Black Holes

Black holes fascinate people. How do I know this? It’s one of those topics that people bring up when they find out I’m “into” astronomy. I’ve been asked about black holes in supermarket checkout lines, at book signings (back when I used to do those when I had a book to hawk), at public lectures, on planes, and online. I even had a medical professional ask me about them as I was being wheeled on a gurney into a procedure last year. Fortunately they hadn’t given me any anesthetic yet. I can just imagine what my answers to their questions would have sounded like if they had already started giving me the famous “I don’t care” cocktail!

Now, the funny thing about my perception of black holes is that I’m still amazed that they exist. Back when I was a kid and I first heard about this theoretical mathematical construct called a singularity (the high-falutin’ name for a black hole), few people thought we’d actually find any of these things. That was back a few decades ago, and in the years since then, not only have we found black holes, we’ve found them with such regularity that the American Astronomical Society has regular black hole briefings at their twice-a-year meetings. Hubble Space Telescope is getting so good at spotting the effects of black holes on surrounding matter that when a press release comes out describing the latest find, some of us joke about HST finding another “damned black hole.”

What is it about the black holes that fascinate people? Just judging by what they tell me, I’d say it’s the concept of the singularity itself. What it represents. At the very least, it’s a place where space and time act very differently from what we know out here in the non-black hole universe. A black hole is a place where gravity is so strong that light can’t escape it. And, since light carries information that could tell us what is happening inside the singularity, we’ll never be able to see “pictures” of the interior of the black hole.

Black holes are the ultimate “black boxes” of the universe; we can see the effect they have on surrounding space and matter, but we can’t exactly see the black holes themselves. They’re all over the universe, it turns out—from the stellar black holes that form when supermassive stars explode as supernovae, to the centers of galaxies, where black holes that have the mass of millions or billions of stars wallow in the galactic cores, having effects on galaxy evolution that we are only just now beginning to understand.

And, that’s the current story of black holes: not just that we’re discovering them, but that we’re finding out the roles they play in the cosmos are interesting, and possibly even necessary for the ongoing evolution of the universe.

Fascinating!