Click here to Download Brief Answers to the Big Questions PDF Book by Stephen Hawking English having PDF Size 4.2 MB and No of Pages 157.
People have always wanted answers to the big questions. Where did we come from? How did the universe begin? What is the meaning and design behind it all? Is there anyone out there? The creation accounts of the past now seem less relevant and credible. They have been replaced by a variety of what can only be called superstitions, ranging from New Age to Star Trek.
Brief Answers to the Big Questions PDF Book by Stephen Hawking
| Name of Book | Brief Answers to the Big Questions |
| Author | Stephen Hawking |
| PDF Size | 4.2 MB |
| No of Pages | 157 |
| Language | English |
| Buy Book From Amazon | |
About Book – Brief Answers to the Big Questions PDF Book
But real science can be far stranger than science fiction, and much more satisfying. I am a scientist. And a scientist with a deep fascination with physics, cosmology, the universe and the future of humanity. I was brought up by my parents to have an unwavering curiosity and, like my father, to research and try to answer the many questions that science asks us.
I have spent my life travelling across the universe, inside my mind. Through theoretical physics, I have sought to answer some of the great questions. At one point, I thought I would see the end of physics as we know it, but now I think the wonder of discovery will continue long after I am gone. We are close to some of these answers, but we are not there yet.
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The problem is, most people believe that real science is too difficult and complicated for them to understand. But I don’t think this is the case. To do research on the fundamental laws that govern the universe would require a commitment of time that most people don’t have; the world would soon grind to a halt if we all tried to do theoretical physics.
But most people can understand and appreciate the basic ideas if they are presented in a clear way without equations, which I believe is possible and which is something I have enjoyed trying to do throughout my life. It has been a glorious time to be alive and doing research in theoretical physics. Our picture of the universe has changed a great deal in the last fifty years, and I’m happy if I have made a contribution.
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One of the great revelations of the space age has been the perspective it has given humanity on ourselves. When we see the Earth from space, we see ourselves as a whole. We see the unity, and not the divisions. It is such a simple image with a compelling message; one planet, one human race. I want to add my voice to those who demand immediate action on the key challenges for our global community.
I hope that going forward, even when I am no longer here, people with power can show creativity, courage and leadership. Let them rise to the challenge of the sustainable development goals, and act, not out of self-interest, but out of common interest. I am very aware of the preciousness of time. Seize the moment. Act now.
If you accept, as I do, that the laws of nature are fixed, then it doesn’t take long to ask: what role is there for God? This is a big part of the contradiction between science and religion, and although my views have made headlines, it is actually an ancient conflict. One could define God as the embodiment of the laws of nature. However, this is not what most people would think of as God. Brief Answers to the Big Questions PDF Book
They mean a human-like being, with whom one can have a personal relationship. When you look at the vast size of the universe, and how insignificant and accidental human life is in it, that seems most implausible. I use the word “God” in an impersonal sense, like Einstein did, for the laws of nature, so knowing the mind of God is knowing the laws of nature.
My prediction is that we will know the mind of God by the end of this century. The one remaining area that religion can now lay claim to is the origin of the universe, but even here science is making progress and should soon provide a definitive answer to how the universe began. I published a book that asked if God created the universe, and that caused something of a stir.
People got upset that a scientist should have anything to say on the matter of religion. I have no desire to tell anyone what to believe, but for me asking if God exists is a valid question for science. After all, it is hard to think of a more important, or fundamental, mystery than what, or who, created and controls the universe. I think the universe was spontaneously created out of nothing, according to the laws of science. Brief Answers to the Big Questions PDF Book
The basic assumption of science is scientific determinism. The laws of science determine the evolution of the universe, given its state at one time. These laws may, or may not, have been decreed by God, but he cannot intervene to break the laws, or they would not be laws. That leaves God with the freedom to choose the initial state of the universe, but even here it seems there may be laws.
So God would have no freedom at all. Despite the complexity and variety of the universe, it turns out that to make one you need just three ingredients. Let’s imagine that we could list them in some kind of cosmic cookbook. So what are the three ingredients we need to cook up a universe? The first is matter— stuff that has mass. Matter is all around us, in the ground beneath our feet and out in space.
Dust, rock, ice, liquids. Vast clouds of gas, massive spirals of stars, each containing billions of suns, stretching away for incredible distances. The second thing you need is energy. Even if you’ve never thought about it, we all know what energy is. Something we encounter every day. Look up at the Sun and you can feel it on your face: energy produced by a star ninety-three million miles away. Brief Answers to the Big Questions PDF Book
Energy permeates the universe, driving the processes that keep it a dynamic, endlessly changing place. So we have matter and we have energy. The third thing we need to build a universe is space. Lots of space. You can call the universe many things—awesome, beautiful, violent—but one thing you can’t call it is cramped.
Wherever we look we see space, more space and even more space. Stretching in all directions. It’s enough to make your head spin. So where could all this matter, energy and space come from? We had no idea until the twentieth century. I would like to speculate a little on the development of life in the universe, and in particular on the development of intelligent life.
