Brief Answers to Big Questions
Author: Dr. Stephen Hawking
Why we must ask big questions
Real science can be far stranger than Sci Fi. Much more satisfying as well. Most people think real science is too complicated. People should try to appreciate basic fundamental principles without going too much to equations. People should rise to the challenge of sustainable development goals and act of out common interest.
Emission from black hole, now called Hawking radiation, proves that information is not lost in a black hole but it is not returned in a useful way, like burning an encyclopedia but retaining the smoke and the ashes.
Dr. Hawking uses a program called Acat, developed by Intel for speaking. He controls it by a small sensor via cheek movements.
A Brief History of Time, published on April Fool's day in 1988 became one of the best sellers of all time.
Howe can we provide solutions to the problems plaguing the earth? Overpopulation, poverty, global warming ? We need to work together to make the future a place we want to visit.
Be brave, be curious, be determined, overcome the odds. It can be done.
Is there a God
In 300 BCE, Aristarchus, a philosopher concluded that the eclipses were really shadow of earth passing over the moon and not a divine event. He deduced that earth was not the center of the universe and it orbits the sun.
Who created the Universe? We need mass(=energy as per Einstein equation) and space to create the universe. Space and energy were spontaneously created in an event called the Big Bang. How did something came out of nothing. This is explained by the concept of Negative Energy. When Big Band produced massive amount of positive energy, same amount of negative energy was produced and was stored in the space. Everything adds up to Zero.
Who triggered this whole process in the first place? At quantum level, particles behave differently. They can appear at random and vanish to appear somewhere else. Similarly universe , which would be tinier than a proton in the beginning, could have popped into existence without violating known laws of nature.
Nothing caused the Big Bang. Time stops there. There is no concept of space or time before the Big Bang, so there is no chance for a creator to have existed.
How did it all begin
Edwin Hubble discovered that many faint patches of light, called nebulae were vast galaxies of stars at a great distance. In order for them to appear so small and faint, the distances had to be so great that light from them would have taken billions of years to reach us. This indicated that beginning of the universe could not have been just a few thousand years ago. He also discovered that the galaxies are all moving away from each other. So based on this, age of universe is estimated to be about 10 to 15 billion years.
Discovery of microwaves gave observational evidence to beginning of universe theory. Einstein's general relativity breaks down at Big Bang. In classical theory, if one knows position and momentum of a particle, one can calculate where they would be at any other time, in past or future. However Werner Heisenberg gave the Uncertainty Principle, it is impossible to determine position or momentum of a subatomic particle at the same time. So we can only assign probabilities to future position and speeds of particles.
Similarly, we can assign probabilities to particular history of the universe. This was due to the work of Dr. Richard Feynman. Scientists are working to combine Einstein's theory of relativity and Feynman's idea of multiple histories into a complete unified theory.
Anthropic principle: Universe is the way we see it because if it were different there would not be anyone here to observe it.
Why do we have 3 dimensions? Why not 2 ? Because it would be difficult to swallow food if world were in 2D. Also with 3D you have inverse square law enabling gravitational forces to hold the planets together just fine. Else if it were inverse cube law, planets would fall into their sun or escape to outward darkness. Similarly electrons in the orbits would not be stable.
M-theory predicts that a great many universes were created out of nothing corresponding to many different possible histories. Hoping to prove this theory right at the Large Hadron Collider, at CERN in Geneva. Discovery of supersymmetric partners for known particles could revolutionize our understanding of the universe
Is there other intelligent life in the universe ?
A living being has 2 elements : a set of instructions that tell the system how to keep going and how to reproduce itself and a mechanism to carry out the instructions. Genes and metabolism.
After a minute after Big Bang, temperature falls to about a billion degrees when neutrons start decay to more protons. This resulted in Hydrogen, whose nucleus consists of a simple proton. Some neutrons collide with protons to form Helium. Universe continued to expand and cool and would have burned the original Hydrogen and Helium to form heavier elements like oxygen, carbon and iron.
Earth was formed largely out of these heavier elements. Somehow some of these atoms came to be arranged in the form of molecules of DNA. Francis Crick and James Watson discovered the famous double helix structure of DNA, with A-T, G-C base pairs. Each of the two chains act as a template to build further chains. DNA molecules can reproduce genetic information coded in their sequences of nucleic acid.
We do not know origin of DNA. One possibility is that RNA could have built up DNA. DNA passes info genetically, but now we pass info to next generation through writing. Genetic therapies can be carried out in this century to modify intelligence and instincts.
