However bad life may seem, there is always something you can do and succeed at. Where there's life, there's hope.
Scientists have become the bearers of the torch of discovery in our quest for knowledge.
My goal is simple. It is a complete understanding of the universe, why it is as it is and why it exists at all.
I don't want to write an autobiography because I would become public property with no privacy left.
Life would be tragic if it weren't funny.
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.
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.
If aliens ever visit us, I think the outcome would be much as Christopher Columbus first landed in America, which didn't turn out very well for the Native Americans.
Considering the number of planets and stars that we know exist, it's extremely unlikely that we are the only form of evolved life.
By 2600, the world population would be standing shoulder to shoulder and the electricity consumed would make the earth glow red-hot.
I have found far greater enthusiasm for science in America than here in Britain. There is more enthusiasm for everything in America.
Although quantum mechanics has been around for nearly 70 years, it is still not generally understood or appreciated, even by those that use it to do calculations.
A theory is a good theory if it satisfies two requirements: it must accurately describe a large class of observations on the basis of a model that contains only a few arbitrary elements, and it must make definite predictions about the results of future observations.
So some might imagine that I am an expert on time, although of course these days an expert is not necessarily a good thing to be.
The increase of disorder or entropy with time is one example of what is called an arrow of time, something that distinguishes the past from the future, giving a direction to time.
Only a very few would allow creatures like us to exist. Thus our presence selects out from this vast array only those universes that are compatible with our existence. Although we are puny and insignificant on the scale of the cosmos, this makes us in a sense the lords of creation.
We think that life develops spontaneously on Earth, so it must be possible for life to develop on suitable planets elsewhere in the universe. But we don't know the probability that a planet develops life.
It is reasonable to ask who or what created the universe, but if the answer is God, then the question has merely been deflected to that of who created God.
A society in which the individual feels responsible for his or her actions is more likely to work together and survive to spread its values.
I first had the idea of writing a popular book about the universe in 1982. My intention was partly to earn money to pay my daughter's school fees.
One could imagine such technology outsmarting financial markets, out-inventing human researchers, out-manipulating human leaders, and developing weapons we cannot even understand.
If the government is covering up knowledge of aliens, they are doing a better job of it than they do at anything else.
The question is: is the way the universe began chosen by God for reasons we can't understand, or was it determined by a law of science? I believe the second. If you like, you can call the laws of science 'God', but it wouldn't be a personal God that you could meet, and ask questions.
You may see a cup of tea fall off a table and break into pieces on the floor... But you will never see the cup gather itself back together and jump back on the table. The increase of disorder, or entropy, is what distinguishes the past from the future, giving a direction to time.
We are only the temporary custodians of the particles which we are made of. They will go on to lead a future existence in the enormous universe that made them.
I don't believe that the ultimate theory will come by steady work along existing lines. We need something new. We can't predict what that will be or when we will find it because if we knew that, we would have found it already!
The human race shouldn't have all its eggs in one basket, or on one planet. Let's hope we can avoid dropping the basket until we have spread the load.
There are plenty of dead scientists I admire, but I can't think of any living ones. This is probably because it is only in retrospect that one can see who made the important contributions.
I believe that the long-term future of the human race must be space and that it represents an important life insurance for our future survival, as it could prevent the disappearance of humanity by colonizing other planets.
Doing a job RIGHT the first time gets the job done. Doing the job WRONG fourteen times gives you job security.
Though we feel we can choose what we do, our understanding of the molecular basis of biology shows that biological processes are governed by the laws of physics and chemistry and therefore are as determined as the orbits of the planets.
Though we feel that we can choose what we do, our understanding of the molecular basis of biology shows that biological processes are governed by the laws of physics and chemistry and therefore are as determined as the orbits of the planets. 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 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.
We shouldn't be surprised that conditions in the universe are suitable for life, but this is not evidence that the universe was designed to allow for life. We could call order by the name of God, but it would be an impersonal God. There's not much personal about the laws of physics.
We could call order by the name of God, but it would be an impersonal God. There's not much personal about the laws of physics.
The meaning in life is not out there but inbetween our ears. In many ways this makes us the lords of creation.
When you are faced with the possibility of an early death, it makes you realize that life is worth living and that there are lots of things you want to do.
I'm very interested in film making. It's telling a story, fiction or non-fiction. I have been filmed quite a lot. Contrary to popular belief, filming isn't glamorous. It can be wearingly repetitious, as the same shot is taken over and over again.
It is a waste of time to be angry about my disability. One has to get on with life and I haven't done badly. People won't have time for you if you are always angry or complaining.
Any physical theory is always provisional, in the sense that it is only a hypothesis: you can never prove it.
Now, radical forward thinking is offering hope for the future: Replacement body parts to order. A team of scientists in California believe that if you can design them on a computer, you should be able to print them out.
