Key to the Universe

After years of confusion,scientists all over the world have reached a very exciting stage in their research into the basic ingredients of all matter. They say that the protons and neutrons  at the heart of atoms are made up of elusive little things called quarks.In the diagrams on these pages Alec Nesbitt,the producer of Thursday's programme discusses quarks.Thirty - five year old Dr Stephen Hawking FRS,a scientist in the tradition of Einstein,is working to link these discoveries with his own research into "black holes" - despite grave physical handicaps.Overleaf he talks to John Hall.

Key to the Universe

The Hunting of the quark

Key to the Universe

Adding red,blue and green light makes white. There are believed to be three differently "coloured" quarks in the proton -so no colours are visible.

""When I use a word," said Lewis Carroll's Humpty Dumpty,"it means just what I choose it to mean." Today's high energy physicists have followed Alice to a land where familiar words like "colour", "strangeness" and "charm" take on new meanings;and to a new looking glass-world of opposites:"anti colours","anti strangeness" and "anti charm" - in short,anti matter.
 Early in the present century it was discovered that every atom had a nucleus of protons and neutrons with electrons buzzing around it.Then people began to ask : is the proton itself made up other particles? Gradually, a picture emerged of the proton as an assembly of much smaller objects, which were dubbed "quarks". Each proton, it seemed, was composed of three quarks, glued together in some way.
 Bigger and bigger machines smashed protons to pieces and physicists searched among the flying debris for clues to the proton's composition.
All sorts of unexplained particles emerged,often to exist for less than a million-millionth of a second before creating fantastic firework displays of more familiar breakdown products. Eventually many of these new particles were explained as combinations of quarks with different properties, and these had to have names.
Two were called "up" and "down";and an ingredient of some of the more exotic particles became "strangeness".Many theories of how these fitted together were tried out.The most promising required a fourth quality - called "charm"
*. The three-quark theory predicted that certain particles would break up in particular ways that simply did not happen. A fourth quark could explain these non-events. But the new theory also made a prediction - that charm (whatever it might be) would prove to exist.That set off the biggest hunt of recent years.
 For a while, even as the "Key to the Universe" programme was being made, the search appeared in vain.

Theorists began casting around for alternative explanations.For a month or two  of 1976 charm seemed about to meet the fate of Humpty Dumpty himself.But then,within weeks,the whole picture changed dramatically,and already Nobel Prizes have been handed out to the scientists who started the chain of discovery.
The theorists needed the quarks in the proton to be different in other ways,too,and they chose colours.Colour one quark "red",the next "blue" and the third "green". Like a colour television,if you add red, blue and green light you get white, which is just as it should be, for the experimenters see no overall colour in the proton; yet it must be there, the theorists insisted, because some such quality is needed to provide the force that holds quarks together.
 So how about the fourth quark - coloured lilac on our key? Physicists are split in their opinions about it. They're drawing up their lines for the next confrontation about that - again, it's the sort of fight that has Nobel Prizes for the victors.
* It's perhaps worth noting that Hamilton required to add a fourth quantity to his number triples in order to get Quaternions to work.