Why we have not been visited by aliens ? Probability of intelligent life is very low. Constant meteor attacks keep happening like the one which made dinosaurs extinct. Intelligent life tends to destory itself after it reaches certain stage. Also we may have been overlooked by other intelligent beings.
Can we predict the future ?
Max Planck showed that a hot body does not give all radiations at the same rate. Radiation comes only in packets or quanta of a certain size. Energy in quanta is higher for UV and X rays than for infra red or visible light. Thus, unless body is very hot, like the Sun, it will not have enough energy to give even a single quantum of X or UV rays.
Laplace told that we will be able to calculate position and speeds of particles at any time, if we know them at one time. Uncertainty principles disapproves of it. In quantum mechanics, position and speeds of a particle is given by wave function. A number at each point in space which gives the probability that the particle is found in that position. Rate at which wave function varies from point to point gives speed of the particle.
So in short, theoretically the laws allow us to predict the future but in practice the calculations are far too difficult.
What is inside a black hole ?
During many billions of years, a normal star will support itself against its own gravity by thermal pressure caused by the nuclear processes which convert hydrogen to helium. Eventually star will exhaust its nuclear fuel and will contract. They are called black holes. Gravity inside them is so strong that even light cannot escape them. Black hole has a boundary called event horizon. It is where gravity is just strong enough to drag light back and prevent it from escaping.
Black holes are characterized by their overall mass, electric charge and spin outside the event horizon. Here, gravity is strong, space-time is violently distorted.
Black holes emit particles and radiation like an ordinary hot body. A mountain sized black holes would give off X-rays and gamma rays. It may be possible to create micro black holes at the Large Hadron Collider at CERN in Switzerland. It consists of a circular tunnel, 27 km long. Two beams of particles travel around this tunnel in opposite directions and are made to collide. Radiating particles because of this might be easy to recognise.
To understand whether information is really lost in black holes is one of the biggest unresolved problems in theoretical physics.
Is Time Travel possible ?
According to Euclidean geometry, sides of the triangle add up to 180 degrees. However other forms of geometry are possible in which this is not the case. Triangle on surface of the earth, for example.
For time travel we need a spaceship which travels faster than light. Space and time are warped, so the question of time travel is one of whether we can make space-time so warped that one can go back to the past. Wormholes are a way to do that, like in the movie Interstellar. But there are lot of paradoxes. Like what if you go back and kill your parents before you are born ?
Chronology Protection Conjecture: Laws of physics conspire to prevent time travel on a macroscopic scale. However there is hope that M-theory would throw up some exciting possibilities.
Will we survive on earth ?
Earth is becoming too small for us. Lot of problems like deforestation, over population, global warming etc are haunting us. Nuclear arms race also poses a huge problem. It is almost inevitable that either a nuclear confrontation or environmental catastrophe will strike the earth in next 1000 years, which as geological time goes is the mere blink of an eye. So we need to find ways to explore other homes in the universe and dont depend completely on earth.
Human race needs to improve its mental and physical qualities if it needs to deal with the increasingly complex world around it and meet new challenges like space travel. It also needs to increase its complexity if biological systems are to keep ahead of electronic ones. Genetic engineering on humans to improve the DNA can be one such example.
Should we colonise space ?
On 20 July 1969, Buzz Aldrin and Neil Armstrong landed on the moon. It changed the future of the human race. It helped create a fascination with science and accelerated technological progress. Need to have a similar event now to rekindle the spirits. Elon Musk announced SpaceX plans for a lunar base and a Mars mission by 2022.
Moon and Mars are the most suitable sites for space colonies in the solar system. Mercury and Venus are too hot, while Jupiter and Saturn are gas giants with no solid surface. What about outside the solar system ? Proxima b is closest to earth but about 4.5 light years away and orbits Proxima Centauri. Recent research indicates it is similar to earth. Travelling there takes 70000 years with current technology.
Breakthrough Starshot is a real opportunity for man to make early forays into outer space. Its a POC misson and works on 3 concepts: miniaturised spacecraft, light propulsion and phase locked lasers. The Star Chip, a fully functional space probe reduce to a few centimeters in size, will be attached to a light sail. Made from meta materials, the light sail weighs no more than few grams. It is envisaged that a thousand Star Chips and light sails, the nanocraft, will be sent into Orbit. On the ground, an array of lasers at the kilometer scale will combine into a single, very powerful light beam. The beam is fired through atmosphere, striking the sails in space with tens of gigawatts of power. Such a system could reach Mars in less than an hour, reach Pluto in days and reach Alpha Centauri in just over 20 years.
