The LIUniverse with Dr. Charles Liu

• Black Holes Colliding with Dr. Charlotte Olsen

  How do very small galaxies form? What’s going on inside them? And what happens when black holes collide? To find out, Dr. Charles Liu and co-host Allen Liu welcome astrophysicist and “Galaxy Detective” Dr. Charlotte Olsen from New York City College of Technology – and you can call her Chuck, too! As always, though, we start off with the day’s joyfully cool cosmic thing, the latest announcement from LIGO about the detection of a gravitational wave event in 2023 from the loudest collision we’ve heard so far. In this case, the wave was caused by the collision of two black holes that created one new black hole about 60x the mass of our Sun and released an entire sun’s worth of energy. Charlotte explains why there are many black hole collisions going on, and how LIGO detections are now being combined with data from other gravitational wave detectors to give us more precise measurements. You’ll also hear about Active Galactic Nuclei (AGNs) and their negative impact on Charlotte’s research. Charlotte talks about what she looks for in her research, and why it all comes down to “wanting to see more photons” to better validate her modeling. Our first question from the audience comes from Joe, who asks, “What does it mean for the Milky Way to have a bar? Why does it have a bar? And how can such a long bar form?” It turns out that many spiral galaxies like ours have bars, and Charlotte explains a little about bar structure. She brings up the current debate about the stability of these bars, and points out that they actually come in slightly different configurations and that star formation at the ends of the bar has an impact, too. Unlike previous thinking, these bars can develop earlier in galactic evolution and can last a very long time. In other words, as Charlotte puts it, “The bar is always open.” Next, Chuck asks what got Charlotte into astronomy. She describes the inspiration she drew from both the dark skies of Northern California, where she grew up, and from the science fiction she read. She shares a few of her “million and one jobs” she did, including her stint as a bassist in a band. That tees up our next audience question, from Shivani, who asks, “How do you mix music and science? I can't decide if I want to be a scientist or a musician someday – can I be both?” Yes, Charlotte says, and explains why doing both might actually be better. She talks about the value of music, and passion, and hobbies that are more than just hobbies, as well as some of the live music she’s been seeing in Brooklyn, Long Island and Queens. Finally, Chuck asks Charlotte about the current passion project she’s working on. She tells us how she’s looking at a handful of galaxies in multiple wavelengths and comparing them to each other to figure out “what’s going on under the hood.” If you’d like to know more about Charlotte, you can connect with her on Bluesky at @charlotteeureka.bsky.social or on her GitHub page charlotteolsen.github.io. 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: Visualization of a binary black hole merger consistent with the gravitational-wave event called GW250114. (Note: this is to illustrate the collision of 2 black holes and the subsequent gravity waves generally, it is not specific to the GW230814 event Chuck mentions in the episode) – Credit: H. Pfeiffer, A. Buonanno (Max Planck Institute for Gravitational Physics), K. Mitman (Cornell University) Animation of an active galactic nucleus. – Credit: NASA, ESA, and the Hubble SM4 ERO Team. Hubble Space Telescope image barred galaxy NGC 1300. – Credit: NASA, ESA, and The Hubble Heritage Team STScI/AURA Data from NASA's Wide-field Infrared Survey Explorer (WISE) used to trace the shape of the Milky Way's spiral arms. – Credit: NASA/JPL-Caltech #liuniverse #charlesliu #allenliu #sciencepodcast #astronomypodcast #charlotteolsen #blackholes #ligo #gravitationalwave #blackholecollisions #activegalacticnuclei #agns #milkyway #spiralgalaxies #barredgalaxies

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• Measuring the Stars with Astrostatistician Sabrina Berger

