Prof. Peter Norman Wilkinson
The University of Manchester
dr. h.c. UMK
Rector Magnificus, Prof. Radziminski, distinguished guests and all members of the University here today. I first want to offer my sincerest thanks the university – not only for awarding me the degree of doctor honoris causa, but also for this separate honour of inviting me to address you at this opening of the new academic year in Toruń
I want to talk to you about the importance of astronomy for humankind, about my own small contributions to it, and look ahead to the future, in which the Nicolas Copernicus University has a great opportunity.
I have visited Torun many times – first in 1986 with my wife Althea – who is also an astronomer. We came to visit Andrzej Kus – he and I had started a collaboration some years before when he stayed in Manchester for a year.
Change was in the air. We remember the gates of the Gdansk shipyard and the “Solidarity” Church. But we remember best the tremendous warmth of our reception by Andrzej and his wife Halina and others in the Toruń Observatory led by Professor Stan Gorgolewski. We were treated to some magnificent banquets in very small apartments – we never knew where that wonderful food and drink came from – and were wise enough not to ask!
Another memory is the opening of the 32-m telescope in Piwnice in 1994 and Professor Wihelmina Iwanowska , then over 90 years old, breaking the champagne bottle on the telescope and bowing before it – after all she had done so much to help it come into being !
Since then I have been back to Toruń many times. – and am delighted that Poland is back in Europe and that Toruń itself buzzes with vitality.
Toruń, of course, is forever linked with one of the most famous astronomers of all time. We all know a little of the religious, mythological and astrological beliefs which have been linked with the skies. For millennia the Sun and stars also have been used for navigation and for constructing calendars to capture the regularity of the year and to mark the times for planting and harvesting
By the way it’s very hard to construct a calendar based on the rotation rate of the Earth (the day); the orbital period of the Moon around the Earth (the “mo(o)nth”) and the orbital period of the Earth around the Sun (the year) – since none of these numbers are related ! Many different calendars have been constructed and it took until the time of Julius Caesar to get the length of the year correct to about 11 minutes. Over the next 1500 years this error added up to about 10 days and the seasons had slipped very obviously out of synchronism with the date. This was put right in 1582 by astronomers working for Pope Gregory XIII – we now take their labours, all depending on observations with the naked eye, completely for granted when we look up the date. Nowadays, of course, rather than the naked eye, we use giant telescopes to study the skies and we define our standard of time, not by the spin of the Earth, but by the much more accurate beat of atomic clocks.
Science now recognizes a profound link between the atomic world and the universe seen with our telescopes – I’ll return to this – but now step back 40 years from the revolution taking place in the Vatican to the more important revolution which had its birth in Toruń – I refer of course to De Revolutionibus Orbium Coelestium by Nicolas Copernicus – published just before his death in 1543. Incidentally about half of that first edition, estimated at 500 copies, is still in existence. The largest number, 44 copies, are in Germany where the book was published but in second place, with 42 copies, is the UK. The University of Manchester has two and last week I had the privilege of holding one of them in my hands!
Copernicus’s interpretation of the motions of the planets was based on aesthetics not physics. But his challenge to the old way of thinking – discarding the most obvious interpretation and seeking a more beautiful one – started a new train of human thought. Over the next century the gradual understanding of the beautiful physics experiment being conducted in the skies, free from the complications of friction which confused thinkers from Aristotle onwards, began the scientific revolution which has now completely transformed our way of life.
At the heart of all science is the “scientific method” – the most successful approach to systematic thinking that mankind has developed. At its most basic it starts with careful description of a phenomenon, which someone then formulates a theory or mechanism to explain . This theory – and this is most important – must then be tested by successfully predicting the results of new and different observations.
So scientific thinking is based on hard evidence. Copernicus’s more elegant picture was no better at accounting for the observed motions of the planets than Greek epicycles. But it implied that Venus should show phases like the Moon and appear to vary in size throughout the year. It is impossible to check these predictions with the naked eye but Galileo Galilei, using one of the first astronomical telescopes, was able to discern the expected size and phase changes to provide incontrovertible evidence that Copernicus was right.
