"In the spring of 1974, about two years before the Viking spacecraft landed on Mars, I was at a meeting in England sponsored by the Royal Society of London to explore the question of how to search for extraterrestrial life. During a coffee break I noticed a much larger meeting was being held in an adjacent hall, which out of curiosity I entered. I soon realized I was witnessing an ancient rite, the investiture of new fellows into the Royal Society, one of the most ancient scholarly organizations on the planet. In the front row a young man in a wheelchair was, very slowly, signing his name in a book that bore on its earliest pages the signature of Isaac Newton. When at last he finished, there was a stirring ovation. Stephen Hawking was a legend even then."Carl Sagan
The current Lucasian Professor is a leader in theoretical physics and cosmology whose work has been mainly concerned with topics such as time and the beginning of the universe.1 He has been searching for a theory that will unify all of physics.2 Stephen Hawking (b. 1942) notes an interesting coincidence, his birthday, January 8, 1942, is three hundred years to the day that Galileo died.
Note: Professor Hawking officially retired on October 1, 2009.
Professor Hawking has an illness called amyotrophic lateral sclerosis or motor neuron disease, also known as Lou Gehrig's disease. It is a disease in which the voluntary muscles become useless over time until an early death is reached. Professor Hawking has lived longer than anyone with the disease and much longer than was expected when it was first diagnosed. He does not wish to focus on this problem, but rather on his work. He has not allowed the disease to stop his work in theoretical physics, which as he notes, requires thinking more than physical activity. The fact that he is confined to a wheelchair and can no longer speak, is not something that has curtailed his thinking, publishing or presenting his ideas at conferences.3 Although the Lucasian Professorship does not carry any significant responsibilities, Professor Hawking has continued to teach and supervise students.
In 1974 Hawking was inducted into the Royal Society. The Royal Society traditional induction ceremony includes the new members walking on stage and signing a ledger book. This book goes back to the earliest days of the society with even the signature of Sir Isaac Newton. When Hawking was inducted, the tradition was broken when Sir Alan Hodgkin, the president of the Royal Society, carried the book to where Hawking was seated for his signature.4 The entry of Hawking into the Royal Society is an achievement that cannot be overstated, when one considers that he was not expected to live beyond twenty--five years of age.5 Hawking still believes that being inducted into the Royal Society was the proudest moment of his career.6 Hawking has received numerous awards for his work, one of the most important, the Albert Einstein Award, in 1978.7 He won the Adams Prize in 1966 for an essay called "Singularities and the Geometry of Spacetime"'.8 Other awards include two in 1975, the Eddington Medal from the Royal Astronomical Society and the Pius XI Medal from the Pontifical Academy of Science at the Vatican. In 1976, he was awarded the Hopkins Prize, the Dannie Heinemann Prize, the Maxwell Prize and the Hughes Medal from the Royal Society.9 In 1988, he received the Israeli Wolf Foundation Prize in Physics, shared with Roger Penrose.10 In 1987, he received the Paul Dirac Medal from the Institute of Physics, named in honor of the former Lucasian Professor.11 Finally, the British throne has seen fit to make him a Commander of the British Empire (CBE), and in 1989, Queen Elizabeth also made him a Companion of Honour.12 He has eleven honorary doctorate degrees from some of the most prestigious institutions in the world: Oxford (1978), University of Chicago (1981), University of Notre Dame (1982), Princeton University (1982), New York University (1982), University of Leeds (1987), University of Newcastle (1987), Tufts University (1989), Yale University (1989), University of Cambridge (1989) and Harvard University (1990).13
Professor Hawking's father, Frank, was a specialist in tropical medicine and his profession often kept him away from the family. His mother, Isobel, was a very politically active person. Both of them had major influence on his development, although he did not really do what they had hoped. He has two younger sisters, Mary and Philippa and one younger, adopted brother, Edward. His family today is his wife, Jane, and their three children, Robert, born in 1967, daughter Lucy, born 1970 and son Timothy born in 1979. It is clear that Jane's devotion and help were the difference between his success and failure.