  How does a star form? How does the universe form? And how can we use every bit of astronomical data to answer those questions? To find out, Dr. Charles Liu and co-host Allen Liu welcome astrostatistician Sabrina Berger, all the way from Melbourne, Australia, where she’s currently pursuing her PhD. As always, though, we start off with the day’s joyfully cool cosmic thing, the new radioastronomy photographs of Callisto, one of the moons of Jupiter, taken by ALMA. Sabrina talks about her own low-frequency radio astronomy research looking for hydrogen in the very early reionization period of the universe when the first galaxies were forming. (Be warned: we dive into the difficulties ionization poses for trying to discern these early processes, including a side trip into quantum mechanics, the hyperfine transition of neutral hydrogen at 21cm depicted on the plaque attached to the Pioneer spacecraft, and even the Cosmic Background Radiation.) You’ll also hear how Sabrina is innovatively using GPS satellites to help calibrate large radioastronomy telescope arrays. For our first student question, Derek asks, “I heard that black holes can form right after the Big Bang, before stars do. How is that possible?” Sabrina describes these primordial black holes, and, although none have been confirmed yet, that there have been a number of papers published recently on the subject. In fact, one paper suggesting that the as-yet-undiscovered “Planet 9” could even be one of these primordial black holes. And then, finally, we get to the subject of astrostatistics, Sabrina’s area of expertise. She explains that it allows you to harness every piece of information that you’re observing in astronomy and to answer questions like “How does a star form?” or “How does the universe form?” You’ll hear about huge data sets, the use of artificial intelligence, field level inferences… and the MCMC, or the Markov chain Monte Carlo used in statistics. (If you don’t know what that is, you’re not alone, and our own resident mathematician Allen helps Sabrina untangle the complexity with a cotton ball analogy that blew Chuck and Sabrina’s collective minds!) For our next student question, Wally asks, “Why is redshift one like nine billion years ago, bur redshift two only two billion years before that, and redshift three only one billion years before that?” As Chuck says, “that’s a little complicated,” just before he, Allen and Sabrina proceed to explain how we measure universal expansion, the passage of time, and the “stretching” of light. Our next conversation is one of the most controversial we’ve ever had and revolves around who Sabrina thinks makes the best espresso, Australia, Italy or a “Third Wave Coffee Shop” like we have here in the US. You’ll hear about why there’s an ISSpresso machine on the ISS – and how the Italian Space Agency invented a way to make an espresso in zero-g! Plus, you’ll hear a little about the work-life balance in Australia and how wonderful astronomy down under is. (Check out our Patreon for the story behind the Australian Aboriginal "Emu-in-the-sky" constellation.) If you’d like to know more about Sabrina, you can find her on Twitter and Blue Sky @sabrinastronomy or check out her research on her website. 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: An image of Jupiter's icy moon Callisto, photographed by NASA’s Galileo spacecraft in 2001. – Credit: NASA/Galileo Photograph of Jupiter taken in 2019. The four fainter objects are four of its moons (left to right): Callisto, Ganymede, Io, and Europa. – Credit: Creative Commons / Rehman Abubakr ALMA images of Callisto – Credit: Maria Camarca et al 2025 Planet. Sci. J. 6 183. See the ALMA/Callisto paper: “A Multifrequency Global View of Callisto’s Thermal Properties from ALMA”: https://iopscience.iop.org/article/10.3847/PSJ/ade7ee Timeline of the universe. – Credit: NASA, ESA, CSA, STScI The Pioneer plaques, attached to the Pioneer 10 and 11 spacecraft. – Credit: NASA Sedna orbit with solar system (Sun, Jupiter, Saturn, Uranus, Neptune and Pluto visible) and positions on Jan 1, 2017 – Credit: Creative Commons / Tom Ruen Redshift and universe expansion. As light travels from great distances to Hubble's mirrors, it is stretched to longer and longer red wavelengths, or cosmologically redshifted, as the universe expands. – Credit: NASA, ESA, Leah Hustak (STScI) The ISSpresso machine on the International Space Station.– Credit: NASA Astronaut Samantha Cristoforetti drinking espresso out of the cup on ISS, 2015 – Credit: NASA #liuniverse #charlesliu #allenliu #sciencepodcast #astronomypodcast #sabrinaberger #astrostatistician #astrostatistics #redshift #blackholes #primordialblackholes #callisto #alma #planet9 #sedna #universeexpansion #isspresso

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• Cosmic Raspberries and Life on Mars with Dr. Kelly Blumenthal