More accurate measurements by Tycho Brahe, analysed by Johannes Kepler, revealed more subtle mathematical patterns of behaviour in the planetary motions than were available to Copernicus. They were explained by Isaac Newton’s Law of Universal Gravitation – this was mankind’ s first glimpse of the deep underlying order in the universe. Newton himself said that he had “only been able to see further than others because he was standing on the shoulders of giants” – Copernicus was one of them and the start of the scientific world can be traced back to his birth in Torun.
Scientific theories are open to attack from new data – but it took 350 years before Newton’s gravity was superseded after failing to predict the orbit of Mercury correctly. Einstein’s new theory of gravity – the General Theory of Relativity – solved the Mercury problem and famously predicted the correct bending of light rays as they passed close to the Sun. This was triumphantly confirmed during a solar eclipse in 1919 – and Einstein immediately became the first global scientific superstar. Astronomy had again been vital for verifying something fundamental about the physical world.
Ten years later Edwin Hubble in California announced the discovery of the expanding Universe. Some bold astronomers now began to “turn the clock of the universe backwards” and in the 1930s a picture emerged of the universe which, although now vast, was immensely denser and hotter in the past with its evolution described by Einstein’s equations. Perhaps ironically, given the history of Galileo’s persecution by the Vatican for supporting Copernicus, this radical idea – later to be called the “Big Bang” – was first proposed by a young Catholic priest, Abbé Georges Lemâitre in Louvain.
After the war dramatic new results began to pile in – with the new science of radio astronomy in the lead, thrust forward by the technical advances made in radar. In the 1950s radio astronomers showed that the number of radio sources was greater in the past than today – more evidence that the cosmos is far removed from the static, unchanging, place envisaged only a few decades before.
The 1960s when I, and many of the distinguished professors present today were students, was a particularly rich decade for discovery – again led by radio astronomy. It seemed as if every year brought something new and exciting. The predicted echo of the Big Bang, now called the Cosmic Microwave Background, was discovered by accident by two radio engineers working in Bell Labs on satellite communications. Quasars, the most luminous objects in the universe, were identified in a beautiful combination of radio and optical astronomy. The extraordinary energy they release is from matter heated up as it falls into a massive black hole one hundred million times the mass of the sun.
In 1968 pulsars were also stumbled upon, by radio astronomers in Cambridge. Pulsars are not black holes but spinning neutron stars in which the mass of the Sun is packed within a sphere whose diameter no bigger than Greater London and whose density is greater than that of an atomic nucleus !
Another discovery made around this time – the cosmic gamma ray bursters – also came about by accident. To monitor compliance with the 1963 Partial Test Ban Treaty the USA had launched a series of satellites. But instead of man-made nuclear explosions they detected flashes of gamma radiation of unknown origin. It took over 30 more years to solve the puzzle – the bursts come from the most violent events in the universe. Stars much more massive than the Sun end their lives in cataclysmic supernova explosions. They leave behind a black hole and shoot out intense beams of radiation which can be seen across the universe. A gamma ray burster in our own galaxy would be hazardous to life on Earth – and might have been the cause of at least one of the mass extinctions of life !
I have now mentioned the word “discovery” several times – but how do scientists make them? Most often it is by seeking out unexplored aspects of the natural world – with new technology allowing the collection of data with much better sensitivity, much better resolution in angle, distance , time, or frequency or any combination of these.
But the “human factor” is as important as new technology. I’ve mentioned how several major discoveries were serendipitous – lucky if you like – but, as a well-known golfer once said: “the harder I practice the luckier I get” or as Pasteur said “in the field of observation chance favours the prepared mind”. In other words people who made discoveries have often immersed themselves in their observations so that they can recognize an unexpected clue for what it’s worth. On the other hand one can simply be lucky enough to be “the right man at the right time and not to know too much” – not burdened by existing preconceptions.
There is no single prescription – but certainly the most reliable route to finding new phenomena is to combine technological advance with patience. The amount of “surprise” in a data set rises slowly as the set enlarges – in fact it was discovered in the early 1940s that the number of newly identified varieties of an animal species rises only as the logarithm of number of specimens you collect—we now know that this is a general truth of information theory.
