The LIUniverse with Dr. Charles Liu

• Shredding and Stitching Stars with u/Andromeda321 (Yvette Cendes)

  If a black hole shreds a star and nobody is around to hear it, does it make a sound? To find out, Dr. Charles Liu and co-host Allen Liu welcome Professor Yvette Cendes, (aka u/Andromeda321 on Reddit), a Radio Astronomer studying transient radio signals from space. As always, though, we start off with the day’s joyfully cool cosmic thing, a report by the Dark Energy Survey that seems to show that the amount of dark energy originally described as the cosmological constant by Albert Einstein might in fact be variable. As Prof. Cendes explains, the data indicates that universal expansion is still accelerating but the rate might be changing. After Yvette explains what she does, and how radio astronomy works in concert with optical astronomy to deliver a more complete understanding, Chuck asks her to explain Tidal Disruption Events, or TDEs, about which she’s a world expert. A TDE is when a star wanders too close to a supermassive black hole and ends up getting shredded. Yvette prefers to call them “Shredders.” Our first audience question comes from Nachama, who asks, “When will the black hole in the Milky Way eat the Sun?” The good news, according to Yvette, is that will never happen. As she explains, black holes actually don’t suck any more than anything that massive would, and we’re 25-30,000 light years away from Sagittarius A* – too far away to worry about. Next, Chuck asks Yvette about one of the most famous transient signals we’ve ever found, the so called “Wow!” signal detected in 1977 by Jerry Ehman at the now-defunct Xavier Observatory in Ohio. Because the signal looked exactly like what might be expected if it were of extraterrestrial origin, Ehman circled it on the printout and wrote, “Wow!” Unfortunately, it never repeated. The most likely explanation, according to Dr. Cendes, is that it was some sort of manmade interference, although the signal is currently being reinvestigated. Yvette recounts how she ended up ended up as a first-term professor at the University of Oregon after studying in the Netherlands and Toronto and working at Harvard. Then she answers an audience question from Yan Min, who asks, “Where is the best place in the world to study astronomy? I live in New York – Is it New York?” Unfortunately for Yankees fans, Yvette says it would most likely be Cambridge, Massachusetts thanks to Harvard, which has the biggest number of astronomers under one roof and operates the Chandra X-Ray Observatory, and M.I.T. on the other side of town if you get bored. Chuck asks Yvette what happens after a black hole shreds a star. Shredders, she explains, are rare. In our own Milky Way, they probably happen once every million years. Once a TDE is classified by optical astronomers, Yvette and her team point their radio telescopes at the tidal radius outside of the event horizon to discern the outflows weeks, months and even years after the initial event. He also asks Yvette if she has any hobbies to help her decompress from thinking about violent events in the universe. She likes to cross stitch, the “original pixel art.” Yvette shows us a cross stitch she made of the James Webb Space Telescope complex mirror, another featuring an 8-bit Mario screen with the words “What doesn’t kill me makes me smaller,” and a third with objects in the Solar System. She also embroiders and shows us a hoop featuring the constellations visible in the northern hemisphere night sky. We end with Yvette and Allen schooling Chuck about Reddit’s immense reach and value in scientific discourse. One subreddit, called r/Space, has “27 million intelligent lifeforms” subscribed to it. On Reddit, Yvette’s username is u/Andromeda321, and she’s one of the top users on the platform over 1 million karma points. She’s known for starting her posts that explain or comment on recent discoveries with the phrase, “Astronomer here!” If you’d like to follow Dr. Yvette Cendes, you can find her on Reddit, where she’s u/Andromeda321, and her dedicated subreddit, reddit.com/r/Andromeda321. You can also follow her on Bluesky @whereisyvette.bsky.social. Links to the astronomy cross stitch kits shown in the episode: Wonders of the Solar System cross stitch by Climbing Goat: https://www.climbinggoat.co.uk/products/wonders-of-the-solar-system  Constellation Series Star Map by Kiriki Press: https://kirikipress.com/products/star-map  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: Artist's conception of a tidal disruption event (TDE). – Credit: Sophia Dagnello, NRAO/AUI/NSF The Wow! signal represented as "6EQUJ5". – Credit: Big Ear Radio Observatory and North American AstroPhysical Observatory (NAAPO) Artist’s illustration of the material generated by a TDE or “Shredder” – Credit: X-ray: NASA/CXC/Queen’s Univ. Belfast/M. Nicholl et al.; Optical/IR: PanSTARRS, NSF/Legacy Survey/SDSS; Illustration: Soheb Mandhai #liuniverse #charlesliu #allenliu #sciencepodcast #astronomypodcast #yvettecendes #andromeda321 #astronomerhere #radioastronomer #transientradiosignals #darkenergysurvey #cosmologicalconstant #universalacceleration #wow!signal #6equj5 #tde #tidaldisruptionevents #supermassiveblackhole #shredders #sagittariusa #milkyway #crossstitch

