So it turns out that when you scream into the void nothing listens but if you were to step into it that's where things get interesting. People have been curious about black holes for forever and the world recently saw its curiosity reawakened a few years ago with the first picture of a black hole. Told in a way that makes you feel that you are floating (falling?) through the void of nothingness this is such an informative and calming read. So boldly go and allons-y!

Thank you to NetGalley and Knopf Doubleday Publishing Group for this advanced copy which I received in return for an honest review.

Black holes are complicated, largely because what we think we know is mostly extremely long distance observation, mixed with debatable quantum mechanics and a lot of plain old conjecture. Janna Levin, professor of Physics at Columbia, manages to explain it rationally, clearly and even excitingly in her microbook The Black Hole Survival Guide.  Spoiler alert: there is no surviving a black hole.

Levin uses everyday objects to make understanding the process and the thing easy to follow. First of all, black holes are actually nothing. It takes her some time to get readers to understand that, but black holes contain nothing and are nothing. Yet they are fearsomely massive and dense. The old cliché is that they’re so dense even light cannot escape from them. But just because we can’t see light beyond the event horizon doesn’t mean black holes are dark on the other side. All the thrashing and smashing and tearing apart could well mean it is extremely bright on the other side as energy is released. We just can’t see it from our side.  Plus, the event horizon is a hologram, not a window, she says. It contains all the information from everything that passes through, while the interior holds nothing. This kind of explanation makes the book a real page turner for me, and for sci-fi and astrophysics fans in general I would imagine.

First up for explanation is gravity. Gravitation is curved spacetime. The distortion of space means gravity fields around various bodies. Free-fall paths are curves in space, not straight lines. They trace an arc, much like throwing something across the room. Therefore the earth does not pull on the moon. Rather, it bends space and the moon falls freely along it, a very different concept. Levin says this was Einstein’s greatest finding.

A black hole, as everybody knows, is massively dense. A black hole with the same mass as our sun would be just six kilometers wide, if that puts it in perspective. It consumes everything that ventures near, and destroys it, instantly shredding it to its subatomic components. It destroys the information, the history that it carried with it for eons. Destroyed matter can reappear as flares, fairly vomited from the black hole, bearing no relation whatsoever to what came in through the event horizon. 

A black hole warps time so much it basically stands still at the event horizon. Levin uses the example of two women in a mothership far from the black hole. If one leaves and ventures towards the black hole, her voyage would seem normal to her. But the woman in the mothership would die of old age watching her. The last moment, crossing the event horizon, would appear to take forever.  From the event horizon looking out, the universe would advance billions of years in moments.
Meanwhile, back at wrapping your brain around incredible concepts, the black hole singularity that we naively think of as the center of a sphere within the black hole is really at a future point in time and not a point in space at all. She says light can no more travel toward you from the singularity than light can travel into the past. This is a further good reason why a black hole seems dark and no light escapes. It’s all in the past from our side of the event horizon.

There are contradictions to deal with as well. My favorite is that relativity’s prediction of the singularity means it cannot be.  

Levin also has the best explanations through analogy of quantum mechanics that I have seen. She says as with a musical chord vs a single note, a quantum particle cannot be in a precise place and simultaneously have a precise motion. If a particle is in a precise location, it is in a superposition of motions. If it is moving at a precise speed, it is in a superposition of locations. Position and velocity are complementary observables in physics talk. Saying particles have precise motion and location is as silly as saying a note is the same as a chord in Levin’s description.

This comes closer to explaining it in plain English than anything I have yet reviewed, which is about  ten other books on quantum mechanics now.

Bottom line: keep away from black holes. No great worry there, as the nearest one would take numerous lifetimes to reach, even at the speed of light. It’s a voyage that would end badly, unlike this fun little book.

David Wineberg

I can picture Matthew McConaughey's character in Interstellar kicking back with this book, reading about black holes and quantum entanglement for fun. And it is a fun read (if you like epic prose and cold scientific facts interwoven with beautiful artwork and a sprinkling of existential dread)! I highlighted several passages for their turn of phrase alone. How often do you read a book that uses "denizens of the astronomical galactic nucleus" and "hot mess" in the same sentence? Author Janna Levin is a master of phrase-turning, describing her own fascination with space in this gorgeous manner: "Frustrated by the fact of the heaviness of my feet on the Earth, striding at the base of sky, restless to be let in."

Although I share her first name, I do not share the author's desire to escape the bonds of solid ground. I don't even like venturing out in deep lakes or oceans where I can't see the bottom. But I found myself floating with her imagined astronauts, hovering at the edge of event horizons, wondering what could possibly lay within. She perfectly captures the mystery of black holes, simultaneously lifting the veil to describe what we do know, what is currently hotly debated, and what is most likely to be discovered in the near future. She speaks with well-earned authority about which sides of the debates she falls on, but only time will tell if the current theories about the as-yet-unknowable center of a black hole are accurate. 

This "survival guide" should be handed out to high schools and colleges across the country to help spur inquiring young minds into studying the next great wave of exploration. It was as informational as a textbook, without being intimidating or cold. Lifelong learners of any age will surely find something new in this quick but deep read! Fans of Doctor Who, Stephen Hawking, Douglas Adams, and Ender Wiggins will all feel right at home in these pages.

Do you have your passport ready?  Let’s explore the galaxy and find black holes.  I highly enjoyed this informative book that treats black holes similar to a Jet Blue destination.