In astronomy our animal collecting expeditions are new surveys of the sky – and for this we need specially-designed telescopes and instrumentation. I see a great opportunity to make completely new radio surveys to complement the new optical and infra-red ones that will be made with new ground-based and space-based telescopes in the next decade. That is why Professor Kus and I have proposed a new radio telescope for Poland with the lead to be taken by this university. 90 metres in diameter and of innovative design the telescope will be outfitted with the coming generation of “radio cameras” to sweep across the sky and carry out previously impossible surveys.
You might ask, why has radio astronomy had such a rich history of discovery with five Nobel Prizes awarded – far more than for any other type of astronomy? I’d like to think it was that radio astronomers are cleverer – but really it is because radio waves carry unique information about the universe. They are generated in many different ways – from the echo of the Big Bang to the surface of Sun – from the simplest element to complex organic molecules, from black holes and neutron stars. And they penetrate clouds of cosmic dust which often obscure the radiation in other wavebands. So it won’t surprise you that I think there is a lot more to come from radio telescopes!
I want now to describe a little of my own work and a few lessons I have learned.
In his book “Profiles of the Future” the British science fiction writer and futurologist Arthur C. Clarke stated: “When a distinguished but elderly scientist states that something is possible he is almost certainly right. When he states that something is impossible, he is very probably wrong.” Some of my most successful work was said to be impossible by Professor Martin Ryle, who was honoured by this university in the same year, 1974, in which he was awarded the Nobel Prize for Physics !
In the 1950s, at Jodrell Bank near Manchester, Professor Bernard Lovell had built the world’s first giant radio telescope 76m across. I was inspired to become a radio astronomer by this telescope. But while huge telescopes are very sensitive they cannot pick out much detail – the resolution of Lovell’s telescope is much worse than your eyes. To see more detail you would need to make it bigger – but then you run into limitations posed by wind and gravity and in fact no-one has built a fully steerable telescope with a diameter bigger than 100 metres.
Ryle got around this resolution limit by combining signals from an array of smaller telescopes spread out over several kilometres. In effect he found a way “synthesise” a large aperture without having to build all of it – and with his colleague Anthony Hewish he was awarded a Nobel Prize in 1974. Their best images revealed narrow jets of radio-emitting plasma pointing at the “parent” galaxy located towards the centre of the radio source. But the resolution of Ryle’s new synthesis telescopes was not enough to look deep inside the galaxy to see what was going on.
To increase the resolution meant increasing the separation of his telescopes – but there Ryle ran into his own problem. Just as fluctuations in the atmosphere makes the stars twinkle and produce blurred images in optical telescopes – the atmosphere also blurs the image produced by a radio synthesis telescopes because the signals from the telescopes separated by more than about 5 kilometres do not combine together properly. Ryle was convinced that this effect would fundamentally limit the resolution of his technique – but it was not long before he was proved wrong!
In 1974, after completing our PhD’s, my wife and I left Manchester for Caltech and I began working with Professor Marshall Cohen and another post-doctoral fellow, now a Caltech Professor, Anthony Readhead. The Caltech group were early pioneers in the technique called Very Long Baseline Interferometry (VLBI). This was the ultimate extension of Ryle’s ideas for synthesizing a large aperture – but here the telescopes are not physically connected. The signals are recorded on magnetic media together with ultra-accurate ticks from atomic clocks. This allows the data from telescopes in different countries, across continents, to be synchronized, perhaps weeks later.
As soon as this tricky technique was made to work in the 1960s it revealed very intense regions of radio emission in the centres of quasars. But the corrupting effect of the atmosphere prevented the pioneers from making detailed images. Readhead and I thought that this was an exciting problem and, undaunted by the opinions of the Nobel Prize winner, began to work on it.
The details of our solution are too technical for a talk like this – but along the way I learned another lesson. Not all superb ideas are recognized at the time – as Copernicus found out ! In our case the essential trick to get around the atmosphere’s corrupting effect had been invented by another Manchester radio astronomer 20 years earlier, but largely forgotten. We used this idea and combined it with some ideas of our own, to produce the first radio image of a quasar nucleus.
The ability to make much higher resolution images changed the whole field. They revealed that the central radio sources also had thin “jets” emerging on one side – and that these jets appeared to move outwards faster-than-light! It was soon realized that Einstein’s speed limit was not violated – the jet material is moving just below the speed of light, its speed appears magnified when it is pointing towards us. The nuclear jet is often aligned with the jet seen on much larger scales – implying that something in the middle of the quasar must not only be a powerful source of energy to accelerate material to nearly the speed of light, it must also have a long term memory. We now believe that the jets are formed close to a massive black hole whose spin keeps its axis pointing in the same direction for millions of years.
