Trous blancs / White Holes (Carlo Rovelli)

to study something is to enter into a relation with that thing, to form correlations that allow us to represent, simplify and predict how that thing, that process, will unfold.

to understand is to identify with the thing understood, to construct a parallel between something in the structure of our synapses and the structure of the object in which we are interested. knowledge is a correlation between two parts of nature. understanding is a more abstract but also a more intimate commonality between our minds and phenomena.

this interweaving of correlations — between the endless richness of our individual and collective memory, and the fabulous richness of the structure of reality — is itself an indirect product of the equilibration of things in time.

8 thoughts on “Trous blancs / White Holes (Carlo Rovelli)

  1. shinichi Post author

    perhaps this is the reason why we are interested in what happens at the end of a fall into a black hole… come to think of it, it is also perhaps the real reason that i write. or better: why i write and rewrite these pages, composed in layers and continually shuffled and re-shuffled… the order of the words has little to do with the jumbled order in which they were born (what i am writing now is the fifth revision). the order of time has always something of a reconstruction about it. the flow of reality is always more fluid than any of our frantic attempts to capture it might lead us to believe, time is not the map of reality: it is a kind of memory storage device…

    to study something is to enter into a relation with that thing, to form correlations that allow us to repre sent, simplify and predict how that thing, that process, will unfold.

    to understand is to identify with the thing under stood, to construct a parallel between something in the structure of our synapses and the structure of the object in which we are interested. knowledge is a cor relation between two parts of nature. understanding is a more abstract but also a more intimate common- ality between our minds and phenomena.

    this interweaving of correlations between the endless richness of our individual and collective memory, and the fabulous richness of the structure of reality – is itself an indirect product of the equili bration of things in time.

    we creatures of thought and of emotion are this interweaving that is formed at the macroscopic level between ourselves and the world, we are not just social beings who live on relationships with other human beings, and biochemical organisms that burn free energy from the sun, in common with the rest of the biosphere, we are also animals endowed with neu- rons that are interwoven, thanks to these correlations, with other parts of reality.

  2. shinichi Post author

    Unlike a speck of dust, it does not have electrical features, and therefore does not interact with light. It cannot be seen. It only has its extremely weak gravitational force.

  3. shinichi Post author

    White Holes: Inside the Horizon review – Carlo Rovelli turns time on its head

    by Kevin Fong

    In his latest brief but dazzling journey to the edges of understanding, the theoretical physicist takes us into the heart of a black hole and out the other side


    I read Stephen Hawking’s A Brief History of Time more than 30 years ago. It woke me up to the wonders of the universe in a way that nothing before ever had. And while I’m not sure I fully understood it then, or now, it certainly felt like an adventure. Carlo Rovelli’s new book is a kind of non-linear sequel in which he introduces his theory of “white holes”, how they might form and why we have such trouble seeing them in the universe today.

    Black holes form from stars so massive that when they reach the end of their lives and all their fuel is spent, they collapse to form bizarre objects from which nothing can escape, not even light itself. Albert Einstein’s theory of general relativity predicted their existence: entities within which space and time had to come to an end.

    But the same equations of physics that predicted the existence of black holes also predict the existence of their inverse: white holes, objects that you cannot fall into, from which matter can only pour. Astronomers can see black holes, or at least evidence of them as they hoover up matter in distant galaxies. But, curiously, we don’t see any evidence of white holes, which is a little strange and has led some to suggest that they might not exist.

    But Rovelli is a firm believer. His new book outlines his theory of white hole formation. In it he takes you on a guided tour, first leading you into a black hole, beyond its event horizon and into its throat. And there, with you expecting to reach a cosmic cul-de-sac, he departs from the expected narrative and shows you something new. This is a black hole. Things should finish here; space and time themselves should end here. But in Rovelli’s version of the universe, they don’t.

    Rovelli is an accomplished theoretical physicist, prolific author and lyrical science communicator. White Holes is a small book – Rovelli’s briefest yet – and smashes through a lot of material at breakneck speed, pretty much the entire content of A Brief History of Time in a couple of short chapters by way of overview and introduction. Reading it is more akin to the final psychedelic sequence in the movie 2001: A Space Odyssey: you’re not sure where you’re heading but it feels bloody exciting.

    In fewer pages than it would take some authors to describe how they would prepare an omelette, Rovelli drags you into the heart of a black hole and then – somehow – out the other side. What he suggests is that, as the star forming a black hole continues to collapse, it eventually becomes so compact and tiny that the laws of general relativity have to give way to the laws of quantum mechanics.

