The LIUniverse with Dr. Charles Liu

It’s time for the Season 5 finale of The LIUniverse, which means another episode of ChuckGPT where we answer our audience’s most vexing questions – this time via video from our Patreon Patrons. And to help us answer those questions, Dr. Charles Liu and co-host Allen Liu welcome back fan favorite guest and expert on ancient civilizations, author and educator Hannah Liu, M.Ed.

As always, though, we start off with the day’s joyfully cool cosmic thing: the completion of DESI’s 5-year survey mapping millions of objects in the universe. The Dark Energy Spectroscopic Instrument completed the survey ahead of schedule, so there’s still time to map millions more.

Hannah tells us about mapping the universe in antiquity, starting with the first star catalog created by the Babylonians about 3,000 years ago. You’ll hear about the Venus tablet from the first millennium BC, Chinese star charts from the Tang dynasty, and Atlas, the mythological Titan who was the “first astrologer.”

Returning to the DESI survey, Chuck talks about the change in the dark energy content of the universe that we didn’t really expect. Allen, our resident mathematician, talks about the velocity of universal expansion and a concept called “the jerk.”

Then it’s time for audience questions, and for this episode, we’re doing something new. Both audience questions come from Patreon Patrons, and both are in video format so you can actually see our fans asking Chuck the questions – if you’re watching rather than listening, that is.

Our first question comes from Patron Lee Dubey, who asks, “Since atoms are mostly empty space, could all matter, including measuring devices, almost undetectably consume minimal space, warping the space around it? If so, could that cause gravity, and could the shrinkage cause a redshift related to dark energy?”

We’re not even going to try and summarize the explanation from Allen and Chuck here, except to say that the ensuing conversation includes the physics concept of “unparticles.” Hannah brings up Democritus, who, along with his teacher Leucippus in ancient Greece, first theorized the existence of atoms.

Our next question comes from our Patreon Patron Lee Williams, who asks, “If we live in a simulation, is it correct to assume that there’s an architect? Could there be a simulation without an architect?”

Given that there’s no scientific answer to either of these questions, Chuck turns to Hannah for enlightenment. While she explains that the question of whether we live in a simulation is a modern concept, Hanna discusses how humanity grapples with the questions of existence and higher powers, and why people engage with religion, magic, or quantum entanglement in the first place.

In the free-wheeling, far-ranging conversation that follows, Allen brings up how we create simulations now, by creating processes and letting them run, to offer some perspective on the role of the architect. And yes, H.P. Lovecraft, “The Devil and Daniel Webster,” “Frankenstein: The Modern Prometheus,” and even Spider-Man somehow make it into the discussion.

And that’s it for this season of The LIUniverse. We want to thank all of you for your questions, your curiosity, and your help in keeping this experiment going. As Chuck always says, “Thank you for being a part of The LIUniverse.”

We hope you enjoyed this episode, and this season, of The LIUniverse. If you do, please support us on Patreon.

Credits for Images Used in this Episode:

Map of DESI’s 5-year survey. – Credit: Claire Lamman/DESI collaboration.

Roman statue of Atlas (2nd century AD). Credit: Lalupa / Creative Commons

The Venus tablet recording astronomical positions for Venus dating from the first millennium BC. – Credit: FAI / Creative Commons

Chinese Tang dynasty star map made around the year 700. – Credit: Public Domain.

 

CHAPTERS

00:00 - We Welcome Back Archaeology Expert, Author and Educator Hannah Liu, M.Ed.

02:28 - Joyfully Cool Cosmic Thing: DESI Completes Its 5-Year Survey of the Universe

04:33 - Mapping the Universe in Antiquity

12:06 - The Empty Space in Atoms, Gravity, Shrinkage, and Dark Energy

16:42 - What Are Unparticles?

22:53 - Do We Live in a Simulation? Is There an Architect?

How do distant galaxies form? If you have two distant clouds of hydrogen, why does one turn into a star and another doesn’t? To find out, Dr. Charles Liu and co-host Allen Liu welcome Dr. Erika Hamden, Professor of Astrophysics at the University of Arizona. If Erika looks familiar, that might be because her TED Talk or “New Frontiers,” the TV show she hosts on Arizona Public Media.

As always, though, we start off with the day’s joyfully cool cosmic thing, Artemis II, our first manned mission around the moon since 1972. Chuck, Allen and Erika share their excitement watching the mission, and especially the landing, while we watch the “only good video of the moon ever taken with a phone” that Reid Wiseman shot on his iPhone.

