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Gravity's Engines: How Bubble-Blowing Black Holes Rule Galaxies, Stars, and Life in the Cosmos (Anglais) Relié – 1 septembre 2012

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Book by Scharf Caleb

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Commentaires client les plus utiles sur (beta) 53 commentaires
22 internautes sur 27 ont trouvé ce commentaire utile 
Too Light Weight 9 avril 2013
Par bmbower - Publié sur
Format: Relié
However I did learn a few new things. For instance, one of the reasons astronomers observe jets of x-rays and other forms of energy shooting above and below the disk of a spiral galaxy is because the super massive black hole spinning at the center warps space into an enormous eddy. The eye of the storm, so to speak, is the only channel of escape.

But I had to wade through galaxies of fluff and silly analogies to get there. The fluff most likely arises from the maxim that you lose readers when you include equations. As a result there are none in this book. Even worse, the author strives to avoid anything that sounds too sciency. Yes we get extended descriptions about matter crashing into itself to create the energy we can see, but no scientific explanation of how that energy is actually produced and why it is not sucked in by gravity. We also learn that "[s]uper computer simulations" of baby galaxy mergers "can create enormous whirlpools of turbulence." But nothing about the simulation inputs or how they work nor the nature or extent of the turbulence.

Then there is the writing. As another reviewer says, Scharf's analogies are all over the place. Many of them are at odds with the grandiose tone he sets in the first few chapters. Galaxies are eggs. Super hot gas clouds are water in a bowl then - in the same paragraph - partially successful soufflés. Meanwhile he is inconsistent in trying to express the scale of the universe. He tells us 10 million years (or light years when referring to distance) is tiny compared to the age and size of the universe. Then he later says the time it takes to travel between two cosmological elements is greater than all recorded human history, which I guess is around 5,000 years - yet the analogy suggests he is trying to awe us with this even tinier distance.

There are other issues as well. (E.g. the histories of radio astronomy and x-ray astronomy are underdeveloped.) But the bottom line is that Scharf simply does not have the writing chops of Brian Greene or Michio Kaku or the creativity of Kip Thorne (whose spaceship-to-a-black hole conceit worked extremely well at the start of Black Holes and Time Warps). All too bad really, as I like the idea of focusing on gravity and the role of black holes in shaping the look of the universe rather than on black holes per se. This book just does not deliver on the promise.
18 internautes sur 22 ont trouvé ce commentaire utile 
Fascinating View of the Universe 18 août 2012
Par J. Groen - Publié sur
Format: Format Kindle Achat vérifié
This book is a fascinating view of the universe, including our part of it. The book focuses on "black holes" those parts of the universe that are the most dense and the most energy productive. Every galaxy, including the Milky Way, our galaxy, has a black hole in the middle of it. Around the black hole, there exists the most concentrated grouping of stars which in many instances are "buzzing around the black hole" at tremendous speeds and then circle around the black hole until they are swallowed by it, much like a drain does with water. When this happens, an explosion occurs and energy is released in the form of radioactive gas, protons and neutrons that spews out thousands of light years into the universe.

These are called black holes because they appear that way in the universe because they are so dense that no light escapes from them. They are billions of times more dense and powerful than our sun. Since there at least 100 billion galaxies in the universe with at least 100 billion stars in each (think about those numbers, they are mind boggling), there are least that number of black holes. These black holes perform a key role in the universe creating and re-creating the universe through the creation and destruction of stars and galaxies.

Most of the book is spent discussing the exploration of these monsters, both nearby (our galaxy and others within millions of light years from us) to billions of light years away. The author mentions one galaxy and black hole that he was involved in the discovery of that is 12 billion light years away from us. (The interesting thing is that they found this galaxy and black hole as it looked 12 billion years ago...) A picture is shown of these and other galaxies with their black holes in their middle.

It just happens that our galaxy and black hole are just right for life. The black hole in the middle of the Milky Way galaxy is hungry, destroying and creating a couple of stars each year, but not too destructive. This results in positive change in our galaxy that supports life on its fringes where our Sun and earth exist. The author goes into some detail on this explaining how important this is to life on earth.

At the end, the author actually gets somewhat poetic, and the prose is very uplifting and positive. The universe is a beautiful creation and these monsters, black holes, are key to the creation and continuation of this beauty. The pictures in the book just increase the value of the writing and thoughts provided. In fact, I like this book so much, that after purchasing the Kindle version, I plan on buying the hard copy (only the 2nd time this year that I have done that), so that I can offer this to others to read. I highly recommend this book for anyone interested in the universe and astronomy.
7 internautes sur 9 ont trouvé ce commentaire utile 
I couldn't get past the writer's awkward style and excessive use of analogies 14 février 2013
Par Just Ducky - Publié sur
Format: Format Kindle Achat vérifié
There is some very interesting information on black holes in this book. Some very technical descriptions that will require more of a background in astrophysics. But the author's writing style reads likes aDiscovery channel narrative that relies on simple analogies that are more distracting than helpful. "ThIs is the beginning of the galactic axial hub. Like the distorted yolk of a Hugh fried egg.... I kept thinking I was reading an old Philip Marlowe detective novel from the '40’s.

Anyway, the author's writing style makes the book a more difficult read than the technical information in the book.
4 internautes sur 5 ont trouvé ce commentaire utile 
Fine book about Black Holes, for what it is. 29 août 2013
Par emmerwood - Publié sur
I'm a subscriber to Scientific American and have seen this book advertised there for the past few months, so since wanted to learn more about black holes, I decided to give it a try.

I found this book to be a good basic overall review of what black holes are and the part they have played and continue to play in our cosmological evolution, but now that I have finished the book, I find that did not get out of it as much as I had hoped to. True, I can explain to my co-workers what a black hole is, how they formed and where they likely are (if this topic ever comes up in our conversation), but not much else. I know that the book covers more about black holes, but none of it stuck, so I am at the point of not knowing which to blame for that, the book or myself. After I finished it, I still had to re-read the section on bubble-blowing to remember what the author wrote.

I'm a bit uneasy at the author's writing style and the overuse of colloquial references to what he was trying to get across. I felt that I was being slapped on the back and expected to smile at some of these comparisons, and that detracted from the subject material in my opinion. I know that this is not a text book, nor did I expect it to be one, but I would have rather seen a bit more Brian Greene and a little less David Sedaris.

Would I recommend this book to a friend? To my neighbor who is a retired factory manager, my neighbor who is a high school physics teacher, no. If you are reading this review to see if you should read it, well if you know little more about a black hole than its color, then yes, you should give it a try. Anything beyond that, I'd look elsewhere.
1 internautes sur 1 ont trouvé ce commentaire utile 
Black Stars 11 février 2013
Par Susman - Publié sur
Format: Relié
When I was young boy Black Holes featured more in science fiction than science fact, while theory said that they existed in the Cosmos - science had yet deliver a factual premise for their existence. First visual proof of existence of black-holes came in 2012!

This book grabs you from the get go, as the author takes us on an unbelievable journey, that makes our human life span pale into insignificance, as distant star light takes billions of years to reach Earth's Observatories. The author gives us time line of black hole physics and the research that went into better understanding them.

We also hear of supermassive black holes as the largest type of black hole in a galaxy, which are on the order of hundreds of thousands to billions of solar masses. Their role in the evolution of Galaxies is thought to be `key' to the star formation process. To some up then this book is both well written and relatively easy to understand. The glossary at the end is well stocked with additional information and the potential for the reader to take up further research. This book is highly recommended.
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