Brief answers to the big questions by Stephen Hawking

"Brief answers to the big questions" by Stephen Hawking- Everyone should read. 

This book is published by John Murray in 2018 and has 256 pages.

Book starts with authors note titled 'Why we must ask big questions'. This is one of the longest Author's note, as compared to the book size,  I have ever read.

Book summary

Stephen Hawking answers following questions. 

Is there a God?

My work is not proving or disproving existence of God, it's finding a rational framework to understand the universe around us. One could define God as embodiment of laws of nature. Universe was spontaneously created out of nothing, according to the laws of science. Three ingredients are needed to create universe. Matter, Energy and Space. Space is a vast store of negative energy that balances positive energy. So if universe adds up to nothing, you don't need God to create it. Time didn't exist before the Big Bang so there is no time for God to make the universe in. There is no God, so there is no heaven and afterlife either. 

How did it all begin?

Hubble discovered that universe is expanding. From the present rate of expansion we can estimate that universe might have started 10 to 15 billion years ago. Roger Penrose and author proved that universe must have a beginning. Scientists are now working to combine Einstein's general theory of relativity and Feynman's idea of multiple histories into a complete unified theory that will describe everything that happens in the universe. 

Is there other intelligent life in the universe?

Development of language meant that information could be passed on from generation to generation, other than genetically through DNA. There was an exponential rate of growth of knowledge in last 300 years, but human brain is evolving at Darwinian pace. This is beginning to cause problem forcing to focus on specific knowledge area and hence specialization. Next step of evolution will be genetically engineered humans or self designing beings. Machines sent to other planets can produce more machines there. These machines would be new form of life. Probability of life spontaneously appearing is so low that earth may be the only planet on which it happened. Another possibility is that life appeared on another planet but did not evolve intelligence. There may have been intelligent life on other planet and it may have self destroyed. There may be intelligent life out there, but that we have been overlooked. 

Can we predict the future?

French scientist Laplace said if at one time we knew the positions and speeds of all the particles in the universe, then we would be able to calculate their behaviour at any time in the past or future. But Heisenberg's Uncertainty Principle comes into play. Quantum mechanics allowed concept of wave function that provides a range of possibilities. So the answer is that in principle, laws allow us to predict the future, but in practice the calculations are often too difficult. 

What is inside a Black hole?

For many billion years any star will support itself against its own gravity by thermal pressure caused by nuclear processes which convert hydrogen to helium. Eventually the star will contract and either become a dwarf star or collapse. This star will contract to a single point of infinite density called singularity and become a black hole. Black hole is a region where gravity is so strong that light cannot escape. Boundary of black hole is called event horizon. Author proved that black hole emits thermal radiation. Author ruminates, on the lighter side, that if mini black holes were found he would have got Nobel Prize. Work is still on to determine if the information is lost in black hole or it can be retrieved.

Is time travel possible?

For Time Travel you need to travel faster than light and Einstein showed that it would take infinite amount of power to accelerate past the speed of light. If time travel will be possible in future, why hasn't someone come back from the future to tell us how to do it. Author thinks that the sum-over-histories idea supports the consistent-histories hypothesis rather than the alternative-histories idea. In conclusion, travel back in time can't be ruled out according to our present understanding.

Will we survive on earth?

Physical resources of Earth are being drained at an alarming rate. We stand on the brink of Second Nuclear Age and a period of unprecedented climate change. A nuclear confrontation or environmental catastrophe will cripple the earth at some point in the next 1000 years. World population has jumped from 1 billion to 7.6 billion in last 200 years. Human genetic engineering is likely to happen in the next Millennium, whether we want it or not. Our present computers are less complex than the brain of an earthworm. It's time to explore other solar systems.

Should we colonise space?

Spreading out into space will completely change the future of the human race, and maybe determine whether we have any future at all. We need to increase the world budget for space. Elon Musk announced SpaceX plans for a lunar base and a Mars mission by 2022. Author fears that the human race is not going to have a future if we don't go into space. The Moon and Mars are the most suitable sites for space colonies in the solar system. Europa, a moon of Jupiter, and Titan, a moon of Saturn, are probables. Planet Proxima b in the solar system Alpha Centauri has some similarities to earth. With current Technology interstellar travel is utterly impractical. Cosmos is where our ultimate destiny lies.

Will artificial intelligence (AI) outsmart us?

If computers continue to obey Moore's law, doubling the speed and memory capacity every 18 months, computers are likely to overtake humans in intelligence in the next 100 years. Success in creating AI would be the biggest event in human history, it might also be the last unless we learn how to avoid the risks. Short term impact of AI depends on who controls it, the long term impact depends on whether it can be controlled at all. Fortunately a healthy culture of risk assessment and awareness of societal implications is beginning to take root in the AI community. Author and Elon Musk have written an open letter in which they say: we should concentrate research on how we could prevent potential problems while also reaping potential benefits AI offers us. Our future is a race between the growing power of our technology and wisdom with which we use it. Let's make sure that wisdom wins.

How do we shape the future?

If you look behind every exceptional person there is an exceptional teacher. The basis for future of education must lie in schools and inspiring teachers. There are big questions still to answer and much work lies ahead but we know more now and have achieved more in this relatively short space of time. There are two options for the future of humanity, exploration of space and artificial intelligence. So remember to look at the stars and not down at your feet. Be curious. Unleash your imagination. Shape the future.

End of book summary

Author's thoughts about teacher are very similar to the Hindu teachings that gives immense importance to Guru or teacher.

The questions chosen by author are very pertinent, interesting and ones that a common man is interested in. Author does his best to explain the science behind it without entangling into scientific jargon. He also uses analogies from our daily life to explain the scientific phenomenon. However, some readers may still find certain portions hard to understand because of the complexity of subject. Nevertheless, author needs to be applauded for daring to handle these subjects in a popular book rather than a scientific one. 

While answering one question author invariably touches another question (e.g. God, AI, quantum mechanics) due to the commonalities and overlapping science.

This book was incomplete at the time of his death and has been completed based on his personal archives in collaboration with his academic colleagues, his family and Stephen Hawking estate. Foreword of this Book is written by Eddie Redmyne who played the role of author in the film 'The theory of everything'. Introduction to this book is by Kip S. Thorne (Gravitational waves fame Noble laureate), his friend and a accomplished scientist himself. Afterword is by Lucy Hawking, author's daughter. 

Stephen Hawking was a genius who's body was rendered immobile by motor neuron disease. Surpassing his limits and endurance is an epitome of his perseverance. He had a razor sharp mind. Unfortunately he will never receive noble prize as it is not given posthumously. 

Why did I read this book? Author.

What I didn't like? Nil. 

What did I like? His intention to bring science to masses.

Read if you are interested in science and even if you are not.