The LIUniverse with Dr. Charles Liu

Why is star formation the workhorse of the universe? What is a flocculent galaxy? Which cosmic cataclysm creates new globular star clusters? And why are we currently seeing such amazing aurora in unusual places? To find out, Dr. Charles Liu and co-host Allen Liu welcome astronomer Dr. Kelsey Johnson, past president of the American Astronomical Society (AAS) and of the Astronomical Society of the Pacific (ASP), and author of “Into the Unknown – The Quest to Understand the Mysteries of the Cosmos.” As always, though, we start off with the day’s joyfully cool cosmic thing, the auroras that have been occurring during the peak of the current solar max period of the roughly 11-year-long solar cycle. From the Mother’s Day aurora borealis in May to the amazing night of October 10, when millions of people as far south as Florida and Mexico were treated to one of the most spectacular, vibrant light shows many of them had ever seen. Kelsey shares the story of the first time she saw an aurora, as a high school student in Minnesota who didn’t even know what one was. Upon leaving her boyfriend’s house at around 2 in the morning, she saw a brilliantly glowing sky. Kelsey’s availability bias kicked in, and her assumption was that it had to be either god or aliens, with the latter being the more likely. Needless to say, the next day the front page of the local paper solved the mystery. And then it’s on to a nerdy discussion of existential curiosity, deep, philosophical questions, and her book, “Into the Unknown.” You’ll hear what drove Kelsey to write the book, and about her lifelong drive to understand our place in the universe. Kelsey and Allen nerd out over Calabi-Yau manifolds (concepts from string theory), imaginary numbers and complex numbers, Euler’s Formula and more, and then, thankfully, it’s time for our first question. Johnny asks, “What is a flocculent galaxy, and why are they interesting?” Kelsey says that they’re spiral galaxies with spiral arms that aren’t very pronounced, that are exceptionally “floofy and chaotic” with very different, but very cool star formation. Chuck and Kelsey explain why star formation is the workhorse of the universe and how important it is. Kelsey also explains why globular clusters are her “favorite” type of star cluster. There are about 150 of them living around our galaxy, and they’re almost as old as the universe itself, over 10 billion years old. Kesley studies them to learn how the universe was formed and how galaxies came together. New globular clusters are rare, but they can be created by the collision of two galaxies. That’s all we could squeeze into Part 1, but come back in two weeks for Part 2 of "Into the Unknown with Dr. Kelsey Johnson." If you’d like to know more about Kelsey, you can visit her website at and follow her on Twitter (X) and Instagram at @ProfKelsey, 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: Graph of the solar cycle – David Hathaway, NASA, Marshall Space Flight Center, Public Domain May 2024 aurora in Northern Ireland – David Kernan, CC BY May 2024 Aurora from Chihuahua, Mexico – Levi bernardo, CC BY Chuck & Allen’s view of the October 2024 aurora – Allen Liu Eugenio Calabi and Shing-Tung Yau – National Science Foundation, Public Domain Eugenio Calabi and Shing-Tung Yau – Konrad Jacobs 3D model of a Möbius Strip – Inductiveload, Public Domain 3D model of a Klein bottle – Lukáš Hozda, Public Domain Number line – Rumil, Public Domain Complex Plane – Brigban, Public Domain NGC 2775, a flocculent galaxy – European Space Agency, CC BY Messier 2, a globular cluster – NASA Hubble, CC BY #TheLIUniverse #CharlesLiu #AllenLiu #SciencePodcast #AstronomyPodcast  #KelseyJohnson #AAS #ASP #IntotheUnknown #aurora #solarmax #CalabiYaumanifolds #stringtheory #imaginarynumbers #complexnumbers #flocculentgalaxy #spiralgalaxy #globularclusters #starformation #starcluster

