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Explore every episode of the podcast Walkabout the Galaxy

Dive into the complete episode list for Walkabout the Galaxy. Each episode is cataloged with detailed descriptions, making it easy to find and explore specific topics. Keep track of all episodes from your favorite podcast and never miss a moment of insightful content.

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TitlePub. DateDuration
Ocean World Mimas and the JUICE Slingshot28 Aug 202400:46:01

Recent (astronomically speaking, of course!) perturbations to Mimas's orbit may be the explanation for the surprising presence of a global subsurface ocean in this tiny moon of Saturn. Meanwhile, the European Space Agency's JUICE (Jupiter Icy Moon Explorer) mission successfully completed a novel gravity assist making use of the Earth's Moon and the Earth to send it towards... Venus! We have all the explanations, space travel stumpers, trivia and more.

Barney the Dinosaur Killer from Outer Space and Water Inside Mars21 Aug 202400:40:24

New research shows that the asteroid that killed the dinosaurs some 66 million years ago formed in the colder, more distant reaches of the solar system. The Astroquarks have taken it upon themselves to dub this asteroid Barney. We'll update you on that new research and a surprising discovery from Mars Insight data that suggests Mars has a potentially huge amount of delicious H2O not to far beneath its surface. It's just a bit dirty, is all. And we have lots of space news, stumpers, and more. Join us, won't you?

 

Watery Erigone and Rogue Stars in the Milky Way30 May 202400:45:18

New observations of Erigone, the parent body of an asteroid family, indicate its rocks are juicy with water. That makes it both a potential resource for future missions but also shows that asteroids may have played a big role in delivering water to the early Earth. Watery Erigone: it rhymes! You'll have to listen for details. And students discovered three high-speed wayward stars in the Milky Way, relics from an ancient galactic collision. Join us for all this, space news, trivia, fake sponsors, and more.

Dyson Spheres and a Molten Planet15 May 202400:42:39

The Astroquarks delve into the possibility of giant alien constructs around stars, and the strange weather on a planet that is unreasonably close to its star. Join us for space news, trivia, and a fun exploration of odd topics in astronomy on Walkabout the Galaxy.

The Low Down on Big G and the Young Moon of Dinkinesh08 May 202400:45:19

NASA's Lucy mission discovered a surprising moon of the small asteroid Dinkinesh on its way to the orbit of Jupiter. New studies of that moon, a contact binary, suggest it may have a surprisingly young age. Meanwhile, cosmologists continue to wrestle with various seemingly contradictory measurements. One model suggests a modification to that old Physics 1 standby, the gravitational constant (or is it?) G. Join us for all the astronomical news near and far, including space news updates and trivia.

Dark Matter Wins Again01 May 202400:45:48

A clever test of dark matter and an alternative theory of gravity to explain the motions of stars around galaxies results in another check in the win column for dark matter. Simulations with the modified model of gravity failed to explain the motions in the inner regions of galaxies. Meanwhile the search for a hypothesized large object in the distant reaches of our solar system has so far come up empty suggesting that it may be larger and more distant than previously thought. Join us for all the intriguing and exciting space news in the universe!

Surprises from Bennu and the Milky Way03 Apr 202400:41:16

Analysis of the samples returned from the asteroid Bennu have revealed surprising assemblages of minerals that put new constraints on the origin of the solar system. And once Top Quark Jim Cooney stops giggling, he tells us about the discovery of an itsy-bitsy galaxy, if you can call it that, orbiting the Milky way. It has only dozens of stars, plus, probably some dark matter. Join us for these surprising discoveries, space news updates, variable star trivia, and a generally good time.

The Dark Ages of the Universe27 Mar 202400:41:54

We peer back in time both to the murky history of our own solar system and to the dark ages of the universe. The JWST has confirmed that dwarf galaxies were the first to illuminate the universe, putting an end to the dark ages that followed the cooling after the big bang. In our own corner of the universe, new research highlights how nearby stars can lead to dramatic changes in our planet's climate by affecting the Earth's orbit. Join us for all this, nerd news, space news, and eclipse trivia.

A Nova Visible this Year?20 Mar 202400:39:49

One of only a handful of recurrent novas, white dwarf stars that undergo a periodic explosive brightening as they accrete material from a neighboring star, is showing signs that it may be ready to blow sometime in 2024! Visible in the northern hemisphere, T CrB may become visible to the naked eye for a few days this year, repeating a cycle that occurs roughly every 80 years. Closer to home, new analysis of structures and composition on Mars' Tharsis bulge reveal what may be a previously unknown and now-extinct volcano. Join us for explanations, space news, spaceflight trivia and more.