Dr. Hamden tells us about her research into how distant stars and galaxies form. To fill in the blanks of this cosmic puzzle, she observes hydrogen in its elemental or molecular form – not looking at the stars themselves, but the emissions from hydrogen atoms. You’ll learn about star formation in our galaxy and how Erika discerns the moment that a new star “first turns on.”

Then it’s time for our first audience question. Emma B. asks, “How many galaxies are there?” Erika says that in the observable universe, it’s an outrageously large number, probably hundreds of billions or more. We take a look at the Hubble Ultra Deep Field image, which reflects a “tiny, tiny part of the sky,” where every dot except for the 3 stars is a galaxy. And that’s just the universe we can see.

Chuck asks Erika to tell us about her book, “Weird Universe: Everything We Don’t Know about Space (and why it’s important).” Professor Hamden shares her belief that anyone can understand anything if it’s explained the right way to them. She talks about a poem by Rebecca Elson called “Responsibility to Awe” and the responsibility scientists have to share the wonders of the world with everybody.

For our next audience question, Ava asks, “What is the craziest job in Astronomy that you have seen AI take over from humans?” Erika talks about using LLMs to review the digitized photographic plates of stars and the massive amount of data from the Vera Rubin Observatory, and also which activities still require human creativity.

Speaking of creativity, it turns out that before becoming an astrophysicist, Erika got a diploma at Le Cordon Bleu in London and had a career as a professional chef. She still loves to cook and shares her recipe (below) for the Swedish-style cardamom buns she shows us in the episode.

Finally, before we go, we congratulate Emily on recently being awarded a Guggenheim Fellowship. She shares some wisdom and advice she’s learned on her journey that she also tells her students, but according to her it’s a bit “cheesy” so we’ll let her tell you in the show.

If you’d like to know more about Dr. Hamden, you can keep up with her research, follow her on her social media accounts, and find out about her book by visiting her website.

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

 

Erika’s Cardamom Bun Recipe

You can find the original recipe here on Cecilia Tolone’s Substack.

Erika’s Modifications:

“My changes are that I add more milk- about 75 grams more, because American flour is drier and Tucson is especially dry! And I played around with adding chiltipin flakes (a local, very spicy pepper) to the filling to make it kind of spicy. It’s great! Finally, I use whole cardamom seeds from Penzey’s that I grind before putting in.”

 

Credits for Images Used in this Episode:

Artemis II end of mission splashdown. – Credit: NASA/ Bill Ingalls.

Artemis II astronaut Reid Wiseman’s iPhone video of the Earth and the Moon with his iPhone 17 ProMax, using 8x zoom, which he said is comparable to what he was seeing from the Artemis II capsule. – Credit: NASA /Reid Wiseman

Hydrogen observed in the Milky Way Galaxy. – Credit: HI4PI Collaboration

The Hubble Ultra Deep Field. – Credit: NASA/ESA

Example of a photographic plate of stars, including notation marks, aka a Schmidt ammonia-sensitized, near-IR (Kodak I-N) objective-prism plate exposed for 1 hr. – Credit: STScI/ESO/Carnegie.

 

Additional Credits:

A Responsibility to Awe, by Rebecca Elson

 

CHAPTERS

00:00 - We welcome University of Arizona Astrophysics Prof. Dr. Erika Hamden

02:43 - Joyfully Cool Cosmic Thing: Artemis II Mission and Return

08:14 - How Do Distant Stars and Galaxies Form?

15:46 -How Many Galaxies Are There?

18:25 - Weird Universe and Scientists’ Responsibility to Awe

24:06 - What Jobs in Astronomy Has AI Taken Over from Humans?

31:33 - Chef Erika and her Swedish-style Cardamom Buns

39:10 - Parting Advice and Wisdom from Professor Erika Hamden

 

#LIUniverse #CharlesLiu #AstronomyPodcast #ErikaHamden #GalaxyFormation

Are there really exoplanets with where it rains ruby and emerald raindrops? How do we measure the atmospheres of exoplanets light years away?

To find out, Dr. Charles Liu and co-host Allen Liu welcome Dr. Munazza Alam of the Space Telescope Science Institute. The STScI performs science operations for the Hubble Space Telescope, the James Webb Space Telescope, and the Nancy Grace Roman Space Telescope when it launches in 2026.