  Have we discovered life on Mars? What does the center of our galaxy taste like? To find out, and to kick off Season 5 of The LIUniverse, Dr. Charles Liu and co-host Allen Liu have reached out all the way to Tokyo to chat with Dr. Kelly Blumenthal, the Director of the International Astronomical Union Office for Astronomy Outreach. As always, though, we start off with the day’s joyfully cool cosmic thing, a rock found in Sapphire Canyon by the Mars Perseverance Rover containing potential biosignatures. Allen explains why this rock is different: iron and sulfur nodules that exhibit indications of layers which, on Earth, could only be formed by bacteria. Kelly points out that there needs to be more investigation before we can say anything for sure. Chuck asks Kelly, who when she was 12 told her dad that she wanted to study galaxy evolution, to describe the research she did at the start of her career. She talks about studying with pioneering astronomer Joshua Barnes in Hawaii during her Masters projects and PhD. For her first project, she studied star formation rates in Jellyfish Galaxies, which are being ram-stripped of their gases and so appear to have tendrils. She ended up looking at the history of merging galaxies through cosmic time using large cosmological simulations. Then it’s time for our first student question of Season 5, from Jeannie, who asks, “Now that we’ve found so many planets outside of our solar system, should Pluto be promoted as a planet again?” (Pluto’s “demotion” nearly 20 years ago was traumatic for some.) According to Kelly, though, the “demotion” was really a reclassification, and at least for the time being, Pluto is going to stay a dwarf planet, a new category of which it was the first of its kind. She contrasts Pluto to the moons of Jupiter and reminds us of the new rules about what’s a planet and what’s not. Kelly brings up Star Trek and therefore gives Chuck permission to geek out over “Devil in the Dark” from the Star Trek: The Original Series, and “Silicon Avatar” from Star Trek: The Next Generation. Kelly talks about bingeing sci-fi in high school including 2001: A Space Odyssey, and the Foundation series, and more recently, The Expanse series, which she’s listened to three times as audio books! Chuck and Kelly discuss communicating about science, and even the role science fiction can play. Kelly talks about the importance of understanding your audience. She uses the example of explaining what nebulas look like through the Chandra X-Ray Observatory to a blind and low-vision audience. Kelly also talks about how you can approach science through poetry, music, dance, theatre and art – even smell. She recalls a talk where someone working with incarcerated kids, who was limited in what props they could bring, made the universe come alive for them using the scent of raspberries, which have a similar chemical signature as the center of our galaxy. For our next audience question, Bridget asks, “So is that comet actually an interstellar spaceship?” Kelly debunks the notion that Comet 3I/ATLAS is anything other than a rock that’s come from outside our solar system and explains why extrasolar asteroids are amazing things. We end with a discussion of the IAU’s upcoming, worldwide “100 Hours of Astronomy” on Oct. 2-5, 2025, including a 24-hour live stream on Oct. 4 from the oldest functioning planetarium in Japan. Watch it live on YouTube via the IAU Office for Astronomy Outreach @IAUoutreach here.  You can also visit their website at https://iauoutreach.org/, follow IAU Office for Astronomy Outreach on Facebook and LinkedIn, and on Instagram @oao_iau. If you have any questions, email them at [email protected]. You can follow Kelly on LinkedIn.  We hope you enjoy the Season 5 premiere of The LIUniverse. Please support us on Patreon. Credits for Images Used in this Episode: Observatory History Museum at NAOJ in Mitaka – Credit: おむこさん志望, CC BY 3.0 “Sapphire Canyon” sample – Credit: NASA Perseverance Rover Iron Bacteria in Scotland – Credit: Roger Griffith Jellyfish Galaxy ESO 137-001 – Credit: NASA/ESA/CXC Jellyfish Galaxy JO201 – Credit: ESA/Hubble & NASA, M. Gullieuszik, CC BY 4.0 New Horizons probe before launch – Credit: NASA Pluto’s “Heart”, Tombaugh Regio – Credit: NASA / Johns Hopkins University Applied Physics Laboratory / Southwest Research Institute Chandra X-ray Observatory (Illustration) – Credit: NASA/CXC/NGST Interstellar Comet 3I/Atlas – Credit: International Gemini Observatory/NOIRLab/NSF/AURA/Shadow the Scientist, CC BY 4.0 Artist’s illustration of interstellar asteroid 1I/'Oumuamua – Credit: NASA, ESA, Joseph Olmsted (STScI), Frank Summers (STScI) Interstellar Comet 2I/Borisov – Credit: NASA, ESA, and D. Jewitt (UCLA) 100 hours of Astronomy! – Credit: IAU, CC BY 4.0 #liuniverse #sciencepodcast #astronomypodcast #kellyblumenthal #lifeonmars #bacteria #jellyfishgalaxy #pluto #interstellarasteroid #comet3iatlas #iau #officeforastronomyoutreach #startrek #theoriginalseries #thenextgeneration #theexpanse

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• Chuck GPT Apocalypse, Part 2