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  48:24
• Early Galaxies, Intelligent Plants and the Geometry of D&D Dice With Justin Cole

  Why is it so difficult to study the evolution of early galaxies? Are metallic D&D dice better than plastic ones? And can you have too many Pokémon tattoos? To find out, Dr. Charles Liu and co-host Allen Liu welcome Justin Cole, who is currently a grad student at Texas A&M studying the evolution of distant galaxies in pursuit of his PhD in Astronomy and Astrophysics. As always, though, we start off with the day’s joyfully cool cosmic thing – the recent – and remarkable – discovery of four planets orbiting Barnard’s Star, a tiny star not much bigger than Jupiter with the highest measured proper motion of any star in our sky. Chuck and Justin discuss why the discovery of new exoplanets is so challenging, which leads to Justin explaining what he’s studying: galaxies in our universe that developed less than 1.5 billion years after the Big Bang – about 2.5 billion years before the birth of our own Milky Way Galaxy. We’ve got a handle on what’s going on with our neighbors like the Andromeda Galaxy, but when it comes to early galaxies, we have a very limited range of wavelengths and scant data to study. This makes it harder to derive understandings of galactic evolution and whether they support or conflict with the standard model of physics. Our first audience question comes from Ricardo, who asks, “What if we discover extraterrestrial plant life and find out it’s intelligent? Actually, what if we discover plants on Earth are intelligent? Would it be unethical to eat them?” After Chuck shares a little about Marvel’s intelligent, telepathic species of plants called the Cotati, and imitates Audrey 2 from Little Shop of Horrors, Justin weighs in on the ethics of eating intelligent plants and asks a critical question: Would we understand them enough to know? What would happen if we bit into a head of alien lettuce and it started screaming? The ensuing discussion is… tasty, albeit a little unsettling. Our next question is from Thomasina, who asks, “I read that the Big Bang theory is in trouble – what does that mean? And did the Big Bang never happen?” Justin, who is an early universe guy, clarifies what’s going on here. We occasionally find galaxies that seem to be too big for the amount of time that they’ve had to grow. We’re also finding black holes that with our current instruments, also appear to be too big. In each case, we’re finding better ways to simulate these situations, and it’s not that they’re too big, or that the Big Bang isn’t supportable, it’s that we’re using tools that are calibrated to “nearby and today” that aren’t as good at helping us assess early galaxies. Next up, Justin, who is getting ready to run a Dungeons & Dragons 5th Edition roleplaying session after the podcast recording, talks about using D&D Beyond to create his own campaigns (set in the World of Warcraft universe!). Chuck and Justin discuss the benefits of rolling metal dice, and Justin shows off a couple of his beautiful D20. Not to be outdone, Allen shares his 120-sided die, the largest die allowed by three dimensional Euclidean geometry in conventional space. Meanwhile, Chuck tells us the sad story of his old, worn plastic dice. As Allen points out, Chuck was in the hobby before it was cool! And as we run out of time, Justin shares his intention to get one Pokémon tattoo for every state he and his wife visit. If you’d like to know more about what Justin’s up to, he suggests you Google “Justin Cole Astronomy” or “Justin Cole A&M.” 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: Size comparison between Jupiter, Barnard's Star, and the Sun. – Credit: Creative Commons. Diagram of evolution of the (observable part) of the universe from the Big Bang (left), the CMB-reference afterglow, to the present. – Credit: NASA/WMAP Science Team. Evolution of the gas density overlaid with a transparency mask to only visualize regions with significant ionizing radiation in the Thesan-1 simulation. – Credit: Harvard-Smithsonian Center for Astrophysics. #TheLIUniverse #CharlesLiu #AllenLiu #SciencePodcast #AstronomyPodcast #JustinCole #Astronomy #Astrophysics #BarnardsStar #GalacticEvolution #BigBang #StandardModelofPhysics #ExtraterrestrialPlantLife #IntelligentLife #D&D #Pokemon #Tattoos

