its lunar module
Challenger
had been in low orbit. Only now, having been kicked off to the Moon by the last stage of their Saturn V booster, were the astronauts far enough away to see the planet as a whole.
Challenger
was to land on the edge of the Moon’s face as seen from the Earth, rather than near the centre, as previous missions had done, and this meant that Apollo 17 was the first of its kind to head off more or less straight into the Sun, thus allowing Cernan and his crew an unprecedented look back at the shadowless face of the noon-time Earth.
Their photographic record of that view, it is often claimed, is the most reproduced photographic image in history; given that it is free to use, beautiful and moving, the claim seems not unlikely. Taken from the window of the
America
without the benefit of a viewfinder, the almost-perfectly circular image is dominated by blue oceans and white cloud, an obscuring and captivating pattern which makes the picture clearly and immediately something other than a map. This is a body in space, three-dimensional, a highlight glinting off the ocean, the features at the edge distant and foreshortened. But in this picture, unlike those taken from the Moon itself, there is no doubting what the bewitching body is. The mass of Africa, though centred in a way no traditional map maker would think of, is unmistakable.
When, in late 1946, George Orwell wondered in an essay how he would convince a committed sceptic that the Earth was spherical,
1
he concluded with some reluctance that he would be unable to do better than appeal to the authority of astronomers and to the utility of charts that astronomical observations made possible. Twenty-five years on, the figure of the planet became a matter of direct observation for the select few, and of photographic fact for the rest. There was no longer any need to rely on the
astronomer’s authority; by looking at the Apollo pictures one could in effect become an astronomer.
The ability to see the Earth as an astronomer would another planet marked a fundamental shift, the long-term effects of which we still cannot gauge. It has provided valuable new perspectives and treasure troves of data. But no image can reveal everything; and every revelation obscures something. For all that it is an image of the whole, the vision of the Earth from space is necessarily partial. By leaving things out, it makes the Earth too easy to objectify, too easy to hold at a distance, too easy to idealise. It needs to be offset by a deeper sense of the world as it is felt from the inside, and as it extends out of view into past and future. Because of the changes we are putting the planet through, we need as many ways of looking at and thinking about it as we can find. We need ways to see it as a history, a system, and a set of choices, not just a thing of beauty – one which, from our astronomical perspective, we seem already to have left. There are other ways to see the beauty of the world than in the rear-view mirror of progress.
This needs to be stressed in part because the astronomer’s gaze is a peculiarly powerful, seductive thing; it is not just thin air that brings dizziness to mountain-top observatories. Its charms are those of photography in general; a form of seeing more removed from direct experience, and frequently from obvious meaning, than any other, its subjects unavailable to any cross-examining form of scrutiny. Like photography, astronomy looks, takes joy in looking – but can do no more than keep looking.
In their desire to see and see again, astronomers are particularly well served. Many of the objects of their gaze are eternal and predictable, travelling into our future according to knowable rules. The universe reveals itself in rhythm and return. This is one reason why the visions of astronomy have often stood as an emblem for all the other precise, disinterested but forward-looking observations of science.
Spectacular gains have been made by turning the astronomer’s gaze on the Earth. The wetness of clouds, the strength of winds, subtle shifts in the shape of the sea’s surface, the thickness of smogs, the colours of the savannah: all are now available on a worldwide scale. Not only can everything be seen: in some of these images, like that icon from Apollo 17, we seem to see everything at once, the Earth entire. It was this completeness which, in the 1970s, gave such images a key role in both the inception and reception of James Lovelock’s ideas about Gaia, the self-regulating Earth system – ideas presented, in the subtitle of his first book, as ‘A New Look at Life on Earth’.
2
Such images made clear what Arthur C. Clarke had suggested years before: the archetype for space travel was the
Odyssey,
an adventure completed only in its moment of return. The view that little ship of Apollo brought back gave new reality to the notion, first voiced by Adlai Stevenson in 1965, of ‘Spaceship Earth’: like the smaller ships, the larger one was a prerequisite for its crew’s survival, isolated, fragile. The image of the living Earth as seen from space became a rallying point for environmental activism, an ever-present rebuke to those who would deny the environment’s fragility, the finitude of its resources, the limits that it must surely impose on us. It turned the primary concern of the ‘space age’ from the outward urge of a few to the common heritage of the many.
In ‘Globes and Spheres: The Topology of Environmentalism’,
3
the anthropologist Tim Ingold voiced an elegant dissent to the way that heritage was represented by those pictures. The global environmental
movement represented by that objectified, photographed Earth, he argued, was an oxymoron; the environment of a globe is what lies outside it, not what lies within. Thinking about the environment ‘from the outside’ was a contradictory pursuit that showed a rationalist, map-making mentality taken to its ultimate extreme. To give the planet as a whole precedence over everything it contains, he thought, hid the realities of life as it is lived, and was thus inimical to a deeper-rooted form of environmental awareness. ‘The notion of the global environment,’ he wrote, ‘far from marking humanity’s reintegration into the world, signals the culmination of a process of separation.’
The Earth does, as it happens, have an environment in the surrounding sense, a space environment that is both nurturing (a magnetosphere that keeps cosmic rays at bay), a little alarming (near-Earth asteroids, which have in the past caused spectacular calamities and even mass extinctions) and increasingly besmirched (600,000 pieces of space junk and counting). Recognising this cosmic connectedness may in time help to expand our notion of the world we live in, providing new perspectives of its own. But that is not Ingold’s point; his point is that to see the earthly environment as something out there and separate is to misunderstand what an environment is.
To agree with Ingold is no to say that everything must be local first and last, nor to deny that there are environmental problems on a planetary scale. It is to say that they are not the planet’s problems. They are ours. The drawback of space-age iconography is that it has made the Earth itself the focus of environmental action, the thing at risk, the mother to be celebrated on a consecrated Earth Day. This way of speaking about the planet in peril, of invoking a need to ‘save the Earth’, suggests either that the needs of people and the needs of the planet are directly opposed – or, at best, that human needs can be reduced to planetary needs.