As always, though, we start off with the day’s joyfully cool cosmic thing. On Feb 24, 2026, the Vera C. Rubin Observatory activated the alert system it will use to notify astronomers of noteworthy events and sent out 800,000 alerts on that single day!

Munazza tells us about how she studies the atmospheres of exoplanets like Wasp 121-b, a gas giant thought to have ruby and sapphire rain. Dr. Alam describes exoplanets with surface oceans made of magma, and she and Chuck talk about the importance of plate tectonics.

You’ll hear about Hot Jupiters, Super-Earths, and Sub-Neptunes – and the theories about why we don’t have any of them in our solar system despite the fact that they’re incredibly common in the Milky Way galaxy.

Then it’s time for audience questions, which for this episode come from students at Notre Dame Academy on Staten Island, where Munazza is an alum. Not only does past guest Dr. Betty Jensen teach there, as well, but she was a critical influence on Munazza’s career path. (You can listen to our episode with Dr. Jensen here.)

The first question is from Charlotte, who asks, “How far have we gone in space?” Munazza, Allen, and Chuck discuss Voyager 1, which at a current distance of nearly 16 billion miles is the man-made object that has gone furthest from Earth.

Next up, Gabby asks, “What was the best advice you were given when you were preparing for college?” Dr. Alam’s answer: Pick something you enjoy and are good at - in spite of any pressure you might get from friends, family, and others.

A second piece of advice Munazza got was to maintain your breadth, i.e., developing other interests besides your primary focus. For Munazza, that was art and writing, and she shares some of her art later in the show.

Finally, Gisella asks if it was hard picking a college. Dr. Alam shares her process, with the caveat that it might not be good advice for everyone.

Charles and Munazza reflect on the tradition of scientific exploration, observation, discovery and analysis of which she’s part. Munazza recounts the excitement when JWST observations of transmission spectra of the exoplanet Wasp 39b confirmed their predictions – and also detected something unexpected: sulfur dioxide in the atmosphere of the planet which is a by-product of photochemistry between light from its star and water molecules in the atmosphere of the planet.

Finally, Chuck asks Munazza to share some of her art. She shows us one of the first paintings she ever did, a peacock, and tells us a little about it and a portrait she has displayed at the Lowell Observatory.

If you’d like to know more about what Dr. Alam is up to, you can follower her on LinkedIn or visit 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:

Artist impression of Wasp 121-b, an exoplanet thought to have ruby and sapphire rain. – Credit: NASA, ESA, Q. Changeat et al., M. Zamani (ESA/Hubble)

Quake epicenters Digital Tectonic Activity Map of the Earth (DTAM). – Credit: NASA/Goddard Space Flight Center

Illustration comparing the sizes of sub-Neptune exoplanets TOI-421 b and GJ 1214 b to Earth and Neptune. – Credit: NASA, ESA, CSA, Dani Player (STScI)

Illustration of the inferred size of the super-Earth CoRoT-7b (center) in comparison with Earth and Neptune. – Credit: Creative Commons / Aldaron

Location of the Voyager 1 and Voyager 2 spacecraft. – Credit: NASA/JPL-Caltech

JWST transmission spectra of the exoplanet Wasp 39b. – Credit: NASA, ESA, CSA, Joseph Olmsted (STScI)

Radial velocity method to detect exoplanets. – Credit::ESA

Transit method for discovering exoplanets (animation). – Credit: NASA PlanetQuest

Artist's concept of WASP-107b, a gas giant, orbiting a highly active K-type star about 200 light-years from Earth. – Credit: ESA/Hubble, NASA, M. Kornmesser

 

CHAPTERS

00:00 - We welcome Dr. Munazza Alam of the Space Telescope Science Institute

02:50 - Joyfully cool cosmic thing: Vera C. Rubin Observatory Alert System

07:00 - How Do We Know What Exoplanets Are Like?

10:37 - The Importance of Plate Tectonics

11:45 - Hot Jupiters, Super Earths, and Sub-Neptunes

19:56 - How Far Have We Gone In Space, i.e., Where is Voyager now?

22:44 - Best advice when preparing for college?

25:32 - Was it hard picking a college?

31:00 - Confirming Theories and Discovering the Unexpected

36:33 - Munazza Alam Shares Her Painting of a Peacock

38:49 - What data and measurements are used to study exoplanets?

Can the physics you learned in High School take you to the stars? Who is behind many of your favorite pictures of space? What is it actually like to live and work in space? You might be surprised to know how much of it comes down to the physics you probably learned in class and thought to yourself, “When will this ever be useful?”