    Quantum theory is the physics of uncertainty on a tiny scale. Here, particles and patches of space become clouds of probability and the previously impossible becomes possible. All of which Rovelli exploits to suggest that the star at the centre of a black hole, trying to collapse away to nothing, might reach a point at which quantum uncertainty allows it to “bounce” backward through time and become a white hole.

    Books about extreme cosmic objects are hard to write well – and harder still to precis – partly because these theories are best expressed in mathematical terms. Indeed, they can only be fully explained by using mathematics. So no matter how dense or vast the text of a popular science book, without the requisite arcane symbols and algebraic notation you’re never going to be able to get the whole picture.

    But this is a book for the layperson and Rovelli understands this limitation, glossing over finer detail in pursuit of an impression of the wonder that lies at the heart of the cosmos and his theorising. And in his hands it’s an effective technique.

    Rovelli leaves you upside down. Having started with a black hole, an object into which you could only fall, from which there was never any escape, he conjures a white hole, from which things can only pour. He turns time on its head, runs it backwards and finally helps you understand how white holes might plausibly form and at the same time why – despite their existence – astronomers don’t see them spewing their matter into the universe like Regan in The Exorcist.

    Despite the book’s brevity, Rovelli doesn’t flinch from discussing the tougher concepts. He warns you that you might find some of them a little confusing. I must confess that I’m still a little hazy on whether or not my inability to remember the future is just a perceptual illusion, or if it’s a fundamental consequence of the underlying physics. But Rovelli reassures you that none of that really matters and that what’s important here is the experience of being transported. If that’s true then the book more than does its job.

    One of the things I most loved about White Holes was the glimpse Rovelli gives you into the mind of a physicist working at the edges of the known universe, and the fundamental insecurity of creating groundbreaking theories and then putting them out there like clay pigeons launched from a trap. It’s a strange duality. On the one hand, you have to be rock solid sure of the ideas you propose. But on the way to assembling them – and afterwards – you have to have the discipline to doubt them and continue to test them as fiercely as your staunchest rivals might.

    Rovelli also openly worries about the book and its structure, telling us that his harshest critics are physics students, who tend to get cross about the lack of detailed exposition. And if you’re a final year undergraduate looking for revision notes to accompany your module in high energy astrophysics, this volume may disappoint. But if you want to remember why you once fell in love with the idea of the cosmos, or want to fall in love with that idea for the first time, then this book is for you. For my part, I found myself following Rovelli into a weird and wonderful new universe and I was very content to be there.

  4. shinichi Post author



    『White Holes』
    Carlo Rovelli 著、Penguin Books、2023年刊

    尾関章さんが「めぐりあう書物たち」で5回も取り上げた物理学者のカルロ・ロヴェッリ。今週は、そのロヴェッリの最新本を読む。『White Holes』(Carlo Rovelli 著、Penguin Books、2023年刊)だ。これを読むのは、好むと好まざるとにかかわらず、金曜日の書評の「本家」である尾関さんへの挑戦になってしまう。




    さあ、ウォーミングアップが済んだところで、カルロ・ロヴェッリの『White Holes』に身を委ね、ブラックホールの奥のほうへの意識の旅に出てみよう。バーチャルリアリティーを楽しむ時に装着するヘッドセットのようなものを装着する。意識は遠い宇宙を漂い、ブラックホールに導かれてゆく。














    ロヴェッリの『White Holes』は、そんなホワイトホールのことを、専門家でなくてもわかるように説明してくれる。ブラックホールで終わるはずの空間と時間を、その先まで見せてくれる。


    何かを知るということは、その物・そのプロセスを表現し、単純化し、予測することを可能にする相関関係を結ぶこと。何かを理解するということは、それと同一化することであり、その構造と私たちのシナプス構造との間の類似点を構築していくこと。この辺のことは、英訳の『White Holes』を読んでもわかりにくく、仏訳の『Trous blancs』を読んではじめてストンとくる。ロヴェッリの文章は、もしかしたら、翻訳が難しいのかもしれない。いずれにしても、理論物理学者は、そんなことまで考えているのだ。












    物理学科に籍を置きながらちゃんと物理を学ぼうとしなかった私がロヴェッリの『White Holes』を読んでいたら、人生は変わったのだろうか。いや、変わっていなかったろう。年老いて読んだからこそ、楽しかったのだ。年を取って生きているのは、なんといいことか。そんなことを考えさせられる一冊であった。

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