Any scientist, especially a theoretical physicist, constantly runs the risk of being wrong. Some errors are not discovered for centuries; others are noticed almost immediately. Less than an error are refinements to theories as science progresses forward. The process is progress as understanding grows and moves into deeper levels. A good example of this process is the gravitational theory of Sir Isaac Newton. In an amazing moment of insight (preceded by a lot of hard work), Newton unified the falling of an apple from a tree with the movement of planets around the sun. He was able to explain with concepts and mathematics how gravity is the same for both ideas. Spacecraft have been sent to the moon and even beyond the solar system with the principles he set down. It all works quite well in our every day lives in a predictable manner. It is known, however, that certain small discrepancies exist. The best example is that the orbit of the planet Mercury differs by 43 seconds of arc from the Newtonian calculation. This is clearly a very small number that would not truly affect us, but good scientists do not like such discrepancies.
In the beginning of this century, Albert Einstein produced his General and Special Theories of Relativity. Neither relativity nor the 43 seconds of arc affects our everyday lives. Relativity affects things that move close to the speed of light. It also, in the midst of a complicated theory, predicted that Mercury's orbit will differ by 43 seconds of arc when it is close to the sun. This represents an important refinement in understanding gravity, but does not make Newton wrong. Such refinements will continue and Hawking expects to contribute to these refinements.
Hawking, however, has also made some well known mistakes which are worth mentioning in the context of development. It is important to understand that as any new theory is developed, researchers go through a peer reviewed trial and error process, so that not every idea presented is proved to be correct. One makes an effort to be right, but no one is right all the time because no one has all the knowledge required. The development of this knowledge is what science is all about.
One example of such a mistake was his belief that if the universe collapsed after a time of expansion, that disorder would decrease as the universe became smaller towards the point of origin. This implied that what we see today as time moving forward would be reversed so that people would begin to live their lives in reverse. This is the material one uses for science fiction. The idea was attractive to Hawking because of its symmetry. He was pointed in the right direction by a colleague and a student.
He philosophizes on mistakes by stating one should simply admit them and move on, citing the examples of Einstein and Eddington. Both of these great men made great errors and tried to hold onto their false conclusions in the face of overwhelming evidence. Einstein eventually admitted to his mistake, the cosmological constant, after a long time of trying to create a model of the universe that was static.14
Hawking entered Cambridge from Oxford as a graduate student with a well-known story of how he got there. Apparently he was very close to not getting a first-level evaluation for his final exams, so he told his examiners that if he received a first, he would go to Cambridge and that if he got a second, he would stay at Oxford. He got the first.15
After he earned his Ph.D. degree at 23 years of age, he remained at Cambridge working his way up to the Lucasian Professorship. The inaugural lecture given on April 29, 1980, for the Lucasian Professorship was noteworthy if for its title alone, Is the End in Sight for Theoretical Physics? 16 It is not the first time someone has predicted that we have or would soon have figured it all out. The rest of the time physics would be just filling in the details. Hawking is suggesting that by the end of the century, just a few years away, he or someone will have unified the main theories into one theory so that gravity would be added to the already unified forces of nature. It would not really be a complete understanding of existence, but would provide the framework.17
Hawking's bestseller, A Brief History of Time, was unusual for a scientist in a field that was somewhat remote from the average person.18 It remained for years on the New York Times bestseller list and has been published in many languages. He has managed to touch a great number of people with his thoughts on such esoteric concepts of time, gravity, relativity and the origin of the universe. It is a remarkable feat. More importantly, it gave him the financial freedom that the Lucasian Chair could not. It is expensive to maintain his standard of living because of his illness and having several children who need schooling did not make life any less expensive. Royalties from the book have helped.
The question of the origin of the universe has fascinated people for centuries. Scientists have been writing the results of their research that tell us what happened in the first few microseconds of the creation of the universe. Professor Hawking is on a quest to find a theory of everything.19 According to Hawking,20 the real problem is that we have an acceptable theory of the large scale universe and we have an acceptable theory of the small scale universe, but these two theories are not compatible. These theories are still considered incomplete, the unification of these theories is the objective of his work. The large scale theory is that of relativity, posed by Albert Einstein, and the small scale theory is that of quantum mechanics, posed by people like Paul Dirac, Max Planck, and Werner Heisenberg. To pull these two theories together requires a quantum theory of gravity.
