Key to the Universe

""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.

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