Then we shall... be able to take part in the discussion of the question of why it is that we and the universe exist. If we find the answer to that, it would be the ultimate triumph of human reason -- for then we would know the mind of God.
Today, we commit to this next great leap into the cosmos because we're human, and our nature is to fly.
Bodies like the earth are not made to move on curved orbits by a force called gravity; instead, they follow the nearest thing to a straight path in a curved space, which is called a geodesic. A geodesic is the shortest (or longest) path between two nearby points.
It is tribute to how far we have come in theoretical physics that it now takes enormous machines and a great deal of money to perform experiments whose results we can not predict.
Because there is a law such as gravity, the Universe can and will create itself from nothing.
Because there is a law such as gravity, the Universe can and will create itself from nothing. Spontaneous creation is the reason there is something rather than nothing, why the Universe exists, why we exist. It is not necessary to invoke God to light the blue touch paper and set the Universe going.
Of course it is possible that UFO's really do contain aliens as many people believe, and the government is hushing it up.
The progress of the human race in understanding the universe has established a small corner of order in an increasingly disordered universe.
In effect, we have redefined the task of science to be the discovery of laws that will enable us to predict events up to the limits set by the uncertainty principle.
At times, I get very lonely because people are afraid to talk to me or don't wait for me to write a response. I'm shy and tongue-tied at times. I find it difficult to talk to people who I don't know.
In the last 200 years the population of our planet has grown exponentially, at a rate of 1.9% per year. If it continued at this rate, with the population doubling every 40 years, by 2600 we would all be standing literally shoulder to shoulder.
Mankind's greatest achievements have come about by talking and its greatest failures by not talking. It doesn't have to be like this.
Science fiction can be exciting and very gripping, but it doesn't tell us anything about the universe in which we live.
So great a contribution to physics was Two New Sciences that scholars have long maintained that the book anticipated Isaac Newton's laws of motion.
Before I lost my voice, it was slurred, so only those close to me could understand, but with the computer voice, I found I could give popular lectures. I enjoy communicating science. It is important that the public understands basic science, if they are not to leave vital decisions to others.
If we ever do find a complete theory of the universe, it would be a great triumph of human reason but it wouldn't leave much for us to do. We need an intellectual challenge.
I don't care much for equations myself. This is partly because it is difficult for me to write them down, but mainly because I don't have an intuitive feeling for equations.
Only in the few universes that are like ours would intelligent beings develop and ask the question: Why is the universe the way we see it? The answer is then simple: If it had been any different, we would not be here!
There is no prescribed route to follow to arrive at a new idea. You have to make the intuitive leap.
There is no prescribed route to follow to arrive at a new idea. You have to make the intuitive leap. But the difference is that once you've made the intuitive leap you have to justify it by filling in the intermediate steps. N my case, it often happens that I have an idea, but then I try to fill in the intermediate steps and find that they don't work, so I have to give it up.
It should soon be possible dramatically to increase the intelligence and life span of a few individuals. They and their offspring could become a master race. Evolution pays no regard to social justice. It was not fair on the Neanderthals they were replaced by modern humans.
I want to encourage public interest in space. I have never let my condition stop me. You only live once.
Our only chance of long-term survival is not to remain lurking on planet Earth, but to spread out into space.
There are no black holes -- in the sense of regimes from which light can't escape to infinity. There are however apparent horizons which persist for a period of time.
One could say: The boundary condition of the universe is that it has no boundary. The universe would be completely self-contained and not affected by anything outside itself. It would neither be created nor destroyed. It would just BE.
Many people do not like the idea that time has a beginning, probably because it smacks of divine intervention.
Many people do not like the idea that time has a beginning, probably because it smacks of divine intervention. (The Catholic Church, on the other hand, seized on the big bang model and in 1951 officially pronounced it to be in accordance with the Bible.
Just like a computer, we must remember things in the order in which entropy increases. This makes the second law of thermodynamics almost trivial. Disorder increases with time because we measure time in the direction in which disorder increases. You can't have a safer bet than that!
You cannot understand the glories of the universe without believing there is some Supreme Power behind it.
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.
If I had a time machine, I'd visit Marilyn Monroe in her prime or drop in on Galileo as he turned his telescope to the heavens.
So Einstein was wrong when he said, God does not play dice. Consideration of black holes suggests, not only that God does play dice, but that he sometimes confuses us by throwing them where they can't be seen.
Whether you want to uncover the secrets of the universe, or you just want to pursue a career in the 21st century, basic computer programming is an essential skill to learn.
So next time someone complains that you have made a mistake, tell him that may be a good thing. Because without imperfection, neither you nor I would exist.
