Great Throughts Treasury

"When I gave a lecture in Japan, I was asked not to mention the possible re-collapse of the universe, because it might affect the stock market. However, I can re-assure anyone who is nervous about their investments that it is a bit early to sell: even if the universe does come to an end, it won't be for at least twenty billion years. By that time, maybe the GATT trade agreement will have come into effect."

"When asked, 'What did God do before he created the universe?' St. Augustine didn´t reply, 'he was preparing Hell for people who asked such questions.' Instead, he said that time was a property of the universe that God created, and that time did not exist before the beginning of the universe."

"When people ask me if a god created the universe, I tell them that the question itself makes no sense. Time didn’t exist before the big bang, so there is no time for god to make the universe in. It’s like asking directions to the edge of the earth; The Earth is a sphere; it doesn’t have an edge; so looking for it is a futile exercise. We are each free to believe what we want, and it’s my view that the simplest explanation is; there is no god. No one created our universe,and no one directs our fate. This leads me to a profound realization; There is probably no heaven, and no afterlife either. We have this one life to appreciate the grand design of the universe, and for that I am extremely grateful."

"When one's expectations are reduced to zero, one really appreciates everything one does have."

"When we look at the universe, we see it as it was in the past."

"When the star had exhausted its nuclear fuel, there would be nothing to maintain the outward pressure, and the star would begin to collapse because of its own gravity. As the star shrank, the gravitational field at the surface would become stronger and the escape velocity would increase. By the time the radius had got down to 10 kilometers the escape velocity would have increased to 100,000 kilometers per second, the velocity of light. After that time any light emitted from the star would not be able to escape to infinity but would be dragged back by the gravitational field. According to the special theory of relativity nothing can travel faster than light, so that if light cannot escape, nothing else can either. The result would be a black hole: a region of space-time from which it is not possible to escape to infinity."

"With the success of scientific theories in describing events, most people have come to believe that God allows the universe to evolve according to a set of laws and does not intervene in the universe to break these laws. However, the laws do not tell us what the universe should have looked like when it started -- it would still be up to God to wind up the clockwork and choose how to start it off. So long as the universe had a beginning, we could suppose it had a creator. But if the universe is really completely self-contained, having no boundary or edge, it would have neither beginning nor end: it would simply be. What place, then, for a creator?"

"Women. They are a complete mystery. [When asked what he thinks about most during the day]"

"Where do we come from? How did the universe begin? Why is the universe the way it is? How will it end? All my life, I have been fascinated by the big questions that face us, and have tried to find scientific answers to them. If, like me, you have looked at the stars, and tried to make sense of what you see, you too have started to wonder what makes the universe exist. The questions are clear, and deceptively simple. But the answers have always seemed well beyond our reach. Until now. The ideas which had grown over two thousand years of observation have had to be radically revised. In less than a hundred years, we have found a new way to think of ourselves. From sitting at the center of the universe, we now find ourselves orbiting an average-sized sun, which is just one of millions of stars in our own Milky Way galaxy. And our galaxy itself is just one of billions of galaxies, in a universe that is infinite and expanding. But this is far from the end of a long history of inquiry. Huge questions remain to be answered, before we can hope to have a complete picture of the universe we live in. I want you to share my excitement at the discoveries, past and present, which have revolutionized the way we think. From the Big Bang to black holes, from dark matter to a possible Big Crunch, our image of the universe today is full of strange sounding ideas, and remarkable truths. The story of how we arrived at this picture is the story of learning to understand what we see."

"You cannot understand the glories of the universe without believing there is some Supreme Power behind it."

"Yet if there really were a complete unified theory, it would also presumably determine our actions—so the theory itself would determine the outcome of our search for it! And why should it determine that we come to the right conclusions from the evidence? Might it not equally well determine that we draw the wrong conclusion? Or no conclusion at all?"

"Nuclear weapons need large facilities, but genetic engineering can be done in a small lab. You can't regulate every lab in the world. The danger is that either by accident or design, we create a virus that destroys us."

"Among the heresies was the idea that nature follows laws, because this conflicts with God?s omnipotence. Interestingly, Pope John was killed by the effects of the law of gravity a few months later when the roof of his palace fell in on him."

"Anaximander, a friend and possibly a student of Thales, argued that since human infants are helpless at birth, if the first human had somehow appeared on earth as an infant, it would not have survived. In what may have been humanity's first inkling of evolution, people, Anaximander reasoned, must therefore have evolved from other animals whose young are hardier."

