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Appassionante, divulgativo, essenziale

Come tutti i libri dello stesso autore..."facile" da leggere e che e' divulgativo davvero.

Recensito in Italia il 8 gennaio 2023

lovely

Recensito in Italia il 8 luglio 2023

Da leggere in lingua originale. Hawking spiega in modo estremamente brillante (e mai noiosa) l'evoluzione delle teorie cosmologiche. Tanti esempi, altrettanta ironia, nulla dato per scontato (ma una buona cultura generale è necessaria per capirlo a fondo).

Recensito in Italia il 29 dicembre 2019

Un gran bel tributo ad uno dei più influenti uomini della storia moderna. Ottimo il contenuto ed ottima l'impaginazione.

Una persona l'ha trovato utile

Piera

Libro

Recensito in Italia il 23 marzo 2021

Libro

Una persona l'ha trovato utile

The Klingon

Great!

Recensito in Italia il 17 marzo 2019

A book that everyone have to read. Such a great mind, such a great man, such a great scientist. Pure light.

5 persone l'hanno trovato utile

Chiara

Grandioso

Recensito in Italia il 6 maggio 2019

Grandioso nella sua semplicità. Riesce a spiegare concetti complessi in maniera accessibile. Oltre ad essere un esempio con la sua vita

4 persone l'hanno trovato utile

Paolo

Bel libro

Recensito in Italia il 12 aprile 2020

Bello da leggere

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Steven H Propp

A POSTHUMOUS WORK, CONSOLIDATING AND SUMMARIZING HAWKING’S VIEWS

Recensito negli Stati Uniti il 3 maggio 2022

The publisher noted in this 2018 book, “Stephen Hawking was regularly asked for his thoughts of the ‘big questions’ of the day… Stephen maintained an enormous personal archive of his responses, which took the form of speeches, interviews and essays. This book draws from this personal archive and was in development at the time of his death. It has been completed in collaboration with his academic colleagues, his family and the Stephen Hawking Estate.”

In the first chapter, Hawking explained, “People have always wanted answers to the big questions…I am a scientist… I have spent my life traveling across the universe, inside my mind… I have sought to answer some of the big 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… most people can understand and appreciate the basic ideas if they are presented in a clear way without equations…” (Pg. 4)

He states, “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 a God?... One could define God as the embodiment of the laws of nature. However, this is not what most people would think of as God. They mean a … being, with whom one can have a personal reliationship… I use the word ‘God’ in an impersonal sense … 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 … should soon provide a definitive answer to how the universe began… I think the universe was spontaneously created out of nothing, according to the laws of science.” (Pg. 28-29)

He adds, “When the Big Bang produced a massive amount of positive energy, it simultaneously produced the same amount of negative energy. In this way, the positive and the negative add up to zero…So what does this mean in our quest to find out if there is a God? It means that if the universe adds up to nothing, then you don’t need a God to create it. The universe is the ultimate free lunch.” (Pg. 33) He continues, “The laws of nature itself tell us that not only could the universe have popped into existence without any assistance… but also that it is possible that nothing caused the Big Bang. Nothing.” (Pg. 35)

He summarizes, “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 my view that the simplest explanation is that there is no God. No one created the universe and no one directs our fate… there is probably no heaven and afterlife wither. I think belief in an afterlife is just wishful thinking… We have this one life in which to appreciate the grand design of the universe, and for that I am extremely grateful.” (Pg. 38)

He recounts, “the theorems Roger Penrose and I proved … indicated that the universe began in a Big Bang, a point where the whole universe and everything in it were scrunched up into a single point of infinite density, a space-time singularity. At this point Einstein’s general theory of relativity would have broken down. Thus one cannot use it to predict in what manner the universe began. One is left with the origin of the universe apparently being beyond the scope of science… That the universe began with a singularity was not an idea that I or a number of other people were happy with.” (Pg. 50-51)

He notes, “M-theory, which is our best candidate for a complete unified theory, allows a very large number of possible histories for the universe. Most of these histories are quite unsuitable for the development of intelligent life. Either they are empty… or wrong in some other way. Yet, according to Richard Feynman’s multiple-histories idea, these uninhabited histories might have quite a high probability. We really don’t care how many histories there may be that don’t create intelligent beings. We are interested only in the subject of histories in which intelligent life develops. This intelligent life need no be anything like humans. Little green men would do as well…” (Pg. 56-57)