A few weeks ago members of the Relativity Group of the Department of Applied Maths and Theoretical Physics at Cambridge sat down to commemorate the 61st anniversary of the most important scientific finding of the century - Einstein's general theory of relativity.They celebrated by upgrading the cheese and pickle menu of their regular weekly meetings to include wine and pate,they entertained guests from the Institute of Astronomy,and they whiled away the luncheon hour by swapping thoughts on the agreed topic of "the energy-momentum skeleton".
 Among the group was a man whose work,if it can be brought to a successful conclusion,will be celebrated as an intellectual feat approaching Einstein's.
 When he spoke everyone paid attention; they had to, because Stephen Hawking is scarcely capable of speech.His theorising promises to answer key questions about the nature of everything in the universe, but when he wants to communicate to a man sitting next to him at a table,then both of them must make an effort of concentration to draw order from the chaos of his own voice.
 A rare degenerative neuromotor disease which appeared when Hawking was a 21 year-old graduate has wasted his body for 13 years,leaving him a perilously frail creature confined to a wheelchair.
 But one thing about him which strikes everyone more forcibly than his physical decay is the unremitting drive of his intellect and his spirit.And if that sounds like a picture of grim fortitude at bay,perish the image; Hawking is a witty,gregarious and forthright character who is simply more bloody-minded than most people when it comes to wrestling with problems,whether they are the biggest problems of cosmology or those of his own musculature.
 His office at the former book store which houses the maths and physics theorists is as bland as accommodation should be for men whose minds are set on events light years distant.The only non-functional adornments appear to be a blown up computer print-out forming a portrait of Einstein and a bumper sticker which announces: "Black holes are out of sight".
Black holes have been the subject of Hawking's special attention as a theoretical astronomer and whenever scientists speak of them they usually speak in the same breath of Hawking or his findings. For his work in this area he was made at the age of 32 one of the youngest fellows of the Royal Society; and the terms "black hole", "gravitational collapse" or "highly condensed matter" invariably appear on the citations accompanying the embarrassingly frequent academic awards.

Steve Hawking

 Whatever may be argued about the properties of black holes, they are indisputably out of sight.That is perhaps their most salient feature.Already they have become part of the science fiction canon as regions of ultimate peril for the unwary cosmonaut,near which he may find time accelerating at an appalling rate,and in which the tidal effect of gravity will spaghettify him before translating him,mercifully,into a beam of particles.They are especially treacherous because the space traveller can't actually see where they are - for,by definition,so great is the gravitational force in these regions that not even light can escape its effect.
According to classical black hole theory,most of this science fiction lore is accurate.But Hawking caused something of a stir a couple of years ago by announcing that in fact black holes emit radiation;that they have a temperature which rises incredibly the smaller they become;and that ultimately,when they have shrunk until they are smaller than a million millionth of a centimetre across,they will explode with the force of a million megaton bomb.
The people who did the stirring when Hawking announced this calculation were not elderly ladies nervous of loud noises,they were scientists whose theories did not allow for  black holes permitting anything to escape from their clutches. For this is,of course,all theoretical work. In the fields of astronomy and particle physics, unlike most other areas of science, theoreticians make predictions about the way things might be expected to happen,and observers keep watch,either on outer space or on sub-atomic particles,to see if events substantiate the theories.
"Although a Frenchman speculated about the existence of black holes as long ago as 1798,many people did not believe they existed as recently as the 60s," Hawking says."But now there is strong evidence that there is a black hole orbiting a normal star in a binary star system called Cygnus X-1.

Antimatter Tracks

At Fermilab,near Chicago,an international team led by Professor Burhop of University College London,set up a stack of photographic emulsion in the world's most powerful beam of neutrinos (shown here as a white line).From the heavy debris of a collision with nuclear matter a faint dotted track emerges.Nearly a hundredth of an inch long,it was made by a particle that survived for less than a million millionth of a second (shown here piercing the heart).From the manner of its creation and decay the scientists put strong odds on its containing a charmed quark.

I think it is now generally accepted that this is, in fact a black hole.
"There are probably two ways in which they are formed. When a star of a certain size burns up  all its nuclear fuel it collapses in on itself until it becomes so small and dense that its light cannot escape its gravity.
 The other way they might be formed would be in the early days of the universe when some hot and dense regions became so compressed that they collapsed to form small black holes. A black hole containing the mass of, say, a mountain would be no bigger than an elementary particle, many times smaller than an atom. There is no observational evidence that these small black holes exist, but astronomers are looking for the gamma ray bursts which would be given off when they explode. Such an explosion is not likely to do us any harm. There will probably be no more than one small black hole per solar system,and the nearest one to us is not likely to be closer than the orbit of Pluto."
But can they do us any good?
It has been suggested that if a black hole smaller than an atom could in some way be towed into the Earth's orbit we might fire into it all our waste materials and at the same time harness the million megawatts of radiation which the black hole would be emitting. Hawking answers that he is not hoping to make a fortune by taking out a patent.
"Any application would belong to the realms of science fiction. Of course, science fiction does come true - you have only to look at the writing of Jules Verne to know that.