  It’s the end of everything! Welcome back to Part 2 of our season finale featuring Dr. Charles Liu, co-host Allen Liu, and our guest archaeology expert and author, Hannah Liu, MEd. (If you haven’t caught up to Part 1, we highly recommend you do before embarking on the next leg of this journey! Listen here or wherever you get your podcasts!) We pick right up where we left off, with the next question from our audience. Daniela asks, “If a black hole hits the Sun, will Earth be destroyed?” Chuck explains a few ways a black hole can mess with our day, including the fact that long before any actual collision took place, the Sun would start shedding material that would destroy us. He compares that unlikely event to the actual example of cosmic destruction we’re watching in NGC 4676 – aka “The Mice” – which are two galaxies swirling together in a death spiral playing out over hundreds of millions of years. Naturally, this leads Chuck to ponder what happens when civilizations fall apart here on Earth, and Hannah brings up the collapse of the Roman Empire. As she explains, “the fall of Rome happened a lot of times, and also, no time.” From 44 BCE and the assassination of Julius Caesar, to the 476 invasion and conquest of Rome by the Germanic tribes denoted by Edward Gibbon in The History of the Decline and Fall of the Roman Empire, to the fact ever since nations have claimed to be the descendants or inheritors of Rome. Chuck points out the influence of Gibbon’s book on Isaac Asimov’s “Foundation” series, followed by a very quick romp through “Decline and Fall of America” literature including The Handmaid’s Tale, A Canticle for Liebowitz, Man in the High Castle, and the zombie apocalypse tour de force, World War Z. Then it’s time for another question from the audience: Michael says, “I heard that scientists brought back a dire wolf. Could they bring back dinosaurs or animals that could destroy us all?” It turns out, these resurrected animals are just gray wolves that have been engineered to have some characteristics of the extinct predator. It’s still a pretty impressive feat, though, and you’ll hear how they collected bits and pieces of dire wolf DNA to “resurrect them.” Allen also brings up similar modification experiments they’re doing on chickens to make them more dinosaur-like. Allen points out that bioengineered germs are far more likely to cause our destruction than resurrected dinosaurs, regardless of the world envisioned in the Jurassic Park franchise. And speaking of Michael Crichton, Chuck gives us a breakdown of his sci-fi classic, The Andromeda Strain, about bacteria from space that cause a biological outbreak here on Earth. Hannah points out that historically, some of the biggest killers of human beings have been plagues. She gives us a guided tour of the bubonic plagues, from the Black Death, which may have wiped out as much as 60% of the population of Europe, to the Plague of Justinian a thousand years earlier that killed as many as 100 million people, while also name dropping the Antonine Plague and the Spanish Flu!) And that’s it Season 4 of The LIUniverse. Stay tuned for Season 5 after the summer. If you want to find out more about what Hannah’s impending book, check out the Mixed Identity Project  We hope you enjoy this episode, and this season, of The LIUniverse. If you did, please support us on Patreon Credits for Images Used in this Episode: NGC 4676, aka “the Mice” are two galaxies swirling together.  – Credit: NASA, H. Ford (JHU), G. Illingworth (UCSC/LO), M.Clampin (STScI), G. Hartig (STScI), the ACS Science Team, and ESA; The ACS Science Team: H. Ford, G. Illingworth, M. Clampin, G. Hartig, T. Allen, K. Anderson, F. Bartko, N. Benitez, J. Blakeslee, R. Bouwens, T. Broadhurst, R. Brown, C. Burrows, D. Campbell, E. Cheng, N. Cross, P. Feldman, M. Franx, D. Golimowski, C. Gronwall, R. Kimble, J. Krist, M. Lesser, D. Magee, A. Martel, W. J. McCann, G. Meurer, G. Miley, M. Postman, P. Rosati, M. Sirianni, W. Sparks, P. Sullivan, H. Tran, Z. Tsvetanov, R. White, and R. Woodruff. Plaster replica of Statue of George Washington by Antonio Canova at the North Carolina Museum of History.– Credit: Creative Commons / RadioFan (talk) Dire Wolf Cover of TIME magazine, May 12, 2025. – Credit: TIME magazine Page Museum Display of 404 dire wolf skulls found in the La Brea Tar Pits. – Credit: Creative Commons / Pyry Matikainen The spread of the Black Death in Europe, 1346-1353. – Credit: Creative Commons / Flappiefh - Own work from: Natural Earth ; Cesana, D.; Benedictow O.J., Bianucci R. (2017). Yersinia pestis, the bacterium that causes the Plague. Direct Fluorescent Antibody Stain (DFA), 200x. – Credit: CDC 2057 - US Government public domain image, Courtesy of Larry Stauffer, Oregon State Public Health Laboratory Little Ice Age Temperature Chart. – Credit: Creative Commons / RCraig09 - Own work #liuniverse #charlesliu #allenliu #hannahliu #sciencepodcast #astronomypodcast #hannahliu #apocalypse #armageddon #doomsday #ngc4676 #themice #blackhole #romanempire #direwolf #bubonicplague #blackdeath #yersiniapestis #theandromedastrain #michaelcrichton #jurassicpark #littleiceage