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  38:10
• Standing on the Edge of Discovery with Dr. Melodie Kao

  What’s it like to stand at the edge of human knowledge, where we don’t know what leap forward in understanding the next technological innovation will herald? To find out, Dr. Charles Liu and co-host Allen Liu welcome Dr. Melodie Kao, resident radio astronomer at the Lowell Observatory in Flagstaff, AZ, where Clyde Tombaugh discovered Pluto back in 1930. (And if you’re scratching your heads saying, “What’s a radio astronomer doing at an optical observatory?” you’re not alone. Short answer: Melodie convinced them they wanted one, and that it should be her!”) As always, though, we start off with the day’s joyfully cool cosmic thing, the amazing discovery by the NEID Spectrograph at the WIYN telescope at Kitt Peak Observatory of a planet 9 times the mass of Earth orbiting a sun-like star 49 light years away with an orbital period of just 31 days. Melodie explains the precision of the measurement required to discover a planet at that distance, and shares one of her own recent discoveries using a technique called very-long-baseline interferometry (VLBI). In a groundbreaking effort she strung together 39 radio dishes across the northern hemisphere of Earth in a multi-observatory effort to create an Earth-sized telescope (similar to the technique that was used to create the first image of a black hole) and pointed it at a brown dwarf and measured its magnetic fields and radiation belts (like our Van Allen belts). For comparison, the effort was like measuring a pea perched on the Golden Gate Bridge in San Francisco while standing on the Statue of Liberty in NYC. The trio discusses the importance of the discovery of the Van Allen belts, and how that allowed us to plot trajectories that avoided the worst of that radiation for Apollo astronauts on their journeys to the Moon. For our first audience question, Ari from North Greene High School in Tennessee asks, “What is the percentage of possible exoplanets that are similar to the earth’s atmosphere, placed in their solar system (within a similar area of their respective Goldilocks zone), gravity, etc.? And how long would it take to hypothetically get to them?” That turns out to be a very complicated question, and Melodie knows someone who has devoted her entire career to answering it. It’s one of the questions that drove the creation of the James Webb Space Telescope and is the basis of the Drake Equation. The bottom line, though, is that we don’t know yet, and until we find a rocky planet with an Earthlike atmosphere orbiting a sun-like star outside of our solar system, it will remain unanswerable. Next, Charles asks Melodie how she became an astronomer, especially since she’d always planned on being an architect. She even went to MIT to become one, but she missed studying physics, which she realized she truly loved. MIT had just finished constructing their Center for Theoretical Physics, and Melodie shares the story of how she convinced MIT to bend the rules and let switch her major to Physics while continuing to study architecture. When she attended a lecture by a grad student about galaxy clusters, and learned how you could back out the formation history of a cluster of galaxies by looking at the gradients of colors generated by starlight, she realized astronomy was a way to unlock the secrets of the universe. Our next question comes from Alex at North Greene: What are the conditions necessary for life in the universe? It’s a question without an easy answer, but the conversation it spawns is worth your time to listen to. It leads Melodie to talk about her love of exploring the natural world and how she co-created a Wilderness Astronomy class. She’s also a guide for off-trail, high route backpacking trips where you don’t know what’s coming next and you need to rely on your instincts, curiosity and bravery as you explore the world, and the universe, around you. If you’d like to know more about what Melodie is up to, she’s not on social media but you can check out her website. You’ve also got an invitation to visit her at the Lowell Observatory for a personal tour! 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: Dome of the 3.5m WIYN telescope at Kitt Peak – Credit Jörg Weingrill/ Creative Commons A cross section of Van Allen radiation belts – Credit By Booyabazooka at English Wikipedia - Transferred from en.wikipedia to Creative Commons / Public Domain The NASA Very Long Baseline Interferometry (VLBI) network – Credit Creative Commons / C. García-Miró, I. Sotuela, C.S. Jacobs, J.E. Clark, C.J. Naudet, L. A. White, R. Madde, M. Mercolino, D. Pazos, G. Bourda, P. Charlot, S. Horiuchi, P. Pope, L.G. Snedeker MIT Center for Theoretical Physics – Credit MIT News Galaxy cluster IDCS J1426. – Credit NASA The Cirque of the Towers, popular with high route backpackers. – Credit Kylir Horton / Creative Commons