I shall take this to include the human race, even though much of its behaviour throughout history has been pretty stupid and not calculated to aid the survival of the species. Two questions I shall discuss are “What is the probability of life existing elsewhere in the universe?” and “How may life develop in the future?” It is a matter of common experience that things get more disordered and chaotic with time. Brief Answers to the Big Questions PDF Book Download
This observation even has its own law, the so-called second law of thermodynamics. This law says that the total amount of disorder, or entropy, in the universe always increases with time. However, the law refers only to the total amount of disorder. The order in one body can increase provided that the amount of disorder in its surroundings increases by a greater amount.
This is what happens in a living being. We can define life as an ordered system that can keep itself going against the tendency to disorder and can reproduce itself. That is, it can make similar, but independent, ordered systems. To do these things, the system must convert energy in some ordered form—like food, sunlight or electric power—into disordered energy, in the form of heat.
In this way, the system can satisfy the requirement that the total amount of disorder increases while, at the same time, increasing the order in itself and its offspring. This sounds like parents living in a house which gets messier and messier each time they have a new baby. A living being like you or me usually has two elements: a set of instructions that tell the system how to keep going and how to reproduce itself. Brief Answers to the Big Questions PDF Book Download
And a mechanism to carry out the instructions. In biology, these two parts are called genes and metabolism. But it is worth emphasising that there need be nothing bio-logical about them. For example, a computer virus is a program that will make copies of itself in the memory of a computer, and will transfer itself to other computers.
Thus it fits the definition of a living system that I have given. Like a biological virus, it is a rather degenerate form, because it contains only instructions or genes, and doesn’t have any metabolism of its own. Instead, it reprograms the metabolism of the host computer, or cell. Some people have questioned whether viruses should count as life.
Because they are parasites, and cannot exist independently of their hosts. But then most forms of life, ourselves included, are parasites, in that they feed off and depend for their survival on other forms of life. I think computer viruses should count as life. Maybe it says something about human nature that the only form of life we have created so far is purely destructive. Brief Answers to the Big Questions PDF Book Download
Talk about creating life in our own image. I shall return to electronic forms of life later on. However, Planck showed one could avoid this disaster if one gave up the idea that the amount of radiation could have just any value, and said instead that radiation came only in packets or quanta of a certain size. It is a bit like saying that you can’t buy sugar loose in the supermarket, it has to be in kilogram bags.
The energy in the packets or quanta is higher for ultra-violet and X-rays than for infra-red or visible light. It means that unless a body is very hot, like the Sun, it will not have enough energy to give off even a single quantum of ultra-violet or X-rays. That is why we don’t get sunburn from a cup of coffee.
Planck regarded the idea of quanta as just a mathematical trick, and not as having any physical reality, whatever that might mean. However, physicists began to find other behaviour that could be explained only in terms of quantities having discrete or quantised values rather than continuously variable ones. For example, it was found that elementary particles behaved rather like little tops, spinning about an axis. Brief Answers to the Big Questions PDF Book Free
But the amount of spin couldn’t have just any value. It had to be some multiple of a basic unit. Because this unit is very small, one does not notice that a normal top really slows down in a rapid sequence of discrete steps, rather than as a continuous process. But, for tops as small as atoms, the discrete nature of spin is very important.
It was some time before people realised the implications of this quantum behaviour for determinism. It was not until 1927 that Werner Heisenberg, another German physicist, pointed out that you couldn’t measure simultaneously both the position and speed of a particle exactly. To see where a particle is, one has to shine light on it.
But by Planck’s work one can’t use an arbitrarily small amount of light. One has to use at least one quantum. This will disturb the particle and change its speed in a way that can’t be predicted. To measure the position of the particle accurately, you will have to use light of short wavelength, like ultra-violet, X-rays or gamma rays. Brief Answers to the Big Questions PDF Book Free
But again, by Planck’s work, quanta of these forms of light have higher energies than those of visible light. So they will disturb the speed of the particle more. This created a paradox about the nature of black holes, the incredibly dense objects created by the collapse of stars. One theory suggested that black holes with identical qualities could be formed from an infinite number of different types of stars.
Another suggested that the number could be finite. This is a problem of information—the idea that every particle and every force in the universe contains information. Because black holes have no hair, as the scientist John Wheeler put it, one can’t tell from the outside what is inside a black hole, apart from its mass, electric charge and rotation.
This means that a black hole must contain a lot of information that is hidden from the outside world. But there is a limit to the amount of information one can pack into a region of space. Information requires energy, and energy has mass by Einstein’s famous equation, E = mc2 . So, if there’s too much information in a region of space, it will collapse into a black hole. Brief Answers to the Big Questions PDF Book Free
And the size of the black hole will reflect the amount of information. It is like piling more and more books into a library. Eventually, the shelves will give way and the library will collapse into a black hole. If the amount of hidden information inside a black hole depends on the size of the hole.
One would expect from general principles that the black hole would have a temperature and would glow like a piece of hot metal. But that was impossible because, as everyone knew, nothing could get out of a black hole. Or so it was thought.