A Brief History of Time

Non ho le basi.
Sul serio, non ho le basi per commentare questo libro. Per questo, con lo stile pacato che mi contraddistingue la butterò in caciara come al solito.

Premessa:Stephen Hawking ha pubblicato questo libro nel 1988 e, se la legge della scienza è giusta, quelle che ho letto potrebbero essere teorie superate. O quasi.

È una breve storia del tempo e di tutte le teorie ad esso collegate.
Questa cosa dello spazio-tempo che si curva e fa cose, non è proprio intuitiva ma io penso quadrimensionalmente già dal 1985 quindi, almeno per le prime 4 dimensioni, ero preparata.

Essendo un testo di divulgazione, grazie a Dio, è privo di formule ed equazioni, eccetto quella famosa di Einstein che tutti conoscono almeno di nome.
Ma è anche il suo limite perché niente può essere spiegato davvero.

Il problema della fisica teorica, pare, sia questo: Einstein (e tutte le leggi che regolano le cose enormi che girano per l' universo) nn va d'accordo con la fisica quantistica (e tutte le cose molto piccole che girano per l'universo), quindi l'ideale sarebbe trovare una teoria unificata che risolva il tutto. Per ora, dice Stephen, si razzola nel buio e si creano soluzioni con incomprensibili(per me) virtuosismi matematici che mi ricordano tanto quando in un compito in classe facevo operazioni a caso e senza apparente giustificazione logica a parte far venire fuori il risultato che volevo.
Un 4+ assicurato con menzione d'onore per "la scaltrezza e l' inventiva dimostrata nel raggiungimento dell'obiettivo". Ora finalmente capisco il senso di quella nota. Un 2 sarebbe stato scientificamente irrispettoso, grazie prof!

Una parte che ho adorato è quella sui buchi neri, luoghi spaventosi e affascinanti. Sublime è il momento in cui SH fa body shaming alle stelle che diventano buchi neri perché troppo grasse. Lo dice davvero(più o meno) e per questo l'ho amato.

Ora.
La prima regola dei buchi neri è che chi cade in un un buco nero, rimane nel buco nero. E nel mentre muore male.

Sembra però che alcuni emettano delle radiazioni che noi per comodità chiameremo "rutti di apprezzamento digestivo" . Ma ciò non è possibile perché infrangerebbe la prima regola di cui sopra.

Ma non è il buco nero a ruttare, dice, ma sono solo alcune particelle che si trovano proprio lì vicino al punto di nn ritorno e riescono a sfuggirgli.

E poi si lancia in questa entusiasmante spiegazione che io riassumeró così :
Una particella è come un cavaliere dello Zodiaco. Per ogni Pegasus Bianco esiste un AntiPegasus Nero che girano per le galassie uniti come gemelli siamesi.
Pegasus nero è quello sfigato destinato a morire ma chi lo sa, magari no.
Cmq quando la particella siamese Pegagus si avvicina con arroganza a un buco nero, può succedere che Pegasus Bianco ci cada dentro MA se Pegasus Nero è più furbo e più forte può riuscire a separarsi e scappare. E quella è la radiazione che noi scambiamo per rutto.

E poi ho crashato.
Connessioni neurali in down per sollecitazione eccessiva.

Parlando seriamente, si vede lo sforzo di spiegare cose complicatissime, lo apprezzo, può essere un inizio e poi appassionarsi e approfondire. Non per me, ci vorrebbero almeno 20 anni di lacune da colmare.

Di sicuro quello che ho apprezzato è l'umorismo. Davvero. Era un simpaticone e avrei tanto voluto una sua biografia su Newton, dipinto alla fine del libro come una persona davvero a modino.

La cosa bella che mi ha consolato è stata la parte in cui dice che sì, è roba complicata, ci vuole tempo e dedizione per capire queste teorie e gli stessi scienziati che se ne occupano per ora non riescono a comprenderne che una minima parte dopo anni di studio.

La scienza è un processo in in divenire, va sempre avanti anche se ogni tanto imbocca la strada sbagliata. Fa parte del gioco.

