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Talking Singularities with an Astrophysicist Sister

Talking Singularities with an Astrophysicist Sister

April 13, 2016

Rachel Perks & Emily Suvada

Mid-to-late 2015. Rachel is writing GROUND CONTROL, a play about science and women. She starts reading a lot about astrophysics, at the same time as reading I Love Dick by Chris Kraus. She quickly realises she knows nothing about science, although quite a bit about women. She comes to see that the things she wants to know about science might involve having a foundational understanding that is beyond her Bachelor of Dramatic Arts. Luckily, Rachel’s sister Emily has a degree in theoretical astrophysics.

Phone a friend. Or in this case, email a sister, subject line: “Singularities: what are they and how do they function?

Emily Suvada (Portland, Oregon) to Rachel Perks (Melbourne, Victoria)


Hey Rachel,

So singularities are a mathematical concept, really. I’m not sure if you’re asking about black holes or singularities specifically, since many people use them interchangeably, which isn’t quite correct. So I’ll just run through both to cover all bases.

To start off with – it’s probably best to go through the concept of “spacetime” a little bit. Spacetime is a mathematical model we use to describe the universe, and it’s four-dimensional which is waaaay hard to understand (dimensions: X,Y,Z, time). It’s easier to break it down into 2-D (dimensions: space (all three dimensions squished up) and time). Think of a piece of paper with a grid on it – time is an axis running vertically, space is running horizontally. Let’s define space as just distance from somewhere. So if you want to plot out a day of your life, it’s going to be a line that starts somewhere at the bottom of the page and drifts up (you are moving forward through time all day) and it’s a bit side-to-side wavy (you are moving about through space, back and forward, to the shops, etc). This is called your world line, and spacetime is the piece of paper. If you run really fast in one direction all day, your world line will be a diagonal line (going forward through space and time all day), but if you sit in one spot, your world line moves straight up (no space-travelled, but still travelling through time). That’s all pretty standard stuff – the thing where it whacks out is where mass gets involved.

So Einstein proved, with General Relativity, that mass deforms spacetime. What does that mean? It means the grid on your piece of paper doesn’t always have straight lines. Sometimes the grid gets compressed. That’s what happens around an object with a lot of mass, like a star. The problem is – because we live inside spacetime, we can’t see how it’s bent. If you go to one of those compressed or stretched parts of the grid, you get compressed too, so everything still looks normal. The compression affects both space and time. Something that’s a metre long might not measure a metre everywhere in the universe, but it’s hard to check, because if you bring your ruler there, the damn ruler shrinks too. Time also doesn’t run at the same speed throughout the universe. In fact, it runs differently in orbit than at the surface of the planet, but like I said – your clock is always going to look like it’s ticking at the same rate to you. It’s pretty mind-fucky, but it’s true. That’s just the way the universe works – GPS satellites take the time-running-differently into account or they’d be incorrect. Madness.

Anyway, what I’m trying to explain is the nature of spacetime, which is really what underpins all this stuff, but it’s the crucial thing that most people never get their head around. It’s not mass, it’s not the universe, or a thing, it’s the grid that we exist in, and it’s not uniform.

Okay – so I said that mass distorts spacetime. One amazing thing this means is that gravity can affect light, even though light has no mass for gravity to act on. Light normally travels in straight lines, but mass can bend it. As an analogy: if you roll a marble across a smooth, flat table, it should move in a straight line. However, if that table has a dip in it, or a hill, the marble will roll around it or away from it. This is what happens to light in curved spacetime. Light is running along, really happily, until it passes alongside a really big, massive object. The spacetime there is all compressed, and the light gets thrown off course. There are good videos that show examples of this online. It can actually be observed through a cool effect called “gravitational lensing”. Anyway. The greater the mass, the more the light gets bent. Once the mass gets big enough (and the spacetime gets warped enough), the light gets bent *so much* that it travels directly into the mass. Think of your marble on a table. If the hole in the table is deep enough, that marble is just going to fall in, and never come out, no matter how fast it’s going. That’s what a black hole is. The “event horizon” is the area where spacetime reaches a limit: outside it, light can get away. Inside it, light is going to fall right into the middle. That’s why they’re called “black holes”. Because no light can escape, thus they’re black, yada yada.