He asserts, “We are the product of quantum fluctuations in the very early universe. God really does play dice.” (Pg. 61) He continues, “There may be other universes. M-theory predicts that a great many universes were created out of nothing, corresponding to the many different possible histories… There is still hope that we see the first evidence for M-theory at the LHC particle accelerator… at CERN in Geneva… I think the discovery of supersymmetric partners for the known particles would revolutionize our understanding of the universe… There is still some hope that the LHC will discover supersymmetry. Bus supersymmetry might still be found in the next generation of accelerators … So there may well be other universes, but unfortunately we will never be able to explore them.” (Pg. 62-63)

He acknowledges, “That carbon atoms should exist at all, with the properties that they have, requires a fine adjustment of physical constants… If these constants had significantly different values, either the nucleus of the carbon atom would not be stable or the electrons would collapse in on the nucleus. At first sight, it seems remarkable that the universe is so finely tuned. Maybe this is evidence that the universe was specially designed to produce the human race. However, one has to be careful about such arguments, because of the Anthropic Principle, the idea that our theories about the universe must be compatible with our own existence. This is based on the self-evident truth that if the universe had not been suitable for life we wouldn’t be asking why it is so finely tuned.” (Pg. 69-70)

He continues, “One can apply the Anthropic Principle in either its Strong or Weak versions. For the Strong Anthropic Principle, one supposes that there are many different universes, each with different values of the physical constants. In a small number, the values will allow the existence of objects like carbon atoms. Since we must live in one of these universes, we should not be surprised that the physical constraints are finely tuned. If they weren’t, we wouldn’t be here. The Strong form of the Anthropic Principle is thus not very satisfactory, because what operational meaning can one give to the existence of all those other universes? And if they are separate from our own universe, how can what happens in them affect our universe? Instead, I shall adopt … the Weak Anthropic Principle. That is, I shall take the values of the physical constraints as given.” (Pg. 70)

He suggests, “The early appearance of life on Earth suggests that there is a good chance of the spontaneous generation of life in suitable conditions… Short lengths of RNA could reproduce themselves like DNA, and might eventually build up to DNA. We cannot make nucleic acids in the laboratory from non-living material, let alone RNA. But given 500 million years, and oceans covering most of the Earth, there might be a reasonable probability of RNA being made by chance.” (Pg. 75)

He points out, “According to the theory of relativity, nothing can travel faster than light, so a round trip to the nearest star would take at least eight years… In science fiction, they overcome this difficulty by space warps, or travel through extra dimensions. But I don’t think these will ever be possible, no matter how intelligent life becomes.” (Pg. 82)

He asks, “What are the chances that we will encounter some alien forms of life as we explore the galaxy?... there ought to be many other stars whose planets have life on them. Some of these stellar systems could have formed five billion years before the Earth---so why is the galaxy not crawling with self-designing mechanical or biological forms? Why hasn’t the Earth been visited and even colonized?... Maybe the probability of life spontaneously appearing is so low that Earth is the only planet in the … observable universe----on which it happened. Another possibility is that… most of these forms of life did not evolve intelligence.” (Pg. 83)

He explains, “Einstein’s paper of 1905 seemed to rule out time travel into the past. It also indicated that space travel to other stars was going to be a very slow and tedious business… If the spaceship went very near the speed of light it might seem to the people on board that the trip to the galactic centre had taken only a few years. But that wouldn’t be much consolation if everyone you had known had died… thousands of years ago when you got back. That wouldn’t be much god for science-fiction novels either…” (Pg. 130)

He suggests, “Closely related to time travel is the ability to travel rapidly from one position in space to another… the only way to get from one side of the gallery to the other in a reasonable time would seem to be if we could warp space-time so much that we created a little tube or wormhole. This could connect the two sides of the galaxy and act as a short cut to get from one to the other and back while your friends were still alive. Such wormholes have been seriously suggested as being within the capabilities of a future civilization. But if you can travel from one side of the galaxy to the other in a week or two you could go back through another wormhole and arrive back before you had set out…” (Pg. 133-134)

