The end of the universe? ‘It’s a fun thing to think about astrophysically speaking’

Cosmologist: Katie Mack is a theoretical astrophysicist at North Carolina State University

“It’s just a fun thing to think about as a physicist. I really enjoy it.”

Interviewing someone who finds real pleasure in their work is always an enriching experience, and Katie Mack certainly does seem to love what she does.

A theoretical astrophysicist – a cosmologist, to be precise; someone who works within the field of astrophysics which studies the physical origins and evolution of the universe – Mack is an assistant professor of physics at North Carolina State University.

She has written a popular book to make some of the most fascinating aspects of what she does accessible to a general audience and during lockdown, I call her at home in Canada via Skype. The “fun thing to think about” that she mentioned? That would be the end of the universe.

I’m quite disturbed by the thought of death, and of everything that has meaning to human beings just ceasing to exist. But it has given me a better sense of the transience of my own life, and that you have to find ways for things to matter as they happen

“There are a lot of books about the beginning of the universe, but the ending? That’s a part of the story that people find so intriguing, so scary. It really comes down to wanting to know ‘What’s going to happen to us? Where is the meaning if we live in a universe that’s ultimately going to be destroyed?’”

So Mack is interested in the coming apocalypse. It’s not a question of if, she says, so much as when. She wrote The End of Everything (Astrophysically Speaking) to explore five theories of how the whole thing might go bottom up (not literally – astrophysics is complicated but I don’t think that’s one of the potential outcomes she describes).

They all have names that sound like coroners’ shorthand for various types of ironic, accidental deaths while attempting extreme sports on a sun holiday – there’s Big Crunch, Heat Death, Big Rip, Vacuum Decay and Bounce. Each one is an intriguing narrative about what the end might look like.

These theories are enjoyable to read about; Mack’s pop culture references (there’s even a Hozier quote in the book - and the singer name checks her in his 2019 song No Plan) and buoyant, jocund tone – she calls it “cheerful nihilism” - ensure the book is far from grim or disheartening.

The thing that most of us struggle with in relation to all of these theories, according to Mack and the panicked emails she says she gets from people around the world who are horrified by the prospect of the universe just ceasing to exist, is our own irrelevance in the story.

Katie Mack. Photograph: Nerissa Escanlar
Katie Mack. Photograph: Nerissa Escanlar

Human beings tend to centre ourselves as the cause of and solution to most problems. This one, Mack says, shakes us so deeply because “we want to be the hero in the story, or at least the main character. The idea that that doesn’t matter to these forces that sweep over the universe is hard for our egos.”

In a very 2020 set of circumstances, the publication of The End of Everything was delayed due to the coronavirus pandemic. Mack had concerns that the book might feel too weighty given the general pall under which we have all been living this year.

“I have worried that maybe the book casts a gloominess and apocalyptic tone that people don’t feel they need right now” she says. “The original idea was that it would come out before the presidential election and that cheerful nihilism would be a fun relief. We are all used to the kind of terrible that politics is, but we aren’t used to the kind of terrible that a pandemic is. The level of suffering and pain has been so high, so I have worried, but the book is, despite appearances, actually quite light.”

Mack does manage to write about our impending doom with a sort of ironic levity that ultimately contextualises what might be considered the frightening lack of relevance human beings have in the grander reality.

She is something of an anomaly in her field. She’s gregarious; excited by the prospect of translating her expert knowledge into a form that can be shared with non-experts. She is not a classic academic, horrified by the idea of “dumbing down” concepts for normal people. Quite the contrary, Mack has grown an enormous social media following by engaging widely with the public and presenting physics as something for all.

Mack works in the theoretical side of things these days, she says, though the book references both a fire (a “quite small one”, she stresses when I ask about it) and an explosion while she was training; neither incident, she labours to emphasise in the book, was her fault.

She leaves the references dangling spicily in the book, so I ask for the stories and can confirm that there isn’t a court in the land that would convict her. She prefers the creativity of theory, and was drawn to the topic of the book mostly because “it’s just so very weird, such a fascinating notion that technically it could all end at any moment, though of course that last bit is incredibly unlikely.”

What meaning might we take from the prospect of the end of the universe? This is something Mack herself says she has wrestled with. Mack can’t and doesn’t ultimately offer a salve for those wounds – after all, it isn’t really her job to do so. She is hopeful, though, that “people might find it a nice distraction, since we have all been swept up in this thing – this pandemic – that is so much bigger than we are. It would be good if the book can help some people to have the perspective it’s helped me to have – just to appreciate what you have in the moment even if it’s impermanent, and even if we don’t know what’s going to happen.”

Of course, the end of it all will likely happen on a timescale that is so distant as to be irrelevant to most people. Physicists don’t really think about time the way the rest of us do, so Mack is still “not super chill about it”, she chuckles.

“I’m quite disturbed by the thought of death, and of everything that has meaning to human beings just ceasing to exist. But it has given me a better sense of the transience of my own life, and that you have to find ways for things to matter as they happen, while they exist. I don’t know if it all only matters if it lasts forever, but I do know that it has to matter now”.