Happy Halloween! In this special episode of The LIUniverse, Dr. Charles Liu and co-host Allen Liu welcome back archaeology expert Hannah Liu, MEd to bring a scientific eye to the holiday and some of its most familiar denizens: witches, werewolves, zombies, black cats and even the Great Galactic Ghoul! As always, though, we start off with the day’s joyfully cool cosmic thing: Comet C/2023 A3 (Tsuchinshan-ATLAS). You’ll learn all about this visitor from the Oort Cloud, including how we know where it came from. Hannah talks about how ancient people responded to the arrival of a comet, including how leaders have used them for their own political purposes, and Charles brings up the inclusion of Halley’s Comet on the Bayeux tapestry. Then it’s time for Chuck to introduce our theme for this special episode: how the superstitions of the past interact with the mysteries of science. You’ll hear from Hannah about the history of Halloween and its beginning as the Druidic celebration of Sawen (or Samhain) marking the end of the harvest season. Jumping ahead in history, we look at the Salem Witch Trials of the 17th Century, and the “science” that was used to condemn innocent young women to death for behaviors the powers that be disapproved of. You’ll also get serious answers to spooky questions like “Do full moons affect behavior?” (We’re talking the behavior of moths, sea turtles and humans, rather than werewolves, although we do actually get into the possible origins of the wolfman myth as embodied in the Greek myth of Zeus and Lycaon with a minor digression into D&D and legendary DJ Wolfman Jack.) After witches and werewolves, what else could we talk about next than zombies? In this case, natural zombie spiders created by the sting of a parasitic Tarantula Hawk wasp, or zombie ants that have been infected by the fungus Ophiocordyceps unilateralis. And yes, somehow The Walking Dead and The Last of Us shamble into the discussion, although regarding the latter, Allen explains why cordyceps probably couldn’t survive in a human host. Next up, we look at the connection between black cats and the holiday. Hannah brings up the traditions of cats as “Witch’s Familiars” and shapeshifters, and Chuck reminds us of the moment when we saw a cat transform into Professor McGonagall in Harry Potter and the Sorcerer’s Stone. You’ll hear about how STS-13, which was slated to be the thirteenth mission of the Space Shuttle, was renamed STS-41-C, in an attempt to avoid any superstition or reminder of the ill-fated Apollo 13. There was an alternate mission patch that featured an illustration of the shuttle landing under a giant black cat, referencing the mission's original designation, STS-13; and that the day the mission returned was April 13, 1984, which was a Friday the 13th. Speaking of space, Hannah asks Chuck about the concept of “The Great Galactic Ghoul,” the fictitious space monster blamed for the failure of nearly every probe sent to Mars by the Soviet Union, Japan, and even NASA between 1988 and 1999. Out of 10 missions, only 2 US probes landed successfully on the Red Planet. Since then, while the Ghoul did claim a few more victims including two missions by the UK, it seems to have gone into hiding, since the US has had multiple successful missions, as has China with their Tianwen lander and Zhurong rover, India, Russia, the European Space Agency, and the UAE. Finally, to end our special HaLIUween episode, Chuck brings up Albert Einstein’s term, “Spooky Action at a Distance,” which he coined derisively to describe the physics concept known as quantum entanglement that he dismissed but has since been proven to exist. We hope you enjoyed this special episode of The LIUniverse, and, if you do, please support us on Patreon. Credits for Images Used in this Episode: Comet Tsuchinshan-Atlas – AlexL1024, Public Domain Diagram of the Oort Cloud – NASA, Public Domain Halley's Comet on the Bayeux tapestry – 11th century English embroiderers, Public Domain Irish hero Fionn fighting Aillen on Samhain – Beatrice Elvery, Public Domain Later depiction of the Salem Witch Trials – Joseph E, Public Domain Painting of the Aos Sí – John Duncan, Public Domain Ant infected with Ophiocordyceps unilateralis – Denis Zabin Tarantula Hawk wasp – Davehood, Public Domain STS-13 alternate mission patch –  Bp1222 Mars Climate Orbiter, unit error victim – NASA/JPL, Public Domain Purported face on Mars – Viking 1, NASA, Public Domain Better image of the same feature – NASA / JPL / Malin Space Science Systems, Public Domain China’s Tianwen lander and Zhurong rover – China News Service #TheLIUniverse #CharlesLiu #AllenLiu #HannahLiu #SciencePodcast #AstronomyPodcast #Halloween #Samhain #Sawen #witches #werewolves #zombies #blackcats #GreatGalacticGhoul #SalemWitchTrials #Ophiocordycepsunilateralis #zombieantfungus #TarantulaHawkwasp #STS13 #CometC2023A3 #CometTsuchinshanAtlas #HalleysComet #BayeuxTapestry