He notes, “it might seem that as we advance in science … we might be able to … warp space and time in some … way so as to be able to travel into our past. If this were the case it would raise a whole host of questions and problems. One of these is if time travel will be possible in the future, why hasn’t someone come back from the future to tell us how to do it… Of course, some people would claim that we have already been visited from the future. They would say that UFOs come from the future and that governments are engaged in a gigantic conspiracy to cover them up and keep for themselves the scientific knowledge that these visitors bring. All I can say is that if governments were hiding something they are doing a poor job of extracting useful information from the aliens… once you admit that some [UFO reports] are mistakes or hallucinations, isn’t it more probable that they all are than that we are being visited by people from the future or from the other side of the galaxy?” (Pg. 137-138)

He continues, “A possible way to reconcile time travel… would be to say that such travel can occur only in the future. In this view own would say space-time is our past was fixed because we have observed it and seen that it is not warped enough to allow travel into the past. On the other hand the future is open… This picture… would still have plenty of paradoxes… like going back and killing your parents before you were born… There seem to be two possible resolutions. One is what I shall call the consistent-histories approach… On this view… it would imply that we were completely determined: we couldn’t change our minds. So much for free will. The other possibility is what I call the alternative-histories approach… [whereby] the universe has every single possible history, each with its own probability… But each history is complete and self-contained… So a rocket cannot transfer to another alternative history when it comes around again… It thus seems that we are stuck with the consistent-histories picture…” (Pg. 138-140)

He concludes, “According to … M-theory… space-time ought to have eleven dimensions… seven of these dimensions are curled up in a space so small that we don’t notice them… If this picture is correct it might be possible to arrange that the four flat dimensions get mixed up with the seven highly curved or warped dimensions. What this would give rise to we don’t yet know. But it opens exciting possibilities. In conclusion, rapid space travel and travel back in time can’t be rules out according to our present understanding. They would create great logical problems, so let’s hope there’s a Chronology Protection Law to prevent people going back and killing their parents. But science-fiction fans need not lose heart. There’s hope in M-theory.” (Pg. 142)

He suggests, “the rapid pace of improvement will probably continue until computers have a similar complexity to the human brain. Some people say that computers can never show true intelligence, whatever that may be. But it seems to me that if very complicated chemical molecules can operate in humans to make them more intelligent, then equally complicated electronic circuits can also make computers act in an intelligent way. And if they are intelligent they can presumably design computers that have even greater complexity and intelligence.” (Pg. 161)

This book will be absolute ‘MUST READING’ for anyone even remotely interested in scientific approaches to such questions.

34 persone l'hanno trovato utile

Richard L.

It's Steven Hawkins, what more do you need to know?

Recensito nel Regno Unito il 27 giugno 2023

To be honest even if it was rubbish I would still have wanted to read it, these are the last words of a great man. But it is was a good read anyway.

People who have given this a low review fall into 3 camps,

Firstly those that found a collection of disconnected articles. To be honest, they have a point, but it does say that in the description so it seems a bit unfair to criticise something for being what it claims to be. In any case, each one of the disconnected articles does stand up well, some are of course better than others, those on cosmology standout but the more speculative ones on aliens and AI are of course less authoritative but nevertheless, I am interested in what the great man has to say on them.

Secondly, some reviewers seem concerned that his celebrity status gives him more public credibility than his academic standing warrants. I have no idea if that has any merit or not, but either way, his academic credibility is high (he had the same position in Cambridge as Newton and Dirac). The fact that he was a man of great personal strength and a wonderful communicator in no way diminishes his intellectual greatness.

And thirdly a few people are unhappy with his non-scientific views, especially those on Brexit. Frankly, I think he has as much right to an opinion on those matters as anyone and a good deal more credibility than many politicians.

Thoroughly good read and thought-provoking.

3 persone l'hanno trovato utile

Dave Weber

Surprisingly easy read

Recensito negli Stati Uniti il 9 settembre 2023

Not only was it entertaining but also educational. I actually learned some things while other things were hard to wrap my head around. Hawking was an amazing man with a great sense of humor. The world has lost a very special person who will be hard to replace. I've never really been into science but I really enjoyed this book. If you're looking for insight into the major challenges facing the world today you should read this book.

Una persona l'ha trovato utile

Jason

Wonderful work (... and @Diane)

Recensito negli Stati Uniti il 21 ottobre 2018

I loved this book! Any fan of Hawking's work should enjoy it, for sure. I really liked the "pondering" and "musing" pace and feel. I'd recommend it to anyone.

