Black holes are one of the few things that are simple enough to capture a child’s imagination and complex enough to fascinate adults, laymen and scientists alike. Having read science books like Black Holes Blues and Einstein’s Shadow, listened to science podcasts, attended panel discussions, and watched more than one video of Prof. Brian Cox explaining the event horizon, singularity, and spaghettification, I thought I knew what all science-curious laymen know about black holes.
And then I read Janna Levin’s Black Hole Survival Guide and realized I was wrong.
I knew, for instance, that black holes are basically nothing. I also knew that they are extremely massive. It never occurred to me to ask how something that is nothing can have any mass at all.
I made underlines on just about every page of this book. Here are a few quotes from Black Hole Survival Guide that blew my mind…
A black hole is a spacetime.
You can approach much closer to a black hole and remain unharmed than you can to the Sun.
Black holes just are not the catastrophic engines of destruction they’re portrayed to be… Even if you approach boldly close, within several widths of the black hole, you could set up your space station, shut off the engines, fall freely in a stable orbit that takes mere hours to complete, and enjoy the scenery for as long as supplies last.
If the Sun were replaced by a black hole tomorrow, our orbit would be unchanged.
Outside every black hole, there is a curve in space so sharp that light can fall around the hole in a circular orbit. You could jet-pack to the location of light’s circular orbit and hover there… Once there, you could shine a light on your face. Your face will reflect some of the light and send the image of your face in a reverse orbit toward the back of your head. You could wait a few tenths of a millisecond for that light to reflect off the back of your head then circle back about and land in your eyes. You could watch your own back.
Events interior to the horizon can have no effect on the outside… Happenings outside the horizon can be transmitted to the interior… The black hole is thoroughly opaque from the outside, utterly transparent from the inside.
Tiny black holes would be harmless to the fate of the world.
Traverse the event horizon of a big black hole, no problem… You could prolong your life expectancy to as much as a year in a black hole trillions of times more massive [than the Sun].
As you cross the event horizon, you will pass by the light you put there, the light that sits still even though it is moving at the speed of light…. Light gets stuck at the horizon.
Inside the event horizon what they once called time is now space and what they once called space is now time.
The black hole singularity that we naively think of as the center of a sphere is really at a future point in time and not a point in space at all.
The black hole is dark on the outside, but it can be bright on the inside.
Not only is the actual imploded substance behind the event horizon irrelevant to the structure of the black hole, it’s gone.
There are as many supermassive black holes as there are galaxies.
Pick up a copy of Janna Levin’s Black Hole Survival Guide from an independent bookstore of your choice here. It’s also beautifully illustrated by Lia Halloran.