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  43:43
• Future Fashion: Spacesuits, Exoskeletons & More with Alexia Stylianou

  What will well-dressed astronauts be wearing on the Artemis III mission? Will AI destroy creativity? Can we actually make leather clothing out of mushrooms? To find out, Dr. Charles Liu and co-host Allen Liu welcome engineer and futurist Alexia Stylianou, who is designing wearable biometric platforms that can measure human biomechanics to a resolution and degree far beyond what’s accessible to everyday people. Before we get to introducing our guest this episode, though, Charles whets our appetite about amazing developments coming out of the Vera C. Rubin Observatory where he’s on the Science Advisory Committee. Our joyfully cool cosmic thing of the day is Firefly Aerospace’s Blue Ghost Mission 1 to the Moon. As Allen points out, it’s part of NASA’s CLPS (Commercial Lunar Payload Services) initiative and is the most successful private Lunar landing to date – among other things, it landed right-side up! Alexa talks about the importance of giving engineers the freedom to solve problems and the uncertainty of programs like this continuing to be funded by NASA. Allen brings up the Viper, a NASA-funded lunar rover which was built, but lost its funding before testing was completed. Charles asks Alexia to tell us about an example of something on the horizon she thinks is really cool, and she mentions that Prada is designing the space suits for the Artemis III mission in partnership with Axiom Space. She explains that Prada has a history of using cutting edge materials and design that makes them an appropriate partner in the process. Then it’s time for our first audience question. Luis asks, “What is needed to create the next amazing space technology that will break all the conventions we have about space travel?” Alexia talks about the increasing importance of incorporating user-centered design or human-centered design, and how it’s revolutionizing the process. You’ll hear about the development of direct pressure space suits, as well as research into exoskeletons for use in industry and auto manufacturing – although sadly, Alien-style exoskeleton loaders like Ripley uses are still science fiction, for now. Looking even further out, Alexia talks about nuclear semiotics – the effort to come up with ways to communicate to societies that will exist hundreds of thousands of years in the future the danger of radioactive material we’re creating now? You’ll find out why the skulls and crossbones and other danger iconography we use now aren’t up to the task, and the universality of stick-figure iconography. Our next question comes from Johanna: “Will AI destroy creativity?” Questions like this are becoming more frequent, especially in areas like education. Chuck, Alexia and Allen jump into a thought-provoking conversation, and how there are ways to let students use AI as a tool like a calculator while simultaneously incentivizing and stimulating their creativity. Speaking of creativity, Chuck asks Alexia about her love of science fiction and the well-designed stack of books behind her (sorry, Podcast People!). She pulls out and describes “Gideon the Ninth,” the first book in a sci-fi fantasy series about immortal space necromancers by Tamsyn Muir. Alexia talks about speculative fiction and speculative design, and tells us about a team of designers that have created a room that smells like the pollution of the future in order to offer a tangible way to engage our senses now about a future we might yet be able to avoid. Finally, Chuck asks Alexia for one more cool futuristic development she’s wants us all to think about. She tells us about the development of mushroom leather (aka mycelium leather), an alternative, eco-friendly, and ethical textile made from fungi grown on apple waste. If you’d like to know more about Alexia, you can find her on LinkedIn. 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: NSF-DOE Vera C. Rubin Observatory on Cerro Pachón in Chile. – Credit: NSF-DOE Rubin Observatory/AURA/B. Quint. Blue Ghost final descent and landing video. – Credit: NASA/Olivia Tyrrell. Prada and Axiom Space Extravehicular Mobility Unit (AxEMU). – Credit: Prada/Axiom Space (image provided for press coverage). The Space Activity Suit developed by Paul Webb and built under a NASA project (taken c. 1971). – Credit: NASA. Exoskeleton designed for the auto industry by Ekso Bionics. – Credit: Ekso Bionics. Proposed design for "small subsurface markers" to be buried randomly in great numbers across the Waste Isolation Pilot Plant. – Credit: Department of Energy (Public Domain).