@Diane... Whenever I encounter something to which I feel the need to respond, I’m usually pretty good at keeping my emotions at bay, and I sincerely try to (and, usually do) keep my cool, put myself into the other person’s shoes and think about my rebuttals logically. Over the years I’ve always felt a little guilty because, even though I’m amicable and nice most of the time, I just feel bad when I make someone else feel bad, regardless of how correct I might feel that I am. After seeing your comment, however, I really have to say congratulations… you’ve convinced me that I really shouldn’t be so hard on myself.

Pathetic? I guess our definitions are a tad juxtaposed. I've always taken that word to mean "causing or evoking pity, sympathetic sadness, or sorrow." It baffles me that you can throw the book at another human being, (one who had PLENTY of reasons to wallow in self-pity, mind you, but didn't) simply for disagreeing with you, and do so under the guise of "defending yourself," all the while implying a whine that these disagreements are an "attack" on your religion. To me, THAT is the self-pity party that fits more in line with the definition of "pathetic," wouldn't you agree? Scientific discoveries are no more responsible for attacking religion, or having a motive or agenda to remove your belief in God, than learning about gravity is responsible for children eventually coming to the conclusion that reindeer can’t fly. I’m sorry, Virginia, but we lied. I don’t know if you just simply can’t grasp how it appears to the outside world, but your comment does nothing more than make you look like a petulant toddler in a tantrum because you can’t have any ice cream, and THEN taking all of the ice cream and flushing it down the toilet to make sure no one else can have any. If the weather man conveys some data that it is probably going to rain tomorrow, do you start a revolution to rise up against the hidden agenda of meteorology to wipe the concept of picnics off the face of the Earth? Of course not, that would be ridiculous, right?

Stephen Hawking was a brilliant man. He contributed so much to his field of science and had a genuine concern for the progression and well-being of humanity as a whole. I would honestly love to see your list of contributions toward bettering mankind. I have the sneaking suspicion that it would be just like mine, "pathetic." Have you actually read Hawking's work? Have you ever actually read any physics book? This is a problem in so many other areas of life and society, where someone knows “just enough to be dangerous.” You are a perfect example of this idiom in action, and your comment is perfectly indicative of someone learning what 2+2 is and then feeling they can successfully argue the elements of General or Special Relativity.

You can’t berate atheists, or any nonbeliever for that matter, for being intelligent or knowledgeable about any topic, when you refuse to educate yourself with information that is freely available to, and very easily obtained by, anyone. Hearing someone whine that “you atheist’s just think that you’re sooooo smart,” gets old, really quickly. The real irony of it is that, compared to you, that statement admittedly holds some water. But as a general rule, there is nothing that you couldn’t understand yourself if you would quite simply take the time to learn about it. Instead of pointing and laughing at these ridiculous nonbelievers running around and learning stuff, I’d suggest that you push yourself way out of your comfort zone sometime and actually give it a try. You might surprise yourself.

Look, all condescension aside, I know you have your beliefs. I know, from your perspective, Hawking is an expression of the things you feel are chipping away the the moral fabric of this world. You unknowingly got an honorary induction to my short list today, and with all of the misinformation I’ve seen lately, you just happened to be the lucky straw that broke the camel’s back, and for that, I’m sorry. I’m not going to change any of this, because I can’t lie and say I didn’t mean what I said, because I did. But, believe it or not, I do care about you and your position. And even though I’m an atheist, I very much want to live in a world where people can have faith and conviction about anything they want without having to prove it to the entire flippin' planet in order to feel justified in feeling the way they do, and more importantly, not condemn others for thinking differently. I’m not convinced that God exists, but if you are, then right on. I mean, I get it man, I used to be a Christian myself. You shouldn’t feel threatened by the world because it seems like it’s trying to take something away from you that you know full well cannot ever be taken from you. Let’s try to get this ship turned around and start acting like the amazing creatures we really are by helping each other move forward, instead of tearing each other down and holding up progress for the sake of making a point.

The man who wrote this book did his part, now let's get out there and start doing ours. We can do this.

I loved this book. Rest in peace, Stephen.

295 persone l'hanno trovato utile

AZ.

Motivational read for young adults and teenagers

Recensito in Germania il 6 agosto 2023

I enjoyed reading the book and wished I could have gotten it 25 years back.
The chapters are well explained for non-scientific audiences as well, specifically for young pupils.
Some minor content feels repetition but also appears necessary in the context of a chapter.