Lot of engineering challenges are present in such a design though. In conclusion we can say that if we find a planet in Alpha Centauri, its image, captured by a camera travelling at a fifth of light speed will be heavily distorted due to the effects of relativity. As a species we need to find ways to explore other homes apart from mother earth.
Will Artificial Intelligence outsmart us ?
Intelligence is central to what it means to be human.DNA passes blueprints of life between generations. At some point in our cosmic history, we became conscious.
Due to computing progress because of the Moore's law AI has had remarkable success in speech recognition, image classification, autonomous vehicles, machine translation, legged locomotion and question-answering systems.
AI has a lot of potential. Its success would be the biggest event in human history. It might also be the last, unless we learn how to avoid the risks.Tech pioneers Bill Gates, Steve Wozniak and Elon Musk have echoed this concern and healthy culture of risk assessment and awareness of societal implications is beginning to take root in the AI community. Elon Musk and Dr.Hawking sit on the scientific advisory board for the Future of Life Institute, an organization working to mitigate existential risks facing humanity.
World has been changing incredibly fast as people, devices and information are increasingly connected to each other. Computational power is growing and quantum computing is quickly being realised. It ill change even human biology. There is already one technique to edit DNA precisely, called CRISPR. The basis of this is a bacterial defense system It can accurately target and edit stretches of genetic code.
When we invented fire, we messed up repeatedly, then invented fire extinguisher. With more powerful technologies such as nuclear weapons, synthetic biology and strong AI, we should plan ahead and aim to get things right the first time, because it may be the only chance we get.
How do we shape the future ?
Gravitational wavers were observed in 2016 by the LIGO experiment, which confirmed Einstein theory about space, time, energy and matter. Einstein had the ability to look beyond the surface to reveal the underlying structure. He was undaunted by common sense, the idea that things must be the way they seemed. He had the courage to pursue ideas that seemed absurd to others. This set him free to be ingenious. Key element of him was imagination.
Human mind is incredible. It can conceive magnificence of heavens and intricacies of basic components of matter. It needs a spark of enquiry and wonder which often comes from a teacher.
Every individual should be familiar with and confident around scientific subjects, whatever they choose to do. They need to be scientifically literate and inspired to engage with developments in science and technology in order to learn more. A world where only a tiny super-elite are capable of understanding advanced science is dangerous.
So 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 dont just give up. Unleash your imagination. Shape the future.
Why we must ask big questions
Real science can be far stranger than Sci Fi. Much more satisfying as well. Most people think real science is too complicated. People should try to appreciate basic fundamental principles without going too much to equations. People should rise to the challenge of sustainable development goals and act of out common interest.
Emission from black hole, now called Hawking radiation, proves that information is not lost in a black hole but it is not returned in a useful way, like burning an encyclopedia but retaining the smoke and the ashes.
Dr. Hawking uses a program called Acat, developed by Intel for speaking. He controls it by a small sensor via cheek movements.
A Brief History of Time, published on April Fool's day in 1988 became one of the best sellers of all time.
Howe can we provide solutions to the problems plaguing the earth? Overpopulation, poverty, global warming ? We need to work together to make the future a place we want to visit.
Be brave, be curious, be determined, overcome the odds. It can be done.
Is there a God
In 300 BCE, Aristarchus, a philosopher concluded that the eclipses were really shadow of earth passing over the moon and not a divine event. He deduced that earth was not the center of the universe and it orbits the sun.
Who created the Universe? We need mass(=energy as per Einstein equation) and space to create the universe. Space and energy were spontaneously created in an event called the Big Bang. How did something came out of nothing. This is explained by the concept of Negative Energy. When Big Band produced massive amount of positive energy, same amount of negative energy was produced and was stored in the space. Everything adds up to Zero.
Who triggered this whole process in the first place? At quantum level, particles behave differently. They can appear at random and vanish to appear somewhere else. Similarly universe , which would be tinier than a proton in the beginning, could have popped into existence without violating known laws of nature.
Nothing caused the Big Bang. Time stops there. There is no concept of space or time before the Big Bang, so there is no chance for a creator to have existed.
How did it all begin
Edwin Hubble discovered that many faint patches of light, called nebulae were vast galaxies of stars at a great distance. In order for them to appear so small and faint, the distances had to be so great that light from them would have taken billions of years to reach us. This indicated that beginning of the universe could not have been just a few thousand years ago. He also discovered that the galaxies are all moving away from each other. So based on this, age of universe is estimated to be about 10 to 15 billion years.