To answer those questions and more, Dr. Charles Liu and co-host Allen Liu welcome Dr. Don Pettit –NASA astronaut, astrophotographer, chemical engineer, and genuinely one of the most interesting people alive, who was also a science consultant for the movie Project Hail Mary. As you’ll see, the complex physics of space could be critical to your future endeavors in the world of tech, space, and astrophysics.

As always, though, we start off with the day’s joyfully cool cosmic thing, which was the famous DART mission (Double Asteroid Redirection Test). It’s a mission where NASA crashed a spacecraft into a small asteroid (Dimorphos) to see if they could literally change the orbit of an asteroid in space. This mission was successful, changing the asteroid’s orbit by nearly 30 mins. This is certainly joyfully cool, as it shows we can take planetary defense measures to change the path of an impending asteroid.

Throughout the episode, Don, Chuck, and Allen ping pong back and forth with the following topics:

Why he chose chemical engineering (and how that led to becoming an astronaut by consistently choosing passion and innovation over money)

Whether being an astronaut is even worth it financially

How cities look different from orbit over time (yes, you can literally see lighting technology evolve)

The physics behind astrophotography from space (and why those images look so insane)

How astronauts drink coffee in zero gravity!

Just wait, there is even more that we dive into: from lunar bases, to Antarctica meteorite hunts, to a casual mention of driving a lunar rover simulator like it’s nothing.

There’s a lot here that feels huge and abstract, but also weirdly human, like choosing passion over money, or just wanting your morning espresso in space. While Don always had a love for chemistry, he ultimately pursued chemical engineering because he thought he wouldn't be able to get a good job without higher ed (relatable or what?). Then he got a PhD anyway, following his passion.

Don also discusses the coffee cup he invented, which is widely used in space and lets you drink espresso like normal. He designed a cup that lets astronauts drink normally in zero gravity using fluid physics.

Toward the end of the episode, he talks about going to Antarctica to collect meteorites and what that tells us about the chemistry of space.

During this episode, Don’s intrinsic love for creation and scientific innovation shines through. If you like physics, space, or just hearing someone explain complicated things in a way that actually makes sense, you’ll absolutely love this.

If you want to know more about Dr. Don Pettit, you can find him on NASA’s website. For the latest updates on his many projects and dazzling astrophotography, check out his Instagram @astro_pettit. (We’ve included some of those photos in the episode - just another reason to watch on YouTube!)

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:

Photo of asteroids Didymos and Dimorphus, NASA’s DART mission target. Credit: NASA/Johns Hopkins APL

Lunar map depicting craters on the south pole of the Moon. Credit: USGS

Don Pettit taking photos on the International Space Station. Credit: NASA

Chicago as seen from the ISS. Credit: NASA/Don Pettit

Burj Khalifa, the world’s tallest building, as seen from the ISS. Credit: NASA/Don Pettit

Sao Paulo, Brazil, at Night, April 12, 2003 as seen from the ISS. Credit: NASA/Don Pettit

Star trail time exposure, taken for approximately 30 minutes during orbital night, assembled from multiple 30 second exposures. Credit: NASA/Don Pettit/Babak Tafreshi

The first prototype of Don Pettit’s capillary cup. Credit :NASA

Astronaut Samantha Cristoforetti drinking from Don Pettit’s cup on the ISS. Credit: NASA

ANSMET meteorite hunters in Antarctica. Credit: NASA

Cross-section of a carbonaceous chondrite, the 4.5-billion-year-old Allende meteorite formed along with the solar system. Credit: AMNH/Creative Commons

Spaceborne - Don Pettit’s photography book. Credit: Don Pettit / Press Syndication Group

 

Special thanks to Eleanor Adams for writing this episode description.

 

 

CHAPTERS

0:00 - Introduction of Astronaut Don Pettit

3:19 - Asteroid Defense Explained (DART Mission & Saving Earth)

10:49 - Don Pettit’s Early Life

14:50 - How Much Does It Pay to Be an Astronaut?

17:11 - What It’s Really Like Living in Space for Months

19:49 - Physics Behind Astrophotography: LEDs and Light Pollution

30:00 - Space Coffee Cup Invention

41:00 - Astrochemistry and Antarctica

How do we find exoplanets? What is the Milky Way’s “Thick Disk” and what makes it so special? To find out, Dr. Charles Liu and co-host Allen Liu welcome Harvard astronomer Dr. Victoria DiTomasso, who has discovered an exoplanet system that includes exoplanet HD60079 b, which she sometimes calls “Bubbles.”