Psyche Revisited and Two Giant Black Holes06 Mar 202400:44:35

The presumed metallic asteroid Psyche gets a new look before the spacecraft of the same name gets there in 2029, and it reveals different spectral characteristics than were observed in previous studies. We discuss the mystery of metallic asteroids and what we might see at Psyche. Top quark educates us about the largest binary black hole system, with two supermassive black holes orbiting each other from an ancient galactic collision. Join us for all this, space news, and tiny rocket trivia.

 

The Tiniest Ocean World and the Brightest Quasar28 Feb 202400:45:36

Saturn's so-called Death Star moon Mimas may harbor a global subsurface ocean based on analysis of Cassini data of the tiny moon's orbit and rotation. And in the distant universe, what was previously thought to be a run-of-the-mill star in our own galaxy turns out to be a quasar thousands of times brighter than our entire galaxy itself. Join us on our 350th episode for breakthroughs in astronomy near and far, space news, sci-fi trivia, and more.

Space Oddities in the Solar System21 Feb 202400:41:09

Water molecules have been observed on the surface of an asteroid for the first time, and new studies help explain some of the odd behavior of planetary ring systems, including why they even exist around small objects in the outer solar system. Join us for a clear and fun explanation, the latest from Mars, upcoming missions, space trivia and more.

The Fermi Paradox - Are We Truly Alone?14 Aug 202400:41:00

When Frank Drake created his famous eponymous equation to estimate the number of advanced communicative civilizations in the Milky Way, we had little more than educated guesses for most of the factors in that equation. Decades later we have much better data, and the answer seems to reinforce Fermi's famous paradox: why is our galaxy so silent? The role of plate tectonics in enabling evolution of advanced life forms is examined in new research were a revision to the Drake Equation is proposed, and the unsettling answer may be that we are truly alone.

When Will We Walk on Mars?07 Feb 202400:41:41

In this special episode recorded live at MegaCon Orlando 2024, we are joined by NPR space reporter Brendan Byrne to take a close look at where we are in the mission to get people to the red planet. We take a look at the next steps in the Artemis program, and the history and future of robotic exploration of Mars. Find out when we will walk on Mars, where the best places to walk are, and we answer a listener question on the three body problem.

Large Cosmological Structures and JWST Spies a Binary TNO31 Jan 202400:37:43

There's another claim for a violation of the cosmological principle - that all parts of the universe are basically the same on large scales - but Top quark Jim Cooney explains all is not lost for the standard model of the universe, and more observations are needed. The JWST is providing amazing observations near and far, and has now separately measured the composition of two orbiting trans-Neptunian objects (TNOs), confirming that they are made of the same stuff. We explain the implications of this together with the latest space news, a time loop stumper, and walkabout trivia.

Trojan Mysteries and Titan Snowbergs24 Jan 202400:49:07

Strange disappearing islands in the hydrocarbon lakes of Saturn's giant moon Titan may be fluffy icebergs of hydrocarbon snow. If you're on Titan, definitely don't eat the snow, yellow or not. As the Lucy mission heads towards the Trojan asteroids, questions remain about how this strange population of objects formed. We catch up with all the space news, a time travel stumper, and lunar exploration trivia.

Agents of Chaos and Iron Snow10 Jan 202400:42:40

What role has Jupiter played in the existence of our warm and cosy home planet? Has it been bravely using its gravity to keep the inner solar system calm, or did we luck out and escape getting hurtled out of the solar system or dashed to bits in a giant collision? We'll discuss new research that explores exoplanetary systems with multiple large planets and whether habitable planets can co-exist with them. And within our own planet we learn about iron snow at the core mantle boundary and its effects on our magnetic field. Join us for all this cool stuff, plus space news and trivia.

Globular Clusters and Life in Enceladus21 Dec 202300:43:30

New analysis of Cassini data suggests more complex hydrocarbons are part of Enceladus's global sub-surface ocean. We discuss the prospects for life on this tiny moon. The JWST continues to deliver scientific bonanzas, now providing direct observations of globular clusters in very distant galaxies, helping us understand these enigmatic and ancient structures. Join us to explore these mysteries and for space news and special down quark holiday-themed space trivia.

Pluto Cryovolcano and a Cosmological Supervoid13 Dec 202300:42:52

At Pluto's frigid temperatures, even what we breathe is frozen. This can give rise to unusual cryovolcanism, and new research suggests a super cryovolcano tens of kilometers across on the ninth planet (yes, we went there). Speaking of super things, we also review the argument that we are located in a cosmological supervoid and whether than can explain some of the mysteries surround the Hubble constant. Join us for all that, space news, trivia and more.

