Cosmologist Katie Mack Explores End-of-the-Universe Scenarios | CBC radio

Cosmologists aren’t sure how the universe will end, but they’re pretty confident it will. Since it had a beginning, it will also have an end.

In about five billion years, the sun will scorch the earth to a crisp unless humans finish the job before the sun has a chance.

Katie Mack is a theoretical astrophysicist at the Perimeter Institute for Theoretical Physics in Waterloo, Ontario. She studies the possible fates of the universe.

In her book The end of everything (astrophysically speaking)She explores the intriguing science behind various end-of-universe scenarios and also reflects on the meaning of existence when nothing – not even the universe – lasts forever.

Mack spoke up IDEAS Hostess Nahlah Ayed on the theories of the eventual end of the universes.

Here is a short excerpt from their conversation:

They talk about Big Crunch, Heat Death and Vacuum Decay – they all sound so apocalyptic. But there is another apocalyptic possible fate of the universe that you write about called The Big Rip. Can you briefly explain what that is?

The Big Rip is one way dark energy goes wrong.

Dark energy is mysterious stuff that seems to be present throughout the universe, making the universe expand faster. And our best guess right now is that it’s a cosmological constant. It’s something that’s just a property of space.

But if it’s something that changes over time and gets stronger over time, if the amount of dark energy and every bit of space builds up over time, then not only is it moving galaxies away from each other, it’s starting to stretch galaxies from Inside. It begins to build up inside objects, inside bound structures like galaxies and solar systems, but also solid objects like planets and stars.

And you can calculate that the way it affects the universe as a whole is that it expands and expands and expands rapidly, to the point where you calculate a datum based on certain properties of the theory be able. You can calculate a point in time in the future when the entire universe would be torn apart. This is the big crack.

While unlikely based on what we understand about how dark energy might work or our understanding of the possibility of what dark energy might do, the data doesn’t rule it out. It’s about understanding dark energy, and we don’t understand dark energy. We have some ideas about dark energy, but we don’t really know what it is.

I wonder what the impact is of working into it – and hearing those kinds of possibilities of the end of the universe. I mean, as you say, some of these models have actually outlasted the universe for billions more years. It feels like an eternity, but it’s not an eternity. How unsettling or unsettling do you and other scientists and people in general find the idea that the universe just won’t last forever?

I went around asking my colleagues about it as part of the book. I asked her about the science of these different possibilities and the observations needed to set boundaries and the like. And in every interview I made sure to ask: How does the end of the universe feel inside you? What does that mean for you personally?

There was a wide range of answers. Some people said it’s ok, we should be temporary. It’s just a part of life. Some people said it was a really disturbing idea — and some of the people who said it was a really disturbing idea were actively working on possibilities involving a continuation of some kind of cyclical universe.

A lot of people find it very disturbing, the idea that we don’t last forever, even though we’re forever talking about something so far in the future that it’s unimaginable. There’s still something visceral about the idea of ​​all this being destroyed. And everything we have seen, everything we have experienced will end and we will have no legacy for the future. I think that’s more troubling than other aspects because when I think about my own death, I think I’m going to die. Everyone dies.

But I will have done something. I will have contributed to my area. I have written a book. Maybe I made someone’s life better – and other people might say, “I built this amazing building,” or “I had kids who did amazing things,” or whatever.

People have a legacy that is important to them when they think they are nearing the end of their lives. And when the universe ends, none of us will have any legacy at all… But there will come a time when all human endeavors will be extinguished. And I find that particularly disturbing.

You say that’s an observation or is that your feeling too?

It’s my feeling too. I don’t like the idea. I don’t want the universe to end – I like it here. So yeah, it’s a confrontation for me too. One of the things I talk about in the book is trying to grapple with it myself, with the idea that we don’t last forever and that nothing we do lasts forever.

And what I learned from that is that you have to find some kind of meaning in the universe that doesn’t depend on the future. You have to create meaning yourself, make the universe matter in some way, and find purpose without relying on “Oh, everything will be fine in the end” because it might not be.

*Questions and answers edited for clarity and length. This episode was produced by Chris Wodskou.