Per questo mi aspetto che un giorno un tizio se ne uscirà con "erano tutte csxxate, i conti erano sbagliati!" E cambierà di nuovo tutto. Che poi è quello che ha fatto Galilei, che poi ha fatto Newton che poi ha fatto Einstein...perché oggi dovrebbe essere diverso?

Ένα πολύ ωραίο βιβλίο εκλαϊκευμένης επιστήμης που εξηγεί βασικές έννοιες της Φυσικής και πώς αυτές διαμορφώθηκαν ανα τους αιώνες - με κύρια κατεύθυνση στην μοντέρνα Φυσική που για πολλούς είναι ακατανόητη. Μου άρεσε πολύ ο τρόπος γραφής και το χιούμορ του Χώκινγκ αλλά θεωρώ πως κάποιος πρέπει να έχει κάποιες σχετικά γερές βάσεις Φυσικής για να το κατανοήσει. Θέλω πολύ να ξαναδιαβάσω τα κεφάλαια για την θεωρία των χορδών και τις μαύρες τρύπες γιατί νομίζω πως πολλά πράγματα τα έχασα. :(

I guess no one in their right mind would dare to challenge an assumption that Stephen Hawking is the greatest mind of our era and probably one of the top-10 all-time greatest. Does that mean he knows what he talks about and what he constantly argues and proves in this book? You bet your ass he does. Does that also mean that this is a good book? Surprise, but the answer is a no.

Now please don't crucify me for blasphemy just yet and listen why this book was below expectations for me. I've read/watched most of the science popularization frontrunners besides Hawking - or, alternatively, we might even call them sci-pop influencers - Carl Sagan, Neil DeGrasse Tyson, Brian Cox, Michio Kaku and they all are better than Hawking in providing fun besides plain facts. Would a random 14 year old kid be impressed enough to consider studying to become a scientist after reading Kaku? Likely. Tyson or Sagan? Maybe. Hawking? Sorry, but no. I guess the most significant reason for this is that Hawking, being the smartest man in the world, overrated the intellectual capacity of those pretty much average joes that would read his book and went for complicated instead of simplified. Simply put, if you want to read this book properly, you need to know a lot and know it beforehand, because in this book you won't get everything chopped, served and even chewed for you.

I can't say that I'm the ultimate smartypants, but I've read an article or two, or a book or two on themes Hawking examines in "A Brief History of Time", like black holes, arrow of time, the Big Bang, etc., so I should have been prepared and ready. Alas, I have to admit, that there were more than a few moments that I have realized I could have been reading it in Swahili with the same rate of success.

Despite I've said that it's not a good book, it's not really true. It is a really good book, but only conditionally. It might, and probably will, blow your mind. I cannot do anything but admire Hawking and his singular mind. But the complexity and lack of fun makes this book a read well-suited only for the hardcore fans. A very strong 3*.

I felt so DUMB reading the technical passages

Wow, what a book. So comprehensive, yet written in laymens terms and cranking up the technical information with each chapter, so you don't feel completely lost. By the time you reach quantum mechanics and string theory you almost feel like you know what's happening. Okay, so you still have no idea how any of it works, but that's alright.

I've never felt compelled to read this. A book about space and physics is not my go to reading material and all of it sounds way over my head. However, it's such a well known science classic that I think a lot of people still have it on their tbr list. One for later.

I wish I'd read this before and hadn't been so afraid of the science. It was easily digestible, broken into smallish chapters and often recapped previous topics, to help them really sink in. I still don't understand how black holes work, or how the universe was made, but neither does anyone for sure. I'm glad that others do the hard work to try to find out though.