Welcome to Season 4 of The LIUniverse and thank you for joining us on this journey.   We’re kicking off the new season with another Chuck GPT episode devoted to answering your questions, and to do that, we’ve brought back archaeology expert Hannah Liu, MEd. She’s not alone: joining Dr. Charles Liu and co-host Allen Liu is The LIUniverse’s Social Media Guru, Stacey Severn.   As always, we start off with the day’s joyfully cool cosmic thing, Earth’s temporary second moon 2024 PT5. Don’t get excited, though, because it’s only the size of a school bus and won’t be visible to the naked eye. But it gives Chuck the chance to ask Hannah about the impact of celestial visitors in the past, and she tells us the story of Caesar’s comet (C/-43 K1) which showed up for about a week in the summer of 44 BCE – not long after the assassination of Julius Caesar. Allen also brings up the Great comet of 1680 and how it affected the development of astronomy.   Our first question comes from NSimplexPachinko, who asks, “During condensation of matter to 300,000 years after the Big Bang, did spacetime cease to expand, or did it continue expanding at the same rate as the energy within it?”   Short answer: Yes. For the long answer, you’ll have to watch or listen to the show for Chuck’s description (honed for the Intro to Astronomy class he teaches) of decoupling, expansion, universal evolution and “BIG, BIG, INFLATION!”   Stacey reads the next question from a listener in Poland. Pshemo Ziembora wonders, “The volume/length of space should be different for every observer depending on how fast they’re travelling or how strong the gravity field is. In other words, the speed of light will always be constant for each observer, but it may have a different value than 300,000 km/second. Distances on cosmic scales may vary due to your speed. When you are traveling faster in space your distance should be shorter. What am I missing?”   Chuck explains that Pshemo isn’t missing anything and has got it exactly right, describing the insight we now call the “Lorentz Contraction” which Albert Einstein built into his Special Theory of Relativity. Allen explains the physics involved, with an example that includes muons and cosmic rays and how different mediums can impact the speed of light.   Speaking of Poland, Hannah shares a story about licking the wall of the Wieliczka salt mine, which she visited on a trip there. For those of you watching, you can see a photo of one of the caverns hollowed out by the miners, with statues and scenic reliefs carved from the salt. There are no photos of the reported salt tasting.   Our next question comes from one of Chuck’s Astronomy 100 students: “Is Earth Intelligent?”   Chuck describes the Gaia Hypothesis, before the group grapples with the question. Hannah looks at the skepticism around the validity of that very hypothesis, and then takes a typical LIUniverse deep dive into Percy Jackson, and Greek and Egyptian mythology. Allen assesses Earth’s intelligence through the lens of Artificial Intelligence. Stacey brings up the concept that climate change is the Earth taking revenge on humanity for our actions, which Hannah relates back to Greek mythology, natural disasters, and the role of Demeter in bringing about winter.   Finally, “@I have an unoriginal name” asks, “How does the cyclic model of the universe deal with information not being destroyed.” And Andy Love wonders “about the quantum gravity issue. My thought is that gravity is emergent, from loop or string vibrations, where the outward pulse of the loop or string creates the atoms (Higgs field) and the inward pulse is gravitational force meaning there is no need for a new quantum gravity theory, gravity is already quantum.”   Both of those questions spawned some interesting and far-ranging conversations amongst the group (Can you say slinky cosmology and quantum gravity?) that would be impossible to summarize for you here, so just please watch or listen to the episode now!   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: – 2024 PT5’s orbit –NASA/JPL-Caltech – Public Domain – Caesar’s comet coin –From ~18 CE in modern Spain, – Public Domain – Comet C/2023 A3 Tsuchinshan-ATLAS – AlexL1024, Public Domain – Great comet of 1680 –Lieve Verschuier, Public Domain – Diagram of the universe’s expansion –NASA/WMAP Science Team, Public Domain – Refraction in a block of plastic –Ajizai, Public Domain – A muon’s view of Earth –The LIUniverse, derived from “Blue Marble” – Wieliczka salt mine –Rj1979, Public Domain – Gaia depicted on pottery –About 410 BCE, Public Domain – Statue of Demeter –Photo by Marie-Lan Nguyen, CC BY – Lord Kelvin’s Analog tide computer –Photo by Daderot, Public Domain – Svalbard Global Seed Vault –Frode Ramone, CC BY – ~1800 year old clothes preserved by a bog – Bullenwächter, CC BY – LIGO gravitational wave signals –Caltech/MIT/LIGO Lab, CC BY   #TheLIUniverse #CharlesLiu #AllenLiu #HannahLiu #StaceySevern #SciencePodcast #AstronomyPodcast #2024PT5 #CaesarsComet #SlinkyCosmology #QuantumGravity #comets #GreatCometof1680 #UniversalExpansion #muon #GaiaHypothesis #PercyJackson #GreekMythology #Egyptianmythology #AI #ArtificialIntelligence #cyclicmodeloftheuniverse #LorentzContraction #AlbertEinstein #SpecialTheoryofRelativity #archaeology