Further improvements to the new technique proved vital for the success of Manchester’s MERLIN array which stretches across England. The superb radio images we produced had a great impact on the development other large radio telescope arrays and made it credible for me to propose the Square Kilometre Array with 200 times the collecting area of Lovell’s telescope in Manchester. The SKA is now a world-wide development programme involving astronomers and engineers in many tens of institutes.
VLBI itself has now developed into a series of continental and global networks. Toruń has a fine 32-metre radio telescope which is a vital component in the European VLBI Network – and it routinely takes part in many global VLBI observations. Because the resolution of VLBI is so much higher than any other technique in astronomy, it has brought new insights into many astronomical phenomena.
Astronomy has always been a science without frontiers – even in the dark days of the war astronomers were sharing their results across Europe – the VLBI networks, which depend on international cooperation and whose whole is much greater than the sum of its parts, are a wonderful example of this.
The international VLBI Networks are also an example of the fact that astronomy has become a “big science” dominated by large teams working with expensive observing facilities on the ground and in space. The vast amounts of data generated by some facilities have produced a new type of astronomer. These “data miners” just use a computer to access the public data archives and to carry out observational projects not considered when the data were originally collected. Half the scientific papers from the Hubble Space Telescope have been produced in this way.
The biggest archive is from the Sloan Digital Sky Survey which contains data on millions of galaxies and quasars and hundreds of millions of stars. It’s freely available on the web. Systematic trawling of this archive by a team of volunteers has recently uncovered a new class of galaxies. Even more surprising a new object, whose physical nature remains unclear, has been discovered by a Dutch school teacher.
While the big science approach is unavoidable it carries with it a danger. Large facilities do not provide good “hands-on” training grounds for students – it’s too risky to give an important part of the design, be it hardware or software, to an inexperienced person. Luckily I was brought up in a different era and a different, university observatory, culture. As students we knew our equipment backwards and could trouble-shoot it.
So we need to develop instruments in the universities, both to open up new areas into which future big facilities can grow and to provide learning opportunities for students. They are the ones who will design the telescopes of the future. Professor Kus and I are now engaged in a university-university project with a Manchester-built multi-pixel “radio camera” installed on the 32-m telescope in Piwnice. New science is being done and young scientists in both Torun and Manchester are gaining experience of making complex equipment work and developing new ways to analyse the data. The lessons are being fed into our thinking for the proposed new 90-metre telescope.
Given the limited number of jobs in academia it’s more likely, however, that astronomy students will eventually take their advanced skills into the wider commercial world. The UK government is demanding a greater economic impact from its funding of research – and radio astronomy techniques are close to those used in many practical applications. I myself am becoming interested in an extension of Ryle’s synthesis technique for security screening in airports – but that’s a subject for another day.
It brings me, however, to one of the standard questions astronomers are often asked – wouldn’t it be better to use the money spent on more deserving causes – to lessen human suffering for example ? My first answer is that the public is fascinated by astronomy – as a science it’s second only to medically-related stories in its media coverage. I have several times been interviewed on Polish TV with the 32-m radio telescope in the background. More practically there is no doubt that the scale and strangeness of the cosmos inspires students to enter science courses. And the cutting-edge technology developed for and by astronomers has given us the charge-coupled devices used in all our cameras, the wireless networking used in all our laptops and image reconstruction techniques used in medicine and law enforcement. There are many more examples.
So accepting that the public is happy for astronomy to continue – where is it going?
The Universe is quite literally the final frontier – here we can look for and find new phenomena that are completely impossible to find in Earth-based laboratories. And just thinking about it raises some of the deepest questions in science.
We have discovered some great truths – that the universe does not extend infinitely far back in time, something dramatic happened 13.7 billion years ago – that the overall geometry of the universe obeys the Euclid’s rules. But most of the universe’s matter and energy – which Einstein told us are really the same – are in a form which our telescopes can’t detect directly. “Normal matter”, which makes up stars, planets and us, only contributes about 5%; “Dark Matter”, which doesn’t emit light or radio waves, and “Dark Energy”, which has antigravity properties, make up the rest. So 95% of the contents of the universe is currently a mystery!