The intelligent beings in these regions should therefore not be surprised if they observe that their locality in the universe satisfies the conditions that are necessary for their existence. It is a bit like a rich person living in a wealthy neighborhood not seeing any poverty.
For millions of years, mankind lived just like the animals. Then something happened which unleashed the power of our imagination. We learned to talk and we learned to listen.
For millions of years, mankind lived just like the animals. Then something happened which unleashed the power of our imagination. We learned to talk and we learned to listen. Speech has allowed the communication of ideas, enabling human beings to work together to build the impossible. Mankind's greatest achievements have come about by talking, and its greatest failures by not talking. It doesn't have to be like this. Our greatest hopes could become reality in the future. With the technology at our disposal, the possibilities are unbounded. All we need to do is make sure we keep talking.
There is no way that we can predict the weather six months ahead beyond giving the seasonal average.
One of the basic rules of the universe is that nothing is perfect. Perfection simply doesn't exist.....Without imperfection, neither you nor I would exist.
Science is beautiful when it makes simple explanations of phenomena or connections between different observations.
Remember to look up at the stars and not down at your feet. Try to make sense of what you see and wonder about what makes the universe exist. Be curious. And however difficult life may seem, there is always something you can do and succeed at.
It matters that you don't just give up.
According to 'M' theory, ours is not the only universe. Instead, 'M' theory predicts that a great many universes were created out of nothing.
If you believe in science, like I do, you believe that there are certain laws that are always obeyed.
I hope I have helped to raise the profile of science and to show that physics is not a mystery but can be understood by ordinary people.
The Planck satellite may detect the imprint of the gravitational waves predicted by inflation. This would be quantum gravity written across the sky.
I entered the health care debate in response to a statement in the United States press in summer 2009 which claimed the National Health Service in Great Britain would have killed me off, were I a British citizen. I felt compelled to make a statement to explain the error.
I had not expected 'A Brief History of Time' to be a best seller.
I had not expected 'A Brief History of Time' to be a best seller. It was my first popular book and aroused a great deal of interest. Initially, many people found it difficult to understand. I therefore decided to try to write a new version that would be easier to follow.
It was Einstein's dream to discover the grand design of the universe, a single theory that explains everything. However, physicists in Einstein's day hadn't made enough progress in understanding the forces of nature for that to be a realistic goal.
Throughout history, people have studied pure science from a desire to understand the universe rather than practical applications for commercial gain. But their discoveries later turned out to have great practical benefits.
I am in touch with a company that hopes to replicate my voice. However, they are not replicating my original voice -- if they did that, I would sound like a man in his 20s, which would be very strange! They are actually trying to replicate the synthesizer that sits on my wheelchair.
As scientists, we step on the shoulders of science, building on the work that has come before us -- aiming to inspire a new generation of young scientists to continue once we are gone.
The doctor who diagnosed me with ALS, or motor neuron disease, told me that it would kill me in two or three years.
I think the discovery of supersymmetric partners for the known particles would revolutionize our understanding of the universe.
Before 1915, space and time were thought of as a fixed arena in which events took place, but which was not affected by what happened in it. Space and time are now dynamic quantities... space and time not only affect but are also affected by everything that happens in the universe.
As Irving Good realised in 1965, machines with superhuman intelligence could repeatedly improve their design even further, triggering what Vernor Vinge called a 'singularity.'
Our minds work in real time, which begins at the Big Bang and will end, if there is a Big Crunch -- which seems unlikely, now, from the latest data showing accelerating expansion. Consciousness would come to an end at a singularity.
Theoretical physics is one of the few fields in which being disabled is no handicap -- it is all in the mind.
The voice I use is a very old hardware speech synthesizer made in 1986. I keep it because I have not heard a voice I like better and because I have identified with it.
We think we have solved the mystery of creation. Maybe we should patent the universe and charge everyone royalties for their existence.
Evolution has ensured that our brains just aren't equipped to visualise 11 dimensions directly. However, from a purely mathematical point of view it's just as easy to think in 11 dimensions, as it is to think in three or four.
I used to think information was destroyed in black hole. This was my biggest blunder, or at least my biggest blunder in science.
In Britain, like most of the developed world, stem-cell research is regarded as a great opportunity. America will be left behind if it doesn't change policy.
Why are we here? Where do we come from? Traditionally, these are questions for philosophy, but philosophy is dead.
We only have to look at ourselves to see how intelligent life might develop into something we wouldn't want to meet.
If we do discover a complete theory, it should be in time understandable in broad principle by everyone. Then we shall all, philosophers, scientists, and just ordinary people be able to take part in the discussion of why we and the universe exist.
The whole history of science has been the gradual realization that events do not happen in an arbitrary manner, but that they reflect a certain underlying order, which may or may not be divinely inspired.