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).” In Part 2, we look at dark matter, Gravitational Memory Effect, and more. (You can listen to Part 1 here.) We dive right in with a question from David: “I was wondering if any physicists have looked into the idea that the “empty” space in an atom is actually “filled” with dark matter. What experiments could be done to prove or disprove this hypothesis?” In order to answer David, first Katie explains the science supporting the idea that dark matter exists, including gravitational lensing and other evidence. The fact that there are indications of dark matter in areas where there is sparse regular matter suggests that dark matter is an entirely different kind of particle. Katie describes many of the ways that that dark matter is unrelated to the empty space in atoms, including the fact that dark matter has no real interaction with atoms at all. Chuck asks whether the amount of dark matter still holds the key to how the universe evolves as he was taught or have new understandings made it entirely irrelevant? Katie explains that dark energy has replaced dark matter in importance, and that’s what’s making the universe expand faster. But we really don’t know what it is, or what it’s doing, or even if it will remain constant. Our next question comes from Aileen Balderas: “I recently read about something called the Gravitational Memory Effect. This talks about how space remembers certain things. Gravitational wave signals have the power to make it so that the universe remembers what happens to it. How can scientists say that the universe is able to remember things?” Katie unpacks this fascinating phenomenon which she only learned about five years ago. It turns out that, as Chuck puts it, “The universe has memory the way that memory foam has memory, not like the way elephants have memory.” Chuck asks Katie about flying planes, which she learned to do in late 2020 during the pandemic, after her book came out. Talk about a lockdown hobby! Katie shares why she loves flying so much, and what she gets out of it. And while she doesn’t own her own plane, she has a share in a single engine airplane with 4 other people. Chuck also asks the inevitable question: Star Trek or Star Wars? Katie’s answer: Star Trek! We end the show with Katie describing what she’s doing at The Perimeter Institute, an independent research institute that’s dedicated to stretch the boundaries of our understanding of physics in areas like cosmology, particle physics, quantum information and various areas of theoretical physics. Katie’s been working with them to create some short videos. Check out Perimeter Institute for Theoretical Physics on YouTube to watch "Quantum Physics 101" and "Cosmology 101." If you’d like to know more about Dr. Kathryn Mack and her work, check out her website, https://www.astrokatie.com/ where you can also sign up for her newsletter, “Watch this Spacetime.” You can also find her on Bluesky at astrokatie.com, Instagram and TikTok at @astrokatiemack, and Twitter (X), YouTube, and Facebook at @astrokatie. You can also find Katie on John Green’s “Crash Course Pods: The Universe” on Complexly, YouTube, Spotify, Simplecast and more. 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: Galaxy group "Stephan's Quintet" seen by NASA's James Webb Space Telescope – NASA, ESA, CSA, and STScI NGC 4826, otherwise known as M64— a spiral galaxy. – NASA / Hubble Heritage Team Hubble image showing light distortions from the collective gravity of dark matter. – NASA, ESA, and J. Lotz and the HFF Team (STScI) The expansion of the universe over time. – NASA The End of Everything (Astrophysically Speaking) – Scribner Dr. Katie Mack in the cockpit of her plane – Image via Katie Mack’s Instagram #TheLIUniverse #CharlesLiu #AllenLiu #SciencePodcast #AstronomyPodcast  #DarkMatter #DarkEnergy #UniversalExpansion #BlackHoles #EarlyUniverse #Spacetime #Physics #Astrophysics #Cosmology #GravitationalMemoryEffect #GravitationalWaves