"A few years ago the city council of Monza, Italy, barred pet owners from keeping goldfish in curved goldfish bowls. The measure?s sponsor explained the measure in part by saying that it is cruel to keep a fish in a bowl with curved sides because, gazing out, the fish would have a distorted view of reality."

"Because gravity shapes space and time, it allows space time to be locally stable but globally unstable. On the scale of the entire universe, the positive energy of the matter can be balanced by the negative gravitational energy, and so there is no restriction on the creation of whole universes. Because there is a law like gravity, the universe can and will create itself from nothing."

"As a result, in more than three dimensions the sun would not be able to exist in a stable state with its internal pressure balancing the pull of gravity. It would either fall apart or collapse to form a black hole, either of which could ruin your day."

"Consider the apparent dimension of the universe. According to M-theory, space-time has ten space dimensions and one time dimension. The idea is that seven of the space dimensions are curled up so small that we don?t notice them, leaving us with the illusion that all that exist are the three remaining large dimensions we are familiar with."

"But humans are a curious species. We wonder, we seek answers. Living in this vast world that is by turns kind and cruel, and gazing at the immense heavens above, people have always asked a multitude of questions: How can we understand the world in which we find ourselves? How does the universe behave? What is the nature of reality? Where did all this come from? Did the universe need a creator?"

"Both observer and observed are parts of the world that has an objective existence, and any distinction between them has no meaningful significance. In other words, if you see a herd of zebras fighting for a spot in the parking garage, it is because there really is a herd of zebras fighting for a spot in the parking garage."

"Bodies such as stars or black holes cannot just appear out of nothing. But a whole universe can."

"calculations show that a change of as little as 0.5 percent in the strength of the strong nuclear force, or 4 percent in the electric force, would destroy either nearly all carbon or all oxygen in every star, and hence the possibility of life as we know it. Change those rules of our universe just a bit, and the conditions for our existence disappear!"

"Descartes, for instance, in order to preserve the idea of free will, asserted that the human mind was something different from the physical world and did not follow its laws. In his view a person consists of two ingredients, a body and a soul. Bodies are nothing but ordinary machines, but the soul is not subject to scientific law."

"Do we really have reason to believe that an objective reality exists?"

"Feynman once wrote, I think I can safely say that nobody understands quantum mechanics."

"How do I know that a table still exists if I go out of the room and can?t see it? What does it mean to say that things we can?t see, such as electrons or quarks?the particles that are said to make up the proton and neutron?exist? One could have a model in which the table disappears when I leave the room and reappears in the same position when I come back, but that would be awkward, and what if something happened when I was out, like the ceiling falling in? How, under the table-disappears-when-I-leave-the-room model, could I account for the fact that the next time I enter, the table reappears broken, under the debris of the ceiling? The model in which the table stays put is much simpler and agrees with observation. That is all one can ask."

"If nature is governed by laws, three questions arise: What is the origin of the laws? Are there any exceptions to the laws, i.e., miracles? Is there only one set of possible laws?"

"If the theory is confirmed by observation, it will be the successful conclusion of a search going back more than 3,000 years. We will have found the grand design."

"If the Earth stopped spinning, then according to Newton's law of any object not tied to the Earth will continue to move at the speed of rotation of the Earth (1100 miles per hour, or 1770 km per hour at the equator)"

"In fact, according to quantum physics, each particle has some probability of being found anywhere in the universe."

"Ignorance of nature?s ways led people in ancient times to invent gods to lord it over every aspect of human life."

"In fact, if general relativity were not taken into account in GPS satellite navigation systems, errors in global positions would accumulate at a rate of about ten kilometers each day!"

"In 1992 came the first confirmed observation of a planet orbiting a star other than our sun."

"In modern science laws of nature are usually phrased in mathematics. They can be either exact or approximate, but they must have been observed to hold without exception?if not universally, then at least under a stipulated set of conditions. For"

"In the early universe?when the universe was small enough to be governed by both general relativity and quantum theory?there were effectively four dimensions of space and none of time. That means that when we speak of the beginning of the universe, we are skirting the subtle issue that as we look backward toward the very early universe, time as we know it does not exist! We must accept that our usual ideas of space and time do not apply to the very early universe. That is beyond our experience, but not beyond our imagination, or our mathematics."

"In physics a system is said to have a symmetry if its properties are unaffected by a certain transformation such as rotating it in space or taking its mirror image. For example, if you flip a donut over, it looks exactly the same (unless it has a chocolate topping, in which case it is better just to eat it)."

