Onstage at TED2011, physicist Janna Levin talked about how gravitational wave detectors are about to produce revolution in astronomy and cosmology: instead of simply seeing the universe, we’ll now be able to hear it as well, the ripples of spacetime itself. In addition to being a groundbreaking cosmologist, she’s a novelist, memoirist and artist.
We caught up with her in California to talk about supernova sounds, how the experimenters try to trick each other, and the connections between art and science.
Do you have a favorite sound you want to hear?
The black hole/black hole pairs, because they can’t be seen. They really are completely dark. It’s the only way we’d catch them. You can see other compact binaries, like white dwarf/white dwarf binaries, or neutron star/neutron star binaries, and that would be completely interesting, but we can at least see those. For those, the possibility of seeing them with light is going to be a great advantage, but it would be amazing to see something you absolutely could not see any other way.
Also supernova explosions that aren’t perfectly spherically symmetric will lead to a really nice, cool, whale-song-sounding thing.
Listen here: (courtesy of Cornish, Ott, and Burrows)
I wish I could have played more sounds in the talk. It would be great to give a better sense that this is a totally different perspective on the cosmos, that it will be totally different than any other kind of history that we have, it’s not just another telescope which is picking up just another band of light — which isn’t to imply that telescopes are trivial things, but I mean this is really kind of a paradigm shift. If this becomes extremely effective, and we start getting tons of detections, it will become commonplace, just like Hubble photos are commonplace, that we’ll have recordings of a cosmic ocean full of unexpected nuances.
What are some things we might learn from studying these signals, beyond the sheer excitement of hearing them?
There’s things that we already know we should be able to glean, and other things we can’t foresee. Obviously, it’s the latter category that’s much more exciting. But who knows, maybe there’s nothing else out there, maybe we’ll be disappointed.
In terms of things that we have a pretty good shot at detecting, we’ll be able to do straightforward astronomy, the same way everyone does astronomy with radio telescopes to the Hubble Space Telescope. The more information we gather, the more we’ll know about black hole formation, their populations, and how often they form and when they form and all that kind of stuff. So, we’ll be able to tell if black holes are rapidly spinning, if they’re slowing down, if there are magnetic fields threaded through them; if some of the very energetic events we see in the universe are caused by black holes swallowing and rupturing neutron stars. There’s a lot of straightforward astronomy that can be done once we are able to really mine the data. There’s also things like cosmology. We might be able to make distance estimates, and add to ways that we try to measure dark energy by measuring the expansion of the Universe.
With the Big Bang, it could be really interesting, because it’s possible that the earliest ringing of spacetime was just kind of washed away. The Universe expanded so quickly that a lot of that stuff got wiped out early in the Universe’s history that no remnant would be detectable today. So, we might look for things that happened later. There’s all kinds of peculiar details that could be from the early universe if we were lucky enough to be in a situation where they hadn’t been wiped out. You can imagine a universe with extra spatial dimensions, or that went through transitions from one high energy state to another high energy state, all of these things could leave some kind of record, some kind of ringing behind.
One of the exiting things about fundamental research is that you really don’t even know what the chance is of seeing some of these objects.
Well, these experiments, for example LIGO (the Laser Interferometer Gravitational Wave Observatory), would not have been build if the chances were not very good that we’d see compact binary events. In fact, if we don’t, there’s something wrong with what we understand about the universe. So, there’s always a safe bet, otherwise they don’t get built.
LIGO’s proposed space-borne counterpart, LISA, for sure will see things like white dwarf/white dwarf binaries. In fact, LISA will have a problem with having so many events that it might be really noisy out there.
There’s always a safe bet, and something you might get really lucky on. So, to not detect them would mean there’s something seriously wrong, either with how we understand the universe or with the detectors.
I was about to say that’s a very exciting thing itself, but half of that is very exciting.
Right! You know, the detectors are doing amazingly well. Recently there was something called a blind injection. The experimentalists made a detection; they heard something, they analyzed it, they came to a conclusion of what it was. But, they also knew that some of the higher-ups — a couple of the people high up in the 800-person collaboration — can trick them with what’s called a blind injection, a false signal. They want to know how well the algorithms will do with detecting it, and not tell them whether it’s a real detection or not.
Last week, it was revealed that what they were calling “big dog,” because it was in Canis Major, was not a real detection, but a blind injection.