Physics divides the world into four fundamental forces, the strong force, the weak force, the electromagnetic force and gravity.21 The strong force keeps the nucleus of atoms together by keeping the neutrons and the protons together. It also is the force that keeps the quarks, which make up the neutron and proton from flying apart. The weak force is involved in radioactivity and the decay of atoms. The electromagnetic force is what keeps atoms together through the positive and negative charge of protons and electrons. The negatively charged electrons are kept in place around the positively charged protons in the nucleus. Furthermore, molecules are formed by the sharing of electrons, so this force is also responsible for molecules being held together. This is the basis for chemistry and ultimately biology. Three of these forces work on the small scale, unlike gravity, which is really the weakest of all these forces, but works over great distances. The electroweak theory has joined the electromagnetic force and the weak force by virtue of particles that transmit the force. These particles have been observed experimentally. The strong force is being joined with this theory in several competing theories known as Grand Unification Theories (GUTs) and Super Symmetry (SUSYs). Gravity has so far eluded capture.22 Black holes are a fairly recent idea that seems more like science fiction material than real physics. A black hole is the result of matter so compact and dense that the gravitational effects are increased so that nothing can escape, not even light, hence the name black hole.
To escape from the earth a momentum of about seven miles per second or about 25,000 miles per hour is required. This is determined by the mass of the earth, not by its size. A black hole can be different sizes, but it must of course have enough mass to keep light from escaping. A black hole has been theoretically proposed as a consequence of known and expected conditions. In the real world a black hole could be "seen" by its effects. For example, if a star were losing matter to a nearby black hole, the trail of material from the star to an unseen black hole would be visible.
A black hole owes its existence to Einstein's theory of gravity. When a massive star runs out of fuel, it stops burning allowing the leftover matter to fall to the center in a free fall collapse. According to Einstein, time and space as we know them become intertwined in such a way that this free fall continues forever: time just slows down indefinitely. This phenomenon happens only to massive stars because it requires a lot of matter above a certain threshold.
Hawking has made some advances in the theory of black holes which have helped to advance his reputation as a theorist.23 He has brought the theoretical free fall into view as a physical entity by including thermodynamics into the equation. his theory a black hole emits thermal radiation at a definite . Freeman Dyson calls the results of an equation Hawking's constant, S = kA, where S is the entropy, or heat capacity, of the black holes and is the surface area. Hawking's constant is the k. What this tells us that the area of a black hole is related to the entropy/heat capacity of the hole. The heat loss or thermal radiation is in fact measurable. The black is not permanent, but in fact will dissipate at some measurable rate. A summary of the process is based in quantum mechanics. Pairs of particles are constantly coming into and out of existence in the vacuum of space. Each pair is composed of a particle and its antiparticle. Their lifetime is very brief, and they destroy each other. If this event occurs near a black hole the antimatter particle may fall into the black hole and the positive particle is then free to travel away from the black hole, appearing as though it came from inside the black hole. The negative particle falling into the black hole will decrease the mass and energy of the black hole. This heat loss is known as Hawking Radiation.24 This could lead at some point to a black hole exploding if it has the correct characteristics.25
Cosmology is the study of the universe as a whole. The origin of the universe is a key part of this study, as is the fate of the universe. For many centuries, the universe was considered as unchanging, with the only noticeable difference in a few circles, was it had a beginning. In Western religions there was a point of creation, but when it was created, it was created about as we see it. In Eastern religions, there was a continuous creating, a growing and shrinking cycle that was repeated forever.
hole Western science mostly agrees that the Big Bang explanation is the correct one. At some point about 15 or so billion years ago the universe was infinitely small, infinitely dense and infinitely hot. It exploded, expanded, inflated and cooled, producing the universe we now see and are trying to understand. There is a detailed explanation of the process that works its way backwards from today to the beginning. The evidence for the theory was proposed and the search for the evidence began. Some of the evidence has been found, for example, the so-called 3 degree background radiation, which would have been the remains of the explosion. It was found, verifying that there was a big bang. Then the inflationary model of Alan Guth was proposed to explain some problems. In 1992, the COBE satellite found the evidence that the inflationary model was correct, or at least consistent with the evidence.
On the small scale universe, experimental physicists have been ramping up the energies of their accelerators to find out if the models of how matter is constructed is correct. So far they have shown that what is called the Standard Model is correct. And so far, the construction of matter, and its deconstruction, is consistent with the model of the Big Bang. There has even been a book called The First Three Minutes26 which describes events in very small chunks of time, hundredths of a second. However, as we get down to time zero, we are not so sure what happened. This is where Hawking is working. He proposes a singularity at the beginning, and probably at the end, of the universe. A singularity is a point where time and space have infinite curvature and there is an infinite density of matter.