Discovery of microwaves gave observational evidence to beginning of universe theory. Einstein's general relativity breaks down at Big Bang. In classical theory, if one knows position and momentum of a particle, one can calculate where they would be at any other time, in past or future. However Werner Heisenberg gave the Uncertainty Principle, it is impossible to determine position or momentum of a subatomic particle at the same time. So we can only assign probabilities to future position and speeds of particles.
Similarly, we can assign probabilities to particular history of the universe. This was due to the work of Dr. Richard Feynman. Scientists are working to combine Einstein's theory of relativity and Feynman's idea of multiple histories into a complete unified theory.
Anthropic principle: Universe is the way we see it because if it were different there would not be anyone here to observe it.
Why do we have 3 dimensions? Why not 2 ? Because it would be difficult to swallow food if world were in 2D. Also with 3D you have inverse square law enabling gravitational forces to hold the planets together just fine. Else if it were inverse cube law, planets would fall into their sun or escape to outward darkness. Similarly electrons in the orbits would not be stable.
M-theory predicts that a great many universes were created out of nothing corresponding to many different possible histories. Hoping to prove this theory right at the Large Hadron Collider, at CERN in Geneva. Discovery of supersymmetric partners for known particles could revolutionize our understanding of the universe
Is there other intelligent life in the universe ?
A living being has 2 elements : a set of instructions that tell the system how to keep going and how to reproduce itself and a mechanism to carry out the instructions. Genes and metabolism.
After a minute after Big Bang, temperature falls to about a billion degrees when neutrons start decay to more protons. This resulted in Hydrogen, whose nucleus consists of a simple proton. Some neutrons collide with protons to form Helium. Universe continued to expand and cool and would have burned the original Hydrogen and Helium to form heavier elements like oxygen, carbon and iron.
Earth was formed largely out of these heavier elements. Somehow some of these atoms came to be arranged in the form of molecules of DNA. Francis Crick and James Watson discovered the famous double helix structure of DNA, with A-T, G-C base pairs. Each of the two chains act as a template to build further chains. DNA molecules can reproduce genetic information coded in their sequences of nucleic acid.
We do not know origin of DNA. One possibility is that RNA could have built up DNA. DNA passes info genetically, but now we pass info to next generation through writing. Genetic therapies can be carried out in this century to modify intelligence and instincts.
Why we have not been visited by aliens ? Probability of intelligent life is very low. Constant meteor attacks keep happening like the one which made dinosaurs extinct. Intelligent life tends to destory itself after it reaches certain stage. Also we may have been overlooked by other intelligent beings.
Can we predict the future ?
Max Planck showed that a hot body does not give all radiations at the same rate. Radiation comes only in packets or quanta of a certain size. Energy in quanta is higher for UV and X rays than for infra red or visible light. Thus, unless body is very hot, like the Sun, it will not have enough energy to give even a single quantum of X or UV rays.
Laplace told that we will be able to calculate position and speeds of particles at any time, if we know them at one time. Uncertainty principles disapproves of it. In quantum mechanics, position and speeds of a particle is given by wave function. A number at each point in space which gives the probability that the particle is found in that position. Rate at which wave function varies from point to point gives speed of the particle.
So in short, theoretically the laws allow us to predict the future but in practice the calculations are far too difficult.
What is inside a black hole ?
During many billions of years, a normal star will support itself against its own gravity by thermal pressure caused by the nuclear processes which convert hydrogen to helium. Eventually star will exhaust its nuclear fuel and will contract. They are called black holes. Gravity inside them is so strong that even light cannot escape them. Black hole has a boundary called event horizon. It is where gravity is just strong enough to drag light back and prevent it from escaping.
Black holes are characterized by their overall mass, electric charge and spin outside the event horizon. Here, gravity is strong, space-time is violently distorted.
Black holes emit particles and radiation like an ordinary hot body. A mountain sized black holes would give off X-rays and gamma rays. It may be possible to create micro black holes at the Large Hadron Collider at CERN in Switzerland. It consists of a circular tunnel, 27 km long. Two beams of particles travel around this tunnel in opposite directions and are made to collide. Radiating particles because of this might be easy to recognise.
To understand whether information is really lost in black holes is one of the biggest unresolved problems in theoretical physics.
Is Time Travel possible ?
According to Euclidean geometry, sides of the triangle add up to 180 degrees. However other forms of geometry are possible in which this is not the case. Triangle on surface of the earth, for example.
For time travel we need a spaceship which travels faster than light. Space and time are warped, so the question of time travel is one of whether we can make space-time so warped that one can go back to the past. Wormholes are a way to do that, like in the movie Interstellar. But there are lot of paradoxes. Like what if you go back and kill your parents before you are born ?