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• Chuck GPT Apocalypse, Part 1

  As our fourth season draws to a close, we’ve got an apocalyptic, 2-part ending lined up. That’s right, we’re talking Armageddon, and we don’t mean the 1998 Bruce Willis blockbuster. And of course, if we’re going to delve into the end of everything, Dr. Charles Liu and co-host Allen Liu are going to need the help of our ever popular archaeology expert and author, Hannah Liu, MEd. As always, though, we start off with the day’s joyfully cool cosmic thing, the failed Soviet-era Kosmos 482 lander that was designed to withstand entry into the Venus atmosphere but never actually let Earth orbit and finally just came crashing back home on May 10, just a few days after we recorded this episode! Chuck, Allen and Hannah ponder the possibilities of cataclysmic destruction that the more than half-ton object could produce. Then, without missing a beat, Hannah takes us all the way back to Greek mythology and the Titanomachy, the legendary fights between the Gods and the Titans that were possibly inspired by catastrophic volcanic eruptions that laid waste to the ancient Mediterranean. Chuck jumps continents to discuss the Norse apocalypse known as Ragnarök – casually dropping that is inspired the massively popular Baldur’s Gate 3 as he does. Not to be outdone, Hannah brings us all back to the original Armageddon itself: the final battle between good and evil that is foretold in the Book of Revelations to take place at Har Megiddo, the “Hill of Megiddo” in Hebrew. You’ll also hear about where the word apocalypse comes from, and why it’s become associated with the end of the world, as Hannah gives us all a quick lesson in eschatology, or the study of the end of the world. Our first question comes from Ahmed, who asks, “What are the odds that a killer asteroid will kill us all?” Allen gets a little excited about asteroid 2024 YR4, an asteroid the size of a 15-story building, that is predicted to pass safely by Earth in 2032 but at one point had as high a chance of hitting us as 4-5% – and still has about a 3% chance of hitting the Moon. Chuck explains that the odds of a true “dinosaur-killer” extinction event asteroid impact from an object at least a mile across is about 50 million to 1 in any given year. Hannah points out that it’s far more likely that Mount Vesuvius, the volcano that inundated Pompeii, will erupt again. The last one was in 79AD, and since it tends to blow its top every 2,000 years or so, we’re due. Moving back further, Hannah tells us about the Minoan Eruption that devastated the isle of Santorini in the Mediterranean, wiping out the city of Akrotiri, around 1600 BCE and was reported as far away as China. And that’s just a few of the disastrous historic collapses Hannah shares with us, including the Hekla 3 eruption in Iceland that had may have had something to do with the Bronze Age Collapse. It turns out that the apocalypse is too big for a single episode! Join us in two weeks for Part 2 of our journey into all things apocalyptic. 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: The Kosmos 482 lander probe reentered Earth's atmosphere on May 10 at 06:24 UT over the Indian Ocean. Because the Russian probe was designed to withstand entry into the Venus atmosphere, it is possible it survived reentry, but has landed in the ocean west of Jakarta, Indonesia.– Credit: NASA On March 26, 2025, NASA’s James Webb Space Telescope captured images of asteroid 2024 YR4 that indicate the asteroid is about the size of a 15-story building. – Credit: NASA, ESA, CSA, STScI, Andy Rivkin (APL) Santorini island, Greece. Satellite image of Thera. The bay in the center of the island is the caldera created by the Minoan eruption.– Credit: NASA EOS Excavation of Akrotiri in 2018– Credit: Creative Commons: By Rt44 - Own work The Bull-Leaping Fresco from the Great Palace at Knossos, Crete – Credit: Creative Commons / Gleb Simonov Detail of Abraham Ortelius' 1585 map of Iceland showing Hekla in eruption. The Latin text translates as "The Hekla, perpetually condemned to storms and snow, vomits stones under terrible noise". – Credit: Creative Commons / Abraham Ortelius #liuniverse #charlesliu #allenliu #hannahliu #sciencepodcast #astronomypodcast #hannahliu #apocalypse #armageddon #doomsday #kosmos482lander #asteroid2024yr4 #titanomachy #ragnarak #baldursgate3 #bookofrevelations #harmegiddo #eschatology #mountvesuvius #pompeii #minoaneruption #hekla3 #bronzeagecollapse

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