It is not clear to me who is in the target audience for this book. At times it tries to explain basic concepts of modern physics in simple language, and at other times it assumes a familiarity with the same subject. For the first time I think I "understand" why absolute time is not consistent with relativity theory or that space-time curvature supplants the notion of gravity, and for that I thank the author. There are a few other things I believe I have a glimpse of having (finally) slogged through the book.
On the other hand, there are many places where he writes as if it were clear what he is talking about even though it would require a good deal of background knowledge. To give but one example, he starts talking about summing up over possible world histories (I cannot locate the quotation) without explaining what that would mean. Trained in statistics, I have some idea that he is talking about mathematical expectation in the context of quantum mechanics, but I don't know how another reader might make any sense of it (and I certainly don't have more than a vague notion).
There are irritating writing practices that could have used some editing, e.g., the use of the naked pronominal adjective "this" when in the middle of a dense explanation of an abstruse concept(e.g., "This had serious implications for the ultimate fate of massive stars.").
My biggest complaints, however, are about his philosophical opinions. Obviously he is entitled to think as he wishes about the ultimate questions, but his assertion that his hypothesis of a finite world without beginning or end would leave no place for God seems beside the point. The classic divide has not changed: some folks look around and say stuff just is, and other folks say there's a power behind the stuff that has at least as much going for it as we do. That argument hasn't changed with his theories. At one point in the book he claims that the late John Paul II told gathered scientists that they mustn't inquire into the Big Bang because that was God's territory. I would wager with anyone reading this comment that such an assertion is just plain false. JPII was a flawed mortal, to be sure, but he was no dope; it certainly sounds to me like someone hearing what he thinks the pope would say. (And the Galileo jokes are pretty dumb -- does anyone think that JPII, who apologized for the embarrassing Galileo fiasco, would go after this guy? It must be all that influence the Vatican has had in Britain over the last 400 years that has him scared.)
Other philosophical complaints involve his use of entropy (he defines it first within closed systems and then uses it to explain why the "thermodynamic arrow of time" and the "personal arrow of time" must run in the same direction -- leaping from a box of molecules to the entire universe!), his droning on about what black holes are like when he doesn't know for sure they exist, his statements about "random" and being 95% certain a theory is true (does that mean about 95 out of 100 theories like that are true??). His opinions may be very rich, deep, though-provoking, but how would I (or most general readers) know? You can't really evaluate a judgment unless you know something in the field.
And so that is why I ultimately cannot recommend this book: if you know physics inside and out, you might find his opinions interesting. If you don't, you can only walk around parroting what he says about black holes as if you had a clue what you were talking about. What we all really need is a remedial course in physics!

n  What is it that breathes fire into the equations and makes a universe for them to describe?n

The thing about reading something by Stephen Hawking is that by the time you're finished with the book, you're hooked. Few scientists manage to inspire their passion for their field in their readers as he does, in fact it was thanks to Stephen Hawking that I almost pursued a career in physics (but that's another story).

A Brief History of time is, in a way, the precursor to all Hawking's other books written for the general public, which include The Universe in a Nutshell and, my personal favourite The Grand Design. In one manner, it's "gentler" than his other books, in the sense that he takes your hand as a reader and calmly guides you through the physics, all the while avoiding confusing you with the gritty maths (which would have made his job considerably easier). Yet that doesn't dull the book down for the "experienced" reader who has some experience in the subject, in fact what is more ambiguous in other book becomes clear here.

A Brief History of Time is the perfect title for this book. Because Stephen Hawking is not just rambling on about the universe; he is telling a story. In fact he's telling THE Story: the tale of the universe where every other tale imaginable dwells.
Stephen Hawking explains the complicated in a simple way, elevating the reader to his intelligence. He also offers a fair deal of background information on the scientists he mentions, making them individuals and not just names that come before a theorem. And if you read attentively enough you get a precious glance at his wonderful wit.

Why is this such a good book? Because by the time you reach the conclusion, you'd be asking for more.

I've owned this book for some time, and with Hawking's death last month, it seemed appropriate to finally crack it open to see if I could understand any of it.

I was pleasantly surprised to find I was able to digest maybe 75 percent of it, which is pretty good for me and astrophysics. Hawking does an excellent job of breaking down some of universe's hardest concepts to grasp, and if I still couldn't wrap my mind around the notion of imaginary time and remembering the future, it's not his fault.

I'm sure there are more updated versions of the story Hawking tells – the history of the cornerstone theories of gravity and relativity and the discovery of black holes and rise of quantum mechanics – but this is clearly a foundational text, a standard those other books must attempt to meet. I feel I now appreciate much better not only Hawking's impact as a scientist but his impact as a writer and ambassador of science. Well worth reading.