Anyway. What creates a black hole? A massive object that’s really, really small and dense (so it’s putting all its deformation-power into one little area). Black holes are Neutron Stars, which are unsurprisingly made of neutrons, which can bunch up really close to each other, since they have no charge and won’t push each other away. They form a ball, just twenty kilometers or so across, but they hold more mass than our entire sun (one million kilometers across). They’re so dense that a teaspoon full of neutrons would weigh millions of tons – about the same weight as a mountain. That kind of density of mass deforms space in a really big way, and the outside of the neutron star is less dense than the inside, and the very middle is what’s called a singularity. It’s something that happens when the neutrons are being pushed into one another so closely that they actually start occupying the *same space*. At the very centre of a neutron star, mathematically, there’s infinite density of mass, which means spacetime is infinitely curved. That’s what a singularity is. Everything breaks down there – logic, time, space, none of it makes any sense. One plus one doesn’t equal two. Nobody is 100% clear on what’s going on in there, even the experts like Stephen Hawking.

There is a theory, and a good one, that if our universe isn’t the only one (that piece of paper with a grid on it might be in a stack with other pieces of paper, a multiverse) then the only way you could transmit anything between them would be at a singularity. Spacetime breaks down so completely that you might just be able to get *out* of spacetime. I’m describing it in a vague way, because the thing is – all this stuff is just math. Pure, pages of math, to which words don’t really translate properly, but the fact is – it might be possible to link universes through singularities. It might also be possible to link points in our *own* universe with singularities (a wormhole). For that situation – go back to your grid on a piece of paper, and bend the paper until part of it is touching the rest. A wormhole would be a spot that’s so crazy it could link two surfaces of the paper together.

Anyway. A singularity is a mathematical construct, which is why most of the information out there is so abstruse. We live in four dimensions but only perceive three, and we experience “flat” spacetime, but in reality, it’s curved. So it’s hard. But hopefully that helps explain what’s going on there a bit. The most important thing to get your head around is spacetime. That’s the hard part, and the rest all flows from there.

Rachel’s mind is blown. She thinks about the word ‘singularity’ in its most basic definition, that being a thing that is distinct and individual. This idea feels strongly resonant with her lone astronaut, who over the course of GROUND CONTROL, stops feeling like a part of the “whole” of humanity and starts feeling very singular indeed. She does some more googling and then emails her sister again, this time asking about the technological singularity.

Emily Suvada (Portland, Oregon) to Rachel Perks (Melbourne, Victoria)


The technological singularity stuff is really cool – a lot of people associate the term with Ray Kuzweil who I love, he wrote a book about artificial intelligence (AI) called The Singularity is Near. In many people’s minds, “technological singularity” is the point at which machines start making themselves smarter, and move beyond human intelligence. Because technology tends to improve exponentially (more on that) this means that we will approach a point of nearly infinite technological progress. Hence: singularity. You can see the link with black-hole-singularities: physical measures become infinite and thus everything breaks down. That’s so non-human that I honestly doubt any humans will experience it. They’ll either bring 99% cyborg creatures along for the ride, or they’ll be hanging out at a bar, not understanding why those freaky guys in the labs are like… disappearing in flashes of light.

I need to share this quote Kurzweil made about AI’s development which scares the hell out of me in a very serious way. The thing about technology is – it usually develops according to what’s called “Moore’s law” which basically says that computing power doubles every one or two years (or eighteen months, depending on your sources). That’s exponential growth, and it’s well documented, back to the first microprocessor chips.

Anyway – when the Human Genome project was first underway, it was an immense task, and computers were really, really slow. Seven years in, they’d sequenced just ONE percent of the human genome. People were saying it was a big, expensive failure. But Kurzweil said: Oh, we’re halfway there. And he was right. He figured that if they were following exponential progress, they’d achieve another 1% in the next year, then two in the next, four in the next, then eight, 16, 32, 64… and then you’re done. It was completed seven years later, even though they did 1% of the work in the first 7 years, then 99% in the next. Based on current work in AI research, we’re probably on track to get there in another ten-or-twenty years. We’re only at a fraction of a percent along the way right now, but in exponential space that means “almost there”. But the numbers get crazy: 64 goes to 128, then 256, 512, 1024, etc. That means that three years after we achieve parity with AI, the computers could be ten times smarter than us. I don’t really know what that implies for the world, but I’m so glad I’m going to be around to see it.

Emily Suvada is a science-fiction writer living in Portland, OR. Her training in math and physics informs her writing, which focuses on what it means to be human in a world where the forces of technology and nature are increasingly intertwined.

Rachel Perks is a Melbourne based playwright and performer. She writes queer feminist texts that are mainly concerned with the search for other worlds, and other possible ways of being in this world. GROUND CONTROL premiering in Next Wave Festival 2016 will be Rachel’s second solo written work. In 2015 she co-wrote We Get It with Elbow Room.