So, the experiments are doing incredibly well at picking up what they’re expecting to pick up. They haven’t yet detected gravitational waves, but they didn’t expect to. It would have been just incredibly lucky, something going off just so perfectly that we could see it now. What we’re really hoping is that the advanced detectors in about four years will be making regular detections.
Now, when you talk about the sounds of the universe, what exactly is ringing, and what is making the sound?
So, if you’re watching a sci-fi film, and the cosmonaut gets expelled out of the space station screaming, you don’t hear his screams. There are not sound waves in empty space; this is not compression of air.
What it is, is the compression of spacetime itself; spacetime squeezing and stretching, lengths and distances changing because the space is changing.
This is a lot like the idea of banging on a drum in vacuum. The air doesn’t get compressed, but the drum is ringing out a song. So what you could do is record the waveform on a drum, and then plug that result into a stereo system, and ask that stereo to play that waveform. And it will play out a song — the song you couldn’t hear in the absence of the air.
And so, in that sense, gravity waves are very closely tied to notions of sound. They’re not compressions of air, they’re not human anatomical notions of sound, strictly, but they’re much more like sound than like pictures.
You seem to have an affinity for tragic figures in science history; you wrote a novel about Alan Turing and Kurt Goedel, and in your talk, you mentioned Karl Schwartzchild, who died as a result of fighting in World War I.
Yeah, he died within a year of writing that paper.
What draws you to these almost Greek-mythic figures?
Oh, that’s probably exactly it! Greek tragedy. It’s part of our storytelling history, that we’re drawn to the tragic hero. The person whose very qualities that make them great is also their downfall. There’s something that resonates with human beings about that.
What’s fascinating to me is how rarely scientists and science-oriented people talk about this. There is almost a fetishization …
Yeah, there is an aggrandizement, and a kind of a simplistic hero-worship. But I think the real stories are more interesting. More complex, and more evocative of our sympathy, our curiosity, and more ambiguous. I mean, ambiguity is very interesting in writing; it’s not very interesting in science.
There is a certain sense in which certain scientists — I guess the ones I wrote about — it’s almost as if they laid their lives down. We live with the repercussions of their discoveries without really ever paying any service to their accomplishments. I mean, somebody like Goedel, who is quite obscure in mainstream thinking, and yet is somehow fundamental to the way the whole world operates now, in some subtle way is behind computer science and developments in artificial intelligence, yet he kind of goes unknown. I think it’s kind of interesting to review what that intellectual history was that led us to where we are now.
You were scientist-in-residence at the Ruskin School of Drawing and Fine Art for a while.
Yeah, that was fun.
Do you find working in the arts influences the kind of science you do?
I would say the connection between art and science is very tenuous for me. It’s just that I’m interested in both. I don’t think that my interest in art affects the kind of science that I do. There is something that drives the questions that we ask that has to do with our individual disposition. There are many scientists in the world who work on incredibly different topics, and somehow our own personality quirks have driven us to these particular topics. So, there’s something that drives me about certain questions — about the origin of the universe, about the large structures of black holes — something about those questions is personal, oddly. Questions I’m drawn to I’d like to believe has some very big-picture implication, ultimately. Even if, in my scientific research, it looks extremely detailed and mathematical and like a small piece of the puzzle, one hopes that it really is pointed toward some bigger connection to what nature is and the miracle that we can understand nature at all.
In art, my tastes are completely different. I like things that are whimsical and funny, not necessarily tragic or melodramatic at all.
I do tend to find some aspects of the two personalities kind of cohesive — though some completely disparate, right? — but some completely the same: being a little outside of social norms, maybe, a little off the mainstream, not quite getting what some people think is so important about pop culture. That kind of stuff tends to be really comfortable between artists and scientists. They can look each other in the eye and have a little moment of recognition.
You referenced Battlestar Galactica in your talk; are you a science fiction fan?
I’m not. I’m a huge fan of fiction, and I love it when there’s science in the books, but not exactly science fiction.
As for the nexus of science and art in my own work, that’s where they meet, is in writing. I think there’s a certain lyricism in the telling of a scientific story. I don’t know if it came across in the talk, but there’s a certain poetic feeling about the whole experience. An event happens a billion light-years away and we’re still evolving, and it’s on its way to us, and then we’re doing cave painting and it’s right outside our door and we’re still not ready, and then there’s the natural revolution and we’re scrambling. There’s something poetic about that story.