"In the Game of Life, as in our world, self-reproducing patterns are complex objects. One estimate, based on the earlier work of mathematician John von Neumann, places the minimum size of a self-replicating pattern in the Game of Life at ten trillion squares?roughly the number of molecules in a single human cell."

"La capacidad humana para sentirse culpable es tal que siempre podemos hallar maneras de acusarnos a nosotros mismos."

"It is hard to imagine how free will can operate if our behavior is determined by physical law, so it seems that we are no more than biological machines and that free will is just an illusion."

"Many people throughout the centuries has attributed to God the beauty and complexity of nature that, in his time, seemed to have no scientific explanation. But as Darwin and Wallace explained how the apparently miraculous design of living forms could appear without the intervention of a Supreme Being, the concept of the multiverse may explain the fine tuning of the physical laws without a benevolent Creator who made the universe our advantage."

"Our universe and its laws appear to have a design that both is tailor-made to support us and, if we are to exist, leaves little room for alteration. That is not easily explained, and raises the natural question of why it is that way."

"Nature and Nature?s laws lay hid in night: God said, Let Newton be! and all was light."

"Our very existence imposes rules determining from where and at what time it is possible for us to observe the universe. That is, the fact of our being restricts the characteristics of the kind of environment in which we find ourselves. That principle is called the weak anthropic principle."

"Quantum physics is a new model of reality that gives us a picture of the universe that in many fundamental concepts for our intuitive understanding of reality meaningless."

"Quantum physics might seem to undermine the idea that nature is governed by laws, but that is not the case. Instead it leads us to accept a new form of determinism: given the state of a system at some time, the laws of nature determine the probabilities of various futures and pasts rather than determining the future and past with certainty."

"Quantum physics tells us that no matter how thorough our observation of the present, the (unobserved) past, like the future, is indefinite and exists only as a spectrum of possibilities. The universe, according to quantum physics, has no single past, or history. The fact that the past takes no definite form means that observations you make on a system in the present affect its past. That is underlined rather dramatically by a type of experiment thought up by physicist John Wheeler, called a delayed-choice experiment. Schematically, a delayed-choice experiment is like the double-slit experiment we just described, in which you have the option of observing the path that the particle takes, except in the delayed-choice experiment you postpone your decision about whether or not to observe the path until just before the particle hits the detection screen. Delayed-choice experiments result in data identical to those we get when we choose to observe (or not observe) the which-path information by watching the slits themselves. But in this case the path each particle takes?that is, its past?is determined long after it passed through the slits and presumably had to decide whether to travel through just one slit, which does not produce interference, or both slits, which does. Wheeler even considered a cosmic version of the experiment, in which the particles involved are photons emitted by powerful quasars billions of light-years away. Such light could be split into two paths and refocused toward earth by the gravitational lensing of an intervening galaxy. Though the experiment is beyond the reach of current technology, if we could collect enough photons from this light, they ought to form an interference pattern. Yet if we place a device to measure which-path information shortly before detection, that pattern should disappear. The choice whether to take one or both paths in this case would have been made billions of years ago, before the earth or perhaps even our sun was formed, and yet with our observation in the laboratory we will be affecting that choice. In"

"So look carefully at the map of the microwave sky. It is the blueprint for all the structure in the universe. We are the product of quantum fluctuations in the very early universe. If one were religious, one could say that God really does play dice."

"Recent experiments in neuroscience support the view that it is our physical brain, following the known laws of science, that determines our actions, and not some agency that exists outside those laws. For example, a study of patients undergoing awake brain surgery found that by electrically stimulating the appropriate regions of the brain, one could create in the patient the desire to move the hand, arm or foot, or to move the lips and talk. It is hard to imagine how free will can operate if our behaviour is determined by physical law, so it seems that we are no more than biological machines and that free will is just an illusion."

"Single photons are not usually evident, but in the laboratory we can produce a beam of light so faint that it consists of a stream of single photons, which we can detect as individuals just as we can detect individual electrons or buckyballs. And we can repeat Young?s experiment employing a beam sufficiently sparse that the photons reach the barrier one at a time, with a few seconds between each arrival. If we do that, and then add up all the individual impacts recorded by the screen on the far side of the barrier, we find that together they build up the same interference pattern that would be built up if we performed the Davisson-Germer experiment but fired the electrons (or buckyballs) at the screen one at a time. To physicists, that was a startling revelation: If individual particles interfere with themselves, then the wave nature of light is the property not just of a beam or of a large collection of photons but of the individual particles."

"Some people make a great mystery of this idea, sometimes called the multiverse concept, but these are just different expressions of the Feynman sum over histories."