Katie Mack, an assistant professor of physics at North Carolina State University, is quickly becoming one of the internet’s most popular science communicators. In her first book, The End of Everything (Astrophysically Speaking), she explores various scenarios for the end of the universe.
“I noticed that when I gave public talks and talked about the end of the universe, that was something that people got really excited about,” Mack says in Episode 430 of the Geek’s Guide to the Galaxy podcast. “It was something that I thought I could have a lot of fun with, and I did. I really enjoyed writing this book.”
Science fiction writers have long been fascinated by the end of the universe, and both Tau Zero by Poul Anderson and The Restaurant at the End of the Universe by Douglas Adams involve characters who witness the end of everything. Both of those books, published in 1970 and 1980 respectively, assume a Big Crunch model of cosmology.
“The Big Crunch would be interesting to see,” Mack says. “The expansion of the universe stops, and reverses, and everything comes crashing back together. It would be kind of a neat light show, though it would also be super-lethal for anything that’s out there.”
Unfortunately for science fiction fans, the current thinking among scientists is that the end of the universe will be pretty boring. “We’re probably not going to have a Big Crunch,” Mack says. “It’s probably going to be the Heat Death, where the universe just continues to expand and expand, and things sort of fade away. So in principle it might not end up being that interesting, because you’d get there and all there is is just lots of cold, dark, empty space.”
Given that the end of the universe will be sort of a letdown, Mack says a journey to the near future sounds far more appealing.
“I’d much rather see a hundred years from now, and then a thousand years from now, and kind of step forward that way, and not go straight to the ending, because I don’t think the ending is going to be fun.”
Listen to the complete interview with Katie Mack in Episode 430 of Geek’s Guide to the Galaxy (above). And check out some highlights from the discussion below.
Katie Mack on the Star Trek episode “Remember Me”:
“Very strange things are happening on the ship, and people are disappearing, and the universe seems to be getting smaller around [Dr. Crusher]. She’s a doctor, so she knows that she could be hallucinating all this, and so she does diagnostics on herself and there’s nothing wrong, her mind is working perfectly. So she concludes that if there’s nothing wrong with her, there must be something wrong with the universe. … I use that as a way to introduce the possibility that the reason we find the force of gravity to be so weak is not that there’s something wrong with gravity per se, but that the universe might be a different shape than we anticipated—might have a different number of dimensions than we anticipated—and that could be why gravity seems so weak. So it’s not something wrong with gravity, it’s something wrong with the universe.”
Katie Mack on social media:
“Once in a while a tweet goes viral, and then a whole bunch of people see it and a whole bunch of people follow you. The biggest example of that was in 2016 where somebody was complaining about climate change, and tweeted to me about it, and I replied to that in a way that got a lot of attention. I had been tweeting about how climate change is depressing, basically, and somebody replied and said that climate change is a scam, and said, ‘You should go learn some science.’ So I replied that I already got a PhD in astrophysics, and more than that seems like it would be overkill. Somehow that got picked up by a bunch of people and retweeted a whole lot, and then J.K. Rowling took a screenshot of it and posted it on her feed, and that just blew up my Twitter. I think my following doubled in a week.”
Katie Mack on long-term survival:
“In only about 4 billion years the Andromeda Galaxy will collide with this one, which will make a mess—it’ll move the orbits of stars around, and there’ll be some new star formation, and the supermassive black holes will merge, and that could cause some jets of high-energy radiation, but it won’t necessarily affect the solar system all that much. It’ll move where we are in the galaxy, and change our night sky, but it’s not going to hurt us, necessarily. Even the amount of star formation that you’ll get out of that collision—it’ll be enough to set off some new supernovae, but it won’t necessarily hurt us. So I think we can survive that pretty easily, and then after that it’s just a matter of slow cooling, where everything’s just kind of fading away for billions and billions and billions of years.”
Katie Mack on Freeman Dyson:
“You want to use less and less energy over time, because you’re going to have access to less and less energy as the universe is expanding and cooling. The whole point of [Dyson’s] exercise was to figure out if there was a way to slow down your processes as the universe is expanding, to the point that you can live technically forever—it’s just that over time each thought gets farther and farther apart. That would work if the universe were expanding linearly, meaning that it was not speeding up in its expansion, but we know now that the universe is speeding up in its expansion, and that does mess up that plan, in a kind of complicated way. So that doesn’t work indefinitely, but it can still buy you some time, if you need to just conserve resources over a very long period of time in the cosmos.”
