Black Holes Don’t Suck, They Blow

A CONVERSATION WITH ASTROPHYSICIST ROB THACKER

Jasper Fitzhugh, October 16th, 2014

Submitted by Rob Thacker

Submitted by Rob Thacker

Ever wonder if people who study space have the same reaction as you do when they see a shooting star? Is it an exciting and potentially perspective-giving event, or simply a meteoroid burning up as it passes through the atmosphere? What is it like spending every day grappling with the physics of the universe, and does it change the way one sees life here on Earth?

Rob Thacker is an astrophysicist with the perspective of both a stargazer, and a scientist who spends his time neck-deep in the complex and theoretical mathematics required to truly understand how our universe works. He is a professor and Canada Research Chair in astrophysics at Saint Mary’s University, and spent 40 minutes with me discussing everything from our changing relationship with space, to massive black holes.

NW: Does a shooting star still move you?

RT: How can you not be moved by that? I mean this is a tiny, less than a pebble-sized object in many cases, going tens of thousands of miles an hour!

NW: Really? That’s a pretty small object to make such a big impact. On the subject of impact, what do you think draws people to astronomy?

RT: I used to think everyone was drawn to astronomy, but I’ve grown up enough to know that is not the case. I think astronomy draws a certain kind of person—a person who wants to know how they fit in. In many ways, the night sky is the ultimate ego-crusher. It makes you feel incredibly small when you understand how huge the universe is. But it also makes you realize how incredible the Earth is. If our Earth is like this, imagine the possibilities. It’s unbelievable to think about. There are probably billions of planets in our galaxy, and hundreds of billions of galaxies—the numbers are just silly.

NW: When you say less people are drawn to astronomy, do you mean as an academic discipline, or in terms of people’s general interest in the stars?

RT: I’m a little bit sad to say that I think it’s both. We’re certainly finding there are fewer and fewer students that want to study astronomy now. I genuinely feel huge amounts of sympathy for undergraduate students. Never has a degree cost more, and been worth less, and so many people have degrees now, it doesn’t really differentiate you from someone else. So we’re seeing students who aren’t looking at their degrees for education, looking at them for vocation. So keeping astronomy going in that environment is a challenge, because students ask: “What’s the point in studying that? What kind of job am I going to get at the end of it?” The ironic thing is that astronomy frequently comes out near or at the top for the percentage of graduates employed when compared to other fields. It’s not really because there are lots of jobs in astronomy but rather the students get lots of transferrable skills. But it’s very hard to convince high school graduates of this.

NW: What about the general public?

RT: My honest viewpoint is that interest is waning. If you go back 50 years ago, there were often front-page news stories about things in the sky. Back then, something in the night sky could really get people talking. Now, with so much light pollution, there aren’t that many places you can go and see what a really dark sky looks like. When you have two thirds of the world’s population in cities, that’s almost four billion people who don’t really know what the night sky looks like.

NW: Can you speculate about what our loss of connection to the stars will cost us as a society?

RT: I have a pretty simple view on that. We tell ourselves that humanity has done incredible things, but we live on a pretty precarious knife-edge. Once we start fooling ourselves into believing that we understand everything worth knowing, and don’t have an appreciation for the wonder and the amazing number of things we don’t know, I think that creates a completely false sense of superiority. One of the things that has been common through the history of mankind is looking at the stars, and having them put us in our place.

NW: In one of your articles for Alternatives Magazine you said that space is a “cultural compass.” Is that your way of saying space makes us ask some big questions about ourselves and our existence?

RT: It puts into context both how unspecial we are, but also how special what we have is. The Earth could be unique—we’re just starting to understand details about other planetary systems. We now have details on over a thousand planetary systems. But the more we look at those, the more it looks like our solar system is unusual. A lot of the orbits in the solar system, for example, are not similar to what we see elsewhere. We still need to do a lot more research on this, but it’s just possible we live in a very unique planetary system. I love that about astronomy—that it simultaneously makes you realize that you’re both insignificant and yet special. I can’t think of many other things that do that.

NW: Clearly, you grapple with the size of the universe all the time. How smart do you have to be to be an astrophysicist?

RT: It’s not black and white. You need to have a certain amount of brain power if you want to do this professionally. But I honestly believe that sheer curiosity is the most important asset. There will be days when you wake up and think nothing is working, and you just want to quit. You’ve got to have something to push you through that. Also, the very best people in the field work unbelievable hours because they love it so much.

NW: This stuff bends my brain. I’m not sure I could do it for a living.

RT: A lot of people get hard on themselves because they can’t think of a common sense way to understand these concepts. The reality is our common sense is a very limited thing. So when people ask about my understanding of the universe, I explain that I understand the math, and I understand the numbers. But common sense-wise, I have no framework for that. Interestingly, once you tell people that you don’t have a common sense way for understanding these things, you can throw really crazy things at them, and they’ll accept them.

NW: Like what?

RT: One of the things that really bugs people is: what’s outside the universe? They understand that they live on a certain street, and that street is in a certain town, and that town is in a certain country, and that country is on the Earth and so on. We’re used to the concept of “embedding.” But when you talk about the universe, you can’t really talk about what’s outside of it, because it doesn’t make sense. The universe IS everything, and if it’s everything, you can’t have something outside of it. Then people say ‘I don’t get that,” but that’s only because they’re used to the idea that something has to be inside something else. But mathematically, it doesn’t have to be.

NW: Is that why the concept of a multiverse is so popular?

RT: In all honestly, that’s a confusing term because it means different things in different contexts. I’m actually a subscriber to the Many-world’s interpretation of quantum mechanics, and the multiverse idea comes up in that theory. [Authors Note: Many-worlds implies that all possible alternative histories and futures are real, each representing an actual “world” (or “universe”).] But people also talk about multiverses in terms of “inflation,” and bits of space-time are pinched off from other bits of space-time, and all these different universes make up the multiverse. That’s different. I’ve always thought that people like this theory because it just sounds cool. We always tend to build bigger theoretical frameworks as well.

NW: That reminds me of a Star Trek: The Next Generation Episode where a time-space fissure results in a whole bunch of possible Enterprises appearing in the same area of space.

RT: Yes! It would be really cool to grow up in a world where quantum mechanics happened to everyday objects so we intuitively understood it. But of course we don’t. Things bounce off walls. They don’t suddenly go through. So people think, “Oh you’re just pulling my leg” when you talk about quantum systems passing through barriers, but theoretically, that’s what happens.

NW: Well, since you’re blowing my mind, what are you studying right now?

RT: What I’ve been working on recently are super massive black holes. These are black holes that are a million times more massive than the sun. They sit in the middle of galaxies, and basically material is falling into them all the time, so they are growing and growing. But you know how when you rub your hands on your jeans really quickly and they get really hot? That’s friction. What happens with these super massive black holes is that they get surrounded by ridiculous amounts of material, and the atoms rub together and get really hot—hundreds of millions of Kelvin hot—and that releases radiation which often actually pushes material out in the galaxy out of the galaxy. In other words, black holes don’t suck, they blow! And we think these massive black holes prevent galaxies from getting really, really big.

NW: I guess that makes sense, if there are billions of galaxies in the universe?

RT: Right! We’ve only really come to truly appreciate the impact of these black holes in the last decade. But perhaps even more amazingly we’ve figured this all out from the backyard of a not particularly important star in a not particularly important galaxy. And as we get to look further out, and to look at everything around us in yet more detail, I can’t stop myself from being incredibly excited about what we’re going to find. One of my colleagues suggests we’ve discovered more about the universe in the last 20 years than we did in the previous two thousand. If that’s the case, our greatest discoveries are still to come!