 But my work will probably be useful only in the long term - in helping our understanding of how the universe originated, what its structure is, and what is our place in it.
It's possible that it might have practical applications not yet seen, but I could not predict what they might be."

Hawking's most important early work was done in conjunction with an Oxford theorist called Roger Penrose, was concerned with the nature of the space-time singularities which occur at the centre of black holes. These are points where the condensation of matter has reached such a degree that an infinite density of material is contained in zero volume,and where the known laws of physics break down.
A singularity is also thought to have been the source of the "big bang" which started our universe 10,000 million years or more ago, and from which came all of its particles and forces. Theorems about these singularities, which can never be seen, may nevertheless tell us fundamental things about everything in the universe today.Is it then possible that work of this kind may provide us with a definitive rule-book to the universe?
Hawking is not sure.
"There may not be a final answer, a so-called key to the universe.We may simply learn a little bit more and a little bit more and never get a complete answer. By the year 2000 we may have worked out all the basic laws, but on the other hand we might have reached a new level of complexity that we cannot yet know about. In a way I think it would be a pity if there were some sort of final answer to all our questions. Men enjoy finding out new things,and it wouldn't leave much of a life for subsequent generations of enquirers."
But some kind of pattern may be emerging from what have traditionally been considered entirely separate fundamental schemes of 20th century physics:

Quantum mechanics and relativity theory.  Quantum Theory deals with the behaviour of matter at the sub-atomic level, while relativity is concerned with space, time and the gravitational attraction between planets, stars and galaxies.
Thursday's programme describes the elaborate techniques used to identify and catalogue the components of Nature at each level - the quark particles currently thought to be the ultimate constituents of matter,the neutrinos flying around at the speed of light and affecting virtually nothing they hit; pulsars, quasars and possible black holes in deep space.
Attempting a synthesis of information from the two schemes - the sub-microscopic and the cosmic - is one of the most intractable problems of physics. Stephen Hawking has already begun to make the connection and people working in the field expect that he will be the one to manage it, finally. By common consensus it would be an awesome achievement. "A tremendous conceptual advance comparable to Einstein's connection of gravity and inertia in general relativity," according to Dr Dennis Sciama, Senior Research Fellow at All Souls, Oxford, and formerly Hawking's teacher.
 How close, then, is Hawking to making the leap of relating quantum theory and relativity? Sitting at supper with his wife Jane and his children Robert aged nine, and Lucy, six, he moves easily from the problems of cosmology to those of a model railway layout,and back again.


He allows that his work may be an advance in the right direction,but adds that he can't guarantee that it will be solved.
But he says it sheepishly, with a twinkle in his eye,and his wife interprets this as false modesty: "Come on, Stephen, I can tell from the way you say it that you think you can do it."
The chances are that if he thinks he can, Hawking will do it. His life is a story of determined effort of will. When he talks about the disability which confines him to a wheelchair there is not the slightest note of regret in his sentiments.
"When you're disabled the thing to do is put all of your effort into those areas where you are not handicapped,and develop them. I am very lucky because for the sort of work I do all I need is my brain. If I had been involved in any sort of experimental work my career would have been interrupted, because I can't even hold a pen to write, let alone a test-tube.I can't do a long calculation on paper,of course,so I have to do maths in my head. This makes me look for an overall pattern,and perhaps I can take a short cut to an answer which I would never have seen if I had been working on paper. Because I can't do things that normal people have to do I have a lot more time to sit and think, and it's interesting to speculate if being like this has actually been an advantage to me as a theoretical physicist.
"Another effect I am sure of, is that being disabled and not knowing how long I would live reduced my expectations so much that I appreciate all the good things in my life.I know they're a bonus I had no right to expect.I think,in fact I'm probably happier than if I had been well."





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