As always, though, we start off with the day’s joyfully cool cosmic thing, a paper just recently published about the exoplanet Teegarden Star b. Dr. DiTomasso explains the difference in exoplanet research between the observational studies she does and the theoretical modeling represented in the paper.

She goes on to discuss recent, exciting theoretical work coming out of UCLA that posits that rather than have our water brought to Earth by comets, we started out as a larger, sub-Neptune planet with a larger hydrogen-helium envelope that we’ve lost over time. This is a pattern seen in some exoplanets, especially given the fact that Super Earth and sub-Neptune planets are the most common types of planets we’ve found, yet we have none in our solar system.

After we find out why a planet Chuck studied was called Flagellan, it’s time to find out how Victoria goes looking for exoplanets, and how she found Bubbles – with an assist from a team of citizen scientists. You’ll learn about using the transit method for discovering exoplanets and identifying potential targets with TESS, the Transiting Exoplanets Survey Satellite and other instruments.

Dr. DiTomasso explains the differences between the Milky Way’s younger “Thin Disk,” the older “Thick Disk,” and the oldest of all, the Milky Way’s “Halo.” Victoria studies the chemistry of stars to categorize them and their planets by age. She’s found 4 stars in the thick disk that have “Hot Jupiters” so far, which is more impressive when you learn that we only knew about one before her work.

Then it’s time for a question from the audience. Grace asks, “Has the environment ever been as bad as it is now, and can it heal by itself?” Chuck, Allen and Victoria discuss changing environments on exoplanets and on Earth, the difference between long and short term change, and the possibility of recovery.

Finally, Chuck asks Victoria what she does outside of astronomy, and we learn all about her new hobby, crocheting. Don’t miss her show and tell, which includes Fred, the cutest crocheted dinosaur to ever appear on The LIUniverse. Victoria also talks about her other hobby, visiting museums – especially art museums. If you’re watching this episode on YouTube, you get to see one of her current favorite exhibits, which consists of semi-abstracted felted wool sculptures of creatures and supernatural beings (yōkai) at the MassArt Museum (MAAM) in Boston.

If you’d like to know more about Dr. Victoria DiTomasso, you can find her on LinkedIn . But to see her latest telescope photos that she took during her observing trip to the Canary Islands, check out her Instagram @victoriaditomasso. (We’ve included some of those photos in the episode - just another reason to watch on YouTube!)

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:

Radial velocity measurements graphic depicting the Radial velocity method to detect exoplanets. – Credit: ESA.

Artist concept of the exoplanet Teegarden's Star b, also known as Teegarden b. – Creative Commons/ Bubblesong.

Illustration comparing sizes of sub-Neptune exoplanets with Earth and Neptune. – Credit: NASA, ESA, CSA, Dani Player (STScI).

Transit method for discovering exoplanets (animation). – Credit: NASA PlanetQuest.

All-sky image showing the flat plane of the Milky Way galaxy. – Credit: E. L. Wright/UCLA, The COBE Project, DIRBE, NASA.

Illustration of the Milky Way’s halo. – Credit: Halo stars: ESA/Gaia/DPAC, T Donlon et al. 2024; Background Milky Way and Magellanic Clouds: Stefan Payne-Wardenaar.

Masako Miki's "Midnight March" features semi-abstracted felted wool sculptures of creatures and supernatural beings (yōkai) at the MassArt Museum (MAAM) in Boston. – Credit: Masako Miki/MAAM

Photos from Victoria DiTomasso’s observing trip to the Canary Islands. – Credit: @victoriaditomasso on Instagram.

 

CHAPTERS

00:00 - Intro and Let’s Meet Dr. Victoria DiTomasso

03:53 - Joyfully Cool Cosmic Thing of the Day: Exoplanet Teegarden Star B

06:20 - Super Earth and Sub-Neptune Exoplanets

12:46 - The Discovery and Naming of Bubbles the Exoplanet

20:32 - The Difference Between Milky Way’s Thin Disk, Thick Disk, and Halo

27:58 - Audience Question: Has the Environment Ever Been this Bad?

36:51 - Crocheted Dinosaurs and Giant Felt Museum Creatures

45:14 - Victoria DiTomasso’s Observing Trip to the Canary Islands

 

#LIUniverse #CharlesLiu #AstronomyPodcast #VictoriaDiTomasso #Exoplanets