When two black holes collide, does it make a sound? It sounds like a physics class riddle, but it’s a question that haunted astrophysicist and author Janna Levin . Her new book, Black Hole Blues and Other Songs from Outer Space, tells the story of the scientists who worked on the instruments that recently detected gravitational waves, which are the ripples in spacetime caused by such collisions that can be amplified and expressed as sound.
Gravitational waves were first proposed by Einstein. Their confirmation vindicated a century of research and delighted Levin, who has studied black holes and the finite nature of the universe. (To give you an idea of how long she’s been pondering this question, her TED talk on the sound black holes might make was posted in 2011.) Her book is a profile of several brilliant scientists, an “adventure story” on the seas of high-level research, and a lyrical nod to the moody, uncertain world of a black hole, “…roll[ing] along in its own galaxy, dark and quiet until something wanders past, an interstellar dust cloud or an errant star.”
Levin will speak at Tulane’s Freeman Auditorium in the Woldenberg Art Center on Tuesday, April 5, at 6 p.m., followed by a book signing. Gambit spoke with her briefly about black holes, her book and the sound outer space makes.
So much of your work deals with these big subjects, like cosmology, that are very complex for the layperson. What’s something you find a lot of people don’t understand about black holes?
Levin: I think a common misconception people have is that black holes are dense crushes of matter...a 30 solar mass black hole, like one of the ones that collided [in the gravitational wave recording], is probably just around a couple hundred kilometers across. So you’re crushing 30 times the mass of the sun into a couple hundred kilometers. People think that means that there’s a lot of dense material there, but there’s just a shadow. Black holes are essentially nothing. There’s nothing there. And I think that gives people pause to think about.
In the book, you give this great portrait of the working lives of the individuals involved with the LIGO project. As a writer, how did you bring them to life?
Levin: It’s funny; I did not want to go near [their stories], because I’m a scientist. These are my friends. The reason why the book was two years late, and thereby perfectly timed, was because I was trying very hard not to write it. I was trying to write soemthing different.
[My editor and I] had this long talk about how anxious I was about putting myself in a funny position relative to the community by doing this, and how I’m a scientist, just like them, and I’m on the ground, just like them, and that’s why they trust me. I felt really funny about it, and he just had to kind of talk me into the risk of doing it this way, and I knew it was right. It’s just a better story. I needed someone to push me; I was hoping he would push me. I just had to sort of swallow my fear.
The recording of the "sound" these gravitational waves makes brings something that's really abstract into the realm of the physical or sensory, which we can actually experience. What has that been like for you?
Levin: That’s a really interesting question for me, because I love math and I believe in math deeply but sometimes I think I’m startled that there’s a real, physical reality that it corresponds to. I work on some very abstract things, like extraspatial dimensions and the Big Bang, and for me black holes were a conscious attempt to work on something that was real. Abstract as it might sound, and surreal as it might sound, it was a way for me to connect my abstract leaning to actual, real, natural phenomena.
I think that’s why I became so interested in the experiment [described in the book], because [with my work] I could never build something. Just that they were doing this, that they were building a machine…in a way, I have the luxury of just sort of dreaming all the time, and so for me, it was very thrilling. There aren’t really words. And also, I’m so proud of them. It’s such a beautiful experience to be excited for someone else’s accomplishments, and to be close enough to understand it and appreciate it and respect it.
This interview has been edited for clarity and condensed.