How did the universe evolve, and more importantly, how might it end? To find out, Dr. Charles Liu and co-host Allen Liu welcome theoretical cosmologist and astrophysicist, Dr. Katie Mack, author of the recently published book, “The End of Everything (Astrophysically Speaking).” You’re going to need your thinking caps for this episode, because the trio get into some pretty intense and complex concepts in physics and astrophysics.

We start off this episode hearing why Katie, who grew up under the starless pink skies in LA, embarked on her journey to explore the very beginnings of existence itself. It turns out, it wasn’t the constellations or “pretty space pictures” that drew her to astrophysics, but the fact that all of the really cool, mindbending questions and extreme physics were related to stuff that happens in space like black holes and spacetime and “The Big Bang.”

For the day’s joyfully cool cosmic thing. Chuck, who studies Observational Galaxy Evolution, brings up a paper recently published in the Astrophysical Journal by Anna de Graaff et al, about the discovery, using the James Webb Space telescope, of a group of 13-billion-year-old dwarf galaxies with an unusually large amount of dark matter inside them compared to modern day galaxies. The researchers then used the Illustris cosmological simulation of galaxy formation to evolve those galaxies and found that they would end up with a percentage of dark matter that is consistent with dwarf galaxies today.

Katie talks about the value of simulations in the study of the galaxies and the early universe, especially as the simulations get better at exploring more physics, like Illustris does. The kinds of simulations she works with, though, are more simple models designed to capture the essential physics of galactic evolution.

She’s currently studying the possibility of dark matter annihilation in the early universe and what that would mean in terms of interacting with gas and energy as galaxies evolve. (At least, we think that’s what Katie’s talking about!)

Then it’s time for our first cosmological question for Katie. Ellis asks, “What’s your opinion on Block Universe theory?” Katie explains how the Block Universe theory attempts to model the past, present and future of spacetime, and how every point in space and time exists at the same time. (Again, we think that’s what she’s talking about!)

You’ll hear about physics equations that look the same forward and backward in time, the Second Law of Thermodynamics, relativity, causality, predetermination, the limits of observation, and the meaning of time itself.

Next, Chuck asks Katie about her book, “The End of Everything” and how she thinks the universe might end. The two discuss string theory, bouncing membranes, the ekpyrotic model of the universe, and other cyclical cosmological models. Katie shares how people often respond to her book from a theological perspective, including the idea of cyclical universes in religion.

Finally, this episode addresses the confluence of science, philosophy and faith, looking at life and death, religion and the divine, personal beliefs and the need many people have to find meaning in existence and possibly even objective truth.

Like we said, thinking caps! And that’s just Part 1. Join us in two weeks for the conclusion to our interview with Katie.

If you’d like to know more about Dr. Kathryn Mack and her work, check out her website, https://www.astrokatie.com/. You can also find her on Instagram and TikTok @astrokatiemack, and Twitter (X), YouTube, and Facebook @astrokatie.

We hope you enjoy this episode of The LIUniverse, and, if you do, please support us on Patreon.

Credits for Images Used in this Episode:

• TNG simulation (lines and shade) versus observations (symbols) – de Graaff et al. 2024


• Observers moving through a block universe – Jonathan Schooler/UCSB


• Model of two branes in extradimensional space that give rise to a cyclic universe. – Princeton University


• "The End of Everything (Astrophysically Speaking)" – Scribner

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