A great contribution of Hawking and his colleagues was the proof that time and space have a real beginning.27 In line with that thought, is that time and space also have an end. According to Hawking, as one collapses the known universe further and further back to the point of the Big Bang, time as we know it cannot be defined. In this sense, time begins. He points out that it is not true that the universe started out as a lump of matter hanging in space. There was no space as we know it in which to hang it. Space and time were created as part of the Big Bang.
The Arrow of Time, according to Hawking, points in only one direction. We all know intuitively that time moves forward, we only remember the past and we know that time travel, although attractive, is unlikely. This is really a kind of mystery for the theorist, because other measures of symmetry do not suffer from this inadequacy. This problem is very complicated, so some background is in order. Although there are numerous kinds of symmetry in the world of subatomic particles in this context there are three important symmetries: P, C and T, giving the PCT theorem. P is parity, C is charge, and T is time. Each is binary operation, that is to say a plus or a minus in an equation. One example would be charge, it can be negative or positive. In an atom the center, the nucleus, is made of positive protons (and usually neutral neutrons) and negatively charged electrons surround the nucleus, giving us an overall neutral atom. The pluses and minuses are equal so they cancel out. This symmetry and the breaking of this symmetry is very important to us in our everyday lives, even though we generally do not pay it any mind. The key point here is that the charge can positive or negative without any difficulty. Parity is the same, it can be odd or even.28 The problem is that time in an equation can be forward or backward, but our real life experience is not the same, it is only forward.29 These symmetries have much success in explaining and predicting events and even new particles. It is a bit of a problem that time is not in step with the others.
Hawking offers his explanation starting with the identification of three arrows of time, the thermodynamic, the psychological, and the cosmological.30 The thermodynamic arrow of time is related to the idea of entropy. Entropy is the measure of disorder in a system. If the system has low entropy, then it is highly ordered. The second law of thermodynamics says that entropy in any system is always increasing, that is to say, that all systems tend to become disordered. Furthermore, you can not reverse the disorder once it has happened.31 Entropy is a measure of heat loss in one sense, if you think of heat as a disordered form of energy. Entropy is increased by spontaneous activity in an isolated system. If somehow an outside agent interacts, the entropy could be reversed in the isolated system, but it would increase in the system of the interfering agent. The consequence of this is the overall entropy in the universe is increasing. Ultimately the universe will be in a state of equilibrium at the highest level of entropy.
The psychological arrow is the one that we as humans are aware of in the separation of past and future by the now. We only know about the past and are learning about the future as we move forward. This arrow is the most obvious and points the same way as the thermodynamic one. We need this to be the case so that we can exist: we are energy consumers.
The last arrow is the cosmological one, the universe is expanding, not contracting. This is a well known concept that has been clearly measured on an astronomical scale with galaxy movement. The universe is expanding in the same direction as the increase in disorder. Hawking comes to the conclusion that intelligent life could not exist in a contracting universe because of what is called the no boundary condition. One way to look at it is the shape of the earth, it has no real boundary and you can go around and around it without running into a wall, a cliff or something else that defines the end of it. However, it is a finite entity. Hawking proposes that the universe is the same, it has no boundary, but it is finite and expanding. The universe with a no boundary condition would have "started off with just the minimum possible nonuniformity allowed by the uncertainty principle."32 The end result would be the complicated structures we see, such as galaxies and us. Other consequences are more interesting, such as other universes.
Baby universes are the consequence of a modification of the Big Bang theory where the universe is viewed more as a bubble in champagne. The bubble that is our universe conforms to the inflationary model of Alan Guth at MIT. It also allows for the possibility of an infinite number of these bubble universes and the possibility that any of these could produce another bubble which would be another universe, therefore baby universes.33
If there are such things as other universes, the question immediately arises, is there is any way to communicate with them? Hawking's work suggests the possibility of wormholes that connect these other universes, but he does not see humans traveling between them. It would work at the level of energy and subatomic particles.