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  47:01
• Half-Baked Stars and Handmade Macarons with Dr. Theron Carmichael

  What is a transiting brown dwarf, why are they so rare, and how do you find them? Equally important, how do you make a good French macaron? To find out, Dr. Charles Liu and co-host Allen Liu welcome astronomer and astrophysicist Dr. Theron Carmichael. As always, though, we start off with the day’s joyfully cool cosmic thing: a recent paper in the Astrophysical Journal possibly linking a supernova that took place millions of years ago and bombarded Earth with cosmic rays and radioactive iron with a flurry of virus mutation that took place in deep ancient lakes on our planet. After Theron brings up the Chicxulub meteor impact (the one that spelled trouble for dinosaurs) and how astronomical events can affect the evolution of life here on Earth, we naturally turn to the effects of extreme radiation events and… the mighty Marvel mutants themselves, the X-Men! Then it’s time to talk about Dr. Carmichael’s bread and butter: detecting and categorizing transiting brown dwarfs, an exceedingly rare form of the “failed stars” which actually orbit other stars. Theron explains that while we know how stars and planets form, we don’t exactly understand the formation of brown dwarfs, which exist in the gray region between a star and a planet. Allen reminds us how protoplanetary discs form, while Theron points out that the distinctions may not be as clear as we used to think. Our first student question comes from Ani, who asks, “There are a lot more small, faint stars than big bright stars. Does that mean there are a huge number of brown dwarfs in the galaxy?” Yes, according to Dr. Carmichael. And not only are there more of them, but Theron explains that they last longer, too. Finding them is challenging, but it’s become easier thanks to TESS, the Transiting Exoplanet Survey Satellite mission that’s been running for over 7 years, well past its operational lifespan. Our next student question comes from Josie, who asks, “Could there be life on brown dwarfs?” While brown dwarfs are colder than stars, they are still too hot to form and sustain the molecules we believe are necessary for life. And while those molecules are in fact present in the atmosphere of brown dwarfs – along with titanium oxide clouds – the pressure and temperature conditions of brown dwarfs make life as we know it unlikely. Theron explains that the atmospheric conditions of brown dwarfs are not dissimilar to Jupiter, as opposed to those on Jovian moons like Europa that we’re going to explore when the Europa Clipper reaches its destination in 2030. After that, Theron tells us about the annual MIT Mystery Hunt, his long-time love of baking, and the astronomical value of macarons. (For his French macaron recipe, please visit our Patreon page.) Allen shares how he has made cookies conforming to the Einstein tile, and Charles mentions a few scientists who also love to bake. Theron explains how baking and brown dwarf research use the same parts of his brain. We even get to see a video clip of him making macarons! To end the show, Theron tells us about the international working group he helps lead focused on learning more about transiting brown dwarfs. If you’d like to know more about Dr. Theron Carmichael, you can follow him on Twitter/X @TherBaer or his website, www.theroncarmichael.com. 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: Chicxulub impact 65 million years ago – Illustration credit: Lunar Planetary Institute/David King. Rendering representing the size of a Brown Dwarf compared to other celestials. – Illustration credit: NASA/ JPL-Caltech/ UCB. Planets forming around a young star – a protoplanetary disc. – Credit: NRAO/AUI/NSF. Illustration of the Transiting Exoplanet Survey Satellite (TESS) mission. – Credit: NASA. Rendering of Europa Clipper as it orbits Jupiter. – Credit: NASA/JPL-Caltech. Animation showing the orbit of the TESS telescope relative to the Earth and the Moon. – Credit: NASA Scientific Visualization Studio. Einstein Tile - a play on the German phrase "ein stein' or "one stone." – Credit: Creative Commons/University of Waterloo/David Smith, Joseph Samuel Myers, Craig S. Kaplan, Chaim Goodman-Strauss. Video of Dr. Carmichael making macarons. – Credit: Theron Carmichael. #TheLIUniverse #CharlesLiu #AllenLiu #SciencePodcast #AstronomyPodcast #TheronCarmichael #Chicxulubmeteor #BrownDwarf #protoplanetarydisc #TESS #EuropaClipper #exoplanets #EinsteinTile #macaron #failedstars #Jupiter #Europa #MITMysteryHunt

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  37:22

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