In the coming decades the pace of progress will continue – the results from the Large Hadron Collider coupled with new observations of the Cosmic Microwave Background will tell us more about the ultimate particle accelerator, the Big Bang itself. New observations of distant supernovae and of the three dimensional distribution of galaxies will tell us more about the fate of the Universe. Currently it looks like the expansion is accelerating and, if that continues, within a few trillion years our galaxy will be all alone in a dark universe – a rather depressing prospect even now.
But have we got the physics right? It’s amazing that the same physical laws seem to apply all over the observable Universe and as far back in time as we have yet probed. But the great cornerstones of modern physics, Quantum Mechanics and General Relativity, are incompatible and will eventually be superseded by a deeper theory which combines them both. The current favourite is something called string theory – which I don’t pretend to understand. But we are told that string theory offers a potential answer to another profound cosmic conundrum – the “fine tuning” problem.
The laws of physics and the values of the fundamental physical constants are “just right“ so as to enable conscious life, us, to emerge – on the other hand if they were not so homo sapiens would not be here to ask the question – so this is a somewhat circular argument. Nevertheless the apparent “fine-tuning” of the physical constants is intriguing.
One suggestion is that this situation arises purely by chance. String theorists propose that ours may be just one of 10500 universes – an unimaginably large number – in which the physical laws and the physical constants are all different. We just happen to live in the one which allows consciousness to develop.
In his new book the famous British cosmologist Steven Hawking writes that there is now “no need for God” – all can be explained by string theory. The trouble is that as yet there is not a shred of evidence that string theory is right ! But even if scientists of the future find that evidence, the reasons for such mathematical order at the heart of the universe will surely remain mysterious.
As in Thomas Aquinas’s proofs of the existence of God, it all comes down to the First Cause. Why is there anything? Humans have been pondering this ultimate question for thousands of years – but to my mind science has not provided the merest hint of an answer. Our brains evolved to hunt and gather more efficiently on the plains of Africa – so perhaps some profoundly abstract answers will always lie out of our reach.
Are there any other beings in the universe who have made more progress? The search for life on other worlds will be one of the other main themes of 21st century astronomy. Finding life, even primitive life, would profoundly affect the human psyche – knocking away the last of our sense of specialness – a process started by Copernicus. Already almost 500 planets have been found around other stars – but they are invariably too large or too close to their star to support life as we know it. But now a new generation of space-based telescopes is capable of finding planets like the Earth – and the first candidates are emerging. Watch out for many announcements in the next few years. Amazingly there’s a good chance of probing the atmospheres of these planets for signs of oxygen or ozone – clear-cut evidence of plant life.
So far, despite searches with radio telescopes, we have no evidence for “intelligent” signals. But we could be too primitive to see them. Like peoples in the Amazon and Borneo who were blissfully unaware of signals from satellites flooding their jungle clearings – could it be that civilizations a million and more years older and more advanced than ours communicate by ways completely unknown to us ? Of course.
To bring us back down to earth I want to end with a quote a UK Government Minister who recently said :
“ …scientific enquiry is a public good. It helps to define the quality of our civilisation, and embeds logical scientific thinking into the decision-making of government, businesses and households. Superstition and irrational prejudice about the natural world are rarely far from the surface and scientists help inoculate society against them”
Fine words – but beware of politicians – in this speech the Minister also signaled that major cuts in the UK science budget are coming !.
So, at this opening of the new academic year, I offer the Rector and his colleagues my best wishes in their onerous task of guiding and developing the University in difficult financial times. I am sure that under your leadership the University is run in a “business-like” fashion – but I do hope you and the Senate will strive to avoid the tendency, emerging in UK universities, to operate “like a business”. Intellectual endeavour does not prosper if run like a production line.
To the academic staff and students in whatever discipline I would echo the words of the poet Robert Frost – in your intellectual endeavours dare to “take the road less travelled” – take some risks, look ahead, challenge old ideas, seek new ways of thinking and never willingly accept second best. But also remember the words of the inventor Thomas Alva Edison – “genius is 1 percent inspiration 99 percent perspiration”- nothing comes unless you put in the hard work!
Thank you again for the honour of addressing you today