Hawking has not had very much to say from his point of view about religion, but there is quite a bit from the point of view of others because of the implications of his theories.34 He has tended to make statements that cause discussion rather then engage in the discussion. In his book A Brief History of Time, Hawking proposes a universe that has a closed surface formed by space and time with the no boundary condition, there may be neither a beginning nor an end. If this is the case the need for a creator vanishes. The place for God seems to be, at the moment, a creator who started the universe according to some set of laws and then sat back and watched it move forward. However, even that role seems to be in jeopardy.35 In an interesting commentary, Hawking points out that St.Augustine was one of the first to say that time was a property of the universe, that time did not exist until God created the universe.36 Hawking agrees that time is a property of the universe, but that is as far as he goes.
Hawking generally does not acknowledge the existence of God, but he has certainly generated discussion on his views. He has stated that he believes the question is still open, but Craig hears him closing it off, and with an incorrect conclusion.37 Craig's article is long and involved in arguments that have their basis in the belief structure of St.Thomas and St.Augustine where it is a given that God exists and all arguments for his existence flow from this starting point. He unfortunately uses metaphysics as a standard of measurement in an inappropriate manner. Where Hawking puts forth the proposition that there may be no place for a creator if the universe has no beginning, Craig counters with the argument that Hawking does not distinguish between two types of creation, the original and the continuous. The problem here is that Hawking is only investigating the origin, the possibility of an ongoing creation is irrelevant. Craig has brought this into the conversation to argue for the existence of God when Hawking only opened the door to question the need for a creator.
Craig also shows some signs of understanding the mathematics by correctly pointing out that Hawking needs to demonstrate that a mathematical statement has a counterpart in physical reality. He then shows a lack of understanding when he complains that the use of imaginary time as a mathematical device is somehow intellectually dishonest. In the end, Craig paraphrases Hawking's question with: "What price, then, for no Creator?" If the best Craig can do is complain about the price of truth, then he has diminished the real subject under discussion.
Hawking is only the most recent in a long tradition of scientists who have wrestled with the question of God and have stimulated discussion with others by their theories and findings. The history goes back to Galileo and his battle with the Catholic Church and will probably continue for a long while. Hawking spent time at the Vatican at conferences38 at their invitation, and has works published by them. He even received an award from Vatican. He may have a difference of opinion when it comes to God, but he has a better working relationship with the church than Galileo did.
- 1 Parts of this section are the result of electronic mail communications with Prof. Hawking and a brief interview at MIT on August 2, 1994.
- 2 John Boslough, Stephen Hawking's Universe (New York: Morrow, 1985), 127.
- 3 Stephen Hawking, A Brief History of Time: From the Big Bang to Black Holes (New York: Bantam, 1988), vii.
- 4 Ferguson 1991 91.
- 5 Boslough, 26.
- 6 Michael White, Stephen Hawking: A Life in Science (New York: Dutton, 1992), 134.
- 7 White, 187.
- 8 White, 101.
- 9 White, 163.
- 10 White, 271.
- 11 Stephen Hawking, A Short History (Cambridge: Privately printed, 1994), 9.
- 12 White, 271.
- 13 Hawking, A Short History, 8.
- 14 Hawking, A Brief History of Time, 150.
- 15 White, 54.
- 16 Boslough, Appendix.
- 17 Hawking, A Brief History of Time, 169.
- [8 White, 4.
19 Ferguson 1991 13.
- 20 Hawking, A Brief History of Time, 11.
- 21 Timothy Ferris, ed., The World Treasury of Physics, Astronomy, and Mathematics (Boston: Little, Brown and Company, 1991), 118.
- 22 Hawking, A Brief History of Time, 69.
- 23 Ferris, 132.
- 24 White, 150.
- 25 Jayant Narlikar, Introduction to Cosmology (Boston: Jones and Bartlett, 1983), 225.
- 26 Steven Weinberg, The First Three Minutes (New York: Bantam, 1977).
- 27 Boslough, 56.
- 28 Mauldin, 219.
- 29 Hawking, A Brief History of Time, 144.
- 30 Hawking, A Brief History of Time, 145.
- 31 Jim Baggott, The Meaning of Quantum Theory (Oxford: Oxford University Press, 1992), 174.
- 32 Hawking A Brief History of Time, 140.
- 33 White, 207.
- 34 White 1992 4.
- 35 Hawking 1988 140.
- 36 Hawking A Brief History of Time, 8.
- 37 Craig 1990.
- 38 Hawking 1988 116.