And on the flip side, which black holes stand out to you as particularly extreme or particularly weird?

I like to study the normal guys, and then I like to crank things up and see where things break. What’s also really fun are the oddball systems that just keep you up at night wondering: How the heck did nature let that happen? And the source that has kept me up at night is called ASASSN-18el, which is a supermassive black hole.

ASASSN-18el was found by the ASAS-SN all-sky survey as one of these black holes that were kind of normal-looking and then, all of a sudden, went into this crazy outburst. We started observing it with optical, UV, and lots of X-ray observations as well, and it just went totally bananas. It had these initial outbursts, and then it turned off — like, a four-orders-of-magnitude decrease in luminosity. And then it turned back on again and became the brightest X-ray source in the extragalactic sky for about a year, and then it began to turn off again. Now it looks like it may be turning back on.

We thought that the timescale for something to turn off by four orders of magnitude would be at least millions of years. And yet we saw it happen in a year — or in a few months. How does something like that happen?

Historically, what we knew about these accreting supermassive black holes — called active galactic nuclei — we learned from surveys where we’d look at them every once in a while. But now we have these all-sky surveys that are scanning the sky a couple of times a week, and we’re just staring at these black holes, seeing what they do. And it turns out that when we weren’t looking at them, they were doing all sorts of crazy things. Now we’re just finally realizing it.

What motivated you to get into astronomy and study black holes, and what keeps you inspired today?

The thing that really got me excited about pursuing astronomy was the discovery aspect: It was just super thrilling to be the first person to look at light that was released from around a black hole a billion years ago. That’s amazing. How is it that we puny human beings can even think about these things, or come together to build technologies to answer some of these huge fundamental questions that people have been asking since the beginning of human thinking?

And I love the community aspect of bringing people together for a common goal. We have this idea about what “science” is — that you were, like, sitting by yourself and inspired by your own creative genius, and you made all of these discoveries on your own. But that’s not what’s super inspiring about it. To me, it’s that we are able to work together and use each other’s expertise to create something so much bigger than any of us.