Chronology Protection Conjecture: Laws of physics conspire to prevent time travel on a macroscopic scale. However there is hope that M-theory would throw up some exciting possibilities.
Will we survive on earth ?
Earth is becoming too small for us. Lot of problems like deforestation, over population, global warming etc are haunting us. Nuclear arms race also poses a huge problem. It is almost inevitable that either a nuclear confrontation or environmental catastrophe will strike the earth in next 1000 years, which as geological time goes is the mere blink of an eye. So we need to find ways to explore other homes in the universe and dont depend completely on earth.
Human race needs to improve its mental and physical qualities if it needs to deal with the increasingly complex world around it and meet new challenges like space travel. It also needs to increase its complexity if biological systems are to keep ahead of electronic ones. Genetic engineering on humans to improve the DNA can be one such example.
Should we colonise space ?
On 20 July 1969, Buzz Aldrin and Neil Armstrong landed on the moon. It changed the future of the human race. It helped create a fascination with science and accelerated technological progress. Need to have a similar event now to rekindle the spirits. Elon Musk announced SpaceX plans for a lunar base and a Mars mission by 2022.
Moon and Mars are the most suitable sites for space colonies in the solar system. Mercury and Venus are too hot, while Jupiter and Saturn are gas giants with no solid surface. What about outside the solar system ? Proxima b is closest to earth but about 4.5 light years away and orbits Proxima Centauri. Recent research indicates it is similar to earth. Travelling there takes 70000 years with current technology.
Breakthrough Starshot is a real opportunity for man to make early forays into outer space. Its a POC misson and works on 3 concepts: miniaturised spacecraft, light propulsion and phase locked lasers. The Star Chip, a fully functional space probe reduce to a few centimeters in size, will be attached to a light sail. Made from meta materials, the light sail weighs no more than few grams. It is envisaged that a thousand Star Chips and light sails, the nanocraft, will be sent into Orbit. On the ground, an array of lasers at the kilometer scale will combine into a single, very powerful light beam. The beam is fired through atmosphere, striking the sails in space with tens of gigawatts of power. Such a system could reach Mars in less than an hour, reach Pluto in days and reach Alpha Centauri in just over 20 years.
Lot of engineering challenges are present in such a design though. In conclusion we can say that if we find a planet in Alpha Centauri, its image, captured by a camera travelling at a fifth of light speed will be heavily distorted due to the effects of relativity. As a species we need to find ways to explore other homes apart from mother earth.
Will Artificial Intelligence outsmart us ?
Intelligence is central to what it means to be human.DNA passes blueprints of life between generations. At some point in our cosmic history, we became conscious.
Due to computing progress because of the Moore's law AI has had remarkable success in speech recognition, image classification, autonomous vehicles, machine translation, legged locomotion and question-answering systems.
AI has a lot of potential. Its success would be the biggest event in human history. It might also be the last, unless we learn how to avoid the risks.Tech pioneers Bill Gates, Steve Wozniak and Elon Musk have echoed this concern and healthy culture of risk assessment and awareness of societal implications is beginning to take root in the AI community. Elon Musk and Dr.Hawking sit on the scientific advisory board for the Future of Life Institute, an organization working to mitigate existential risks facing humanity.
World has been changing incredibly fast as people, devices and information are increasingly connected to each other. Computational power is growing and quantum computing is quickly being realised. It ill change even human biology. There is already one technique to edit DNA precisely, called CRISPR. The basis of this is a bacterial defense system It can accurately target and edit stretches of genetic code.
When we invented fire, we messed up repeatedly, then invented fire extinguisher. With more powerful technologies such as nuclear weapons, synthetic biology and strong AI, we should plan ahead and aim to get things right the first time, because it may be the only chance we get.
How do we shape the future ?
Gravitational wavers were observed in 2016 by the LIGO experiment, which confirmed Einstein theory about space, time, energy and matter. Einstein had the ability to look beyond the surface to reveal the underlying structure. He was undaunted by common sense, the idea that things must be the way they seemed. He had the courage to pursue ideas that seemed absurd to others. This set him free to be ingenious. Key element of him was imagination.
Human mind is incredible. It can conceive magnificence of heavens and intricacies of basic components of matter. It needs a spark of enquiry and wonder which often comes from a teacher.
Every individual should be familiar with and confident around scientific subjects, whatever they choose to do. They need to be scientifically literate and inspired to engage with developments in science and technology in order to learn more. A world where only a tiny super-elite are capable of understanding advanced science is dangerous.
So 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 dont just give up. Unleash your imagination. Shape the future.
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