Mysterious Cosmic Ray and Martian Airglow06 Dec 202300:46:36

The second most energetic cosmic ray (really a particle) ever observed smashed into the Earth a couple of years ago, raising more questions about the origins of these incredibly energetic particles. Solar wind particles meanwhile smash into the planets, and now a green glow from Mars' atmosphere has been observed by one of the many spacecraft exploring the red planet. We also discuss a surprising exoplanet discovery, moon trivia, space news and more.

Ethical Dilemmas in Space Exploration22 Nov 202300:45:29

The astroquarks are joined by Dr. Erika Nesvold, astrophysicist and author of "Off Earth: Ethical Questions and Quandaries for Living in Outer Space" to explore some of the surprising problems people need to think about when going to space. We're busy littering already, but that's just the tip of the asteroid. Join us for a discussion of some of the trickier issues of space exploration, space news, and gravitational wave trivia. The only place you can find that lineup is on Walkabout the Galaxy.

The Origin of Supermassive Black Holes15 Nov 202300:41:07

JWST data confirm early formation of supermassive black holes, less than 500 million years after the big bang. This early formation suggests these monsters start off very large and form with the initial formation of the galaxy. We also take a closer look at the exciting results from the Lucy spacecraft's flyby of the asteroid Dinkinesh and its surprising moon. Join us for all this, space news, and top quark trivia.

Dinky and the S8 Tension08 Nov 202300:51:01

The Lucy spacecraft had its first asteroid encounter, revealing Dinkinesh to be a binary asteroid.  In cosmology, a new simulation with a terrible acronym leaves the "S8 Tension" intact. Models of the expansion of the universe starting with our observations of the cosmic microwave background are in disagreement (tension) with observations of the actual distribution of superclusters of galaxies. Are there errors that haven't been uncovered, or perhaps new physics? Join us for our thoughts on these and other news in space, and some literally mind-blowing trivia.

Chemical Whispers of Life on Mars31 Jul 202400:41:24

The astroquarks assemble for their 365th episode, about 10 years after their first, with a look at a canceled mission to the Moon and tantalizing observations from an ongoing mission at Mars. The Perseverance rover has spied a particularly unusual rock sample with some tantalizing features. Join us for the deets as well as historical astronomy trivia, space news, and more.

The Surprising Interiors of Mars and Venus01 Nov 202300:47:10

New research suggests that Venus, Earth's twin gone bad, may have started off with tectonic plate activity, like Earth. This will help us understand the evolution of Earth-like planets and why they become hothouses like Venus. Our other planetary next-door neighbor, Mars, may have a deep molten magma ocean, revealed thanks to a fortuitous meteoroid impact on the planet whose shaking was recorded by Mars Insight. Join us for these insights, space news, and more.

 

Detecting ETs and Intergalactic Baryons25 Oct 202300:46:20

Fast Radio Bursts are back, this time providing a crucial measurement of the amount of normal matter in the universe. Top quark Jim Cooney explains how the interaction of light from very distant gamma ray bursts reveals the otherwise invisible matter sprinkled in the intergalactic void. Somewhat closer to home, JWST is providing tantalizing glimpses of the composition of extrasolar planets, a technique that may one day discover alien life. Join us for these and other discoveries, space news, and podcast trivia.

Neutron Star Quakes and the Streaming Instability18 Oct 202300:49:25

Images of the distant Kuiper Belt Object Arrokoth add more weight to the pebble accretion model of planetesimal formation via the streaming instability. If that sounds strange, then you'll really love the story about comparing Fast Radio Burst statistics to earthquakes. This study suggests that these energetic bursts of radiation may be produced by quakes on neutron stars. Join us for these stories, space news, and space history trivia.

Pangaea Ultima, Antimatter Gravity, and the Evection Resonance04 Oct 202300:51:21

The next supercontinent could spell bad news for mammals. The equivalence principle passes another test, with antimatter atoms falling just like normal matter atoms, and Josh gets excited about the evection resonance and the role it may have played in the formation of Saturn's rings. Plus, we have top quark trivia and a nerd news rant. Join us!

Short Take: Asteroid Sample and Dark Matter Hopes27 Sep 202300:19:22

Strange and Top discuss the return of the sample from the asteroid Bennu and an intriguing measurement from a dark matter detector in Italy in this, our first Short Take episode. Sadly, the measurement has not been reproduced. Yet. A new detector in Australia will try to confirm the Italian result.

Trouble in the Universe: El Gordo and Dinky20 Sep 202300:48:56

There's more tension in the standard model of the history of the universe. Giant superclusters of galaxies formed early than we thought they could. These collosal structures trace their origins to quantum fluctuations in the early universe. Find out what it all means, plus chthonian planets, asteroid encounters and more on Walkabout the Galaxy.

Ho'oleilana and Weird Spots on Mercury13 Sep 202300:53:41

This episode is about hollows in space on very different scales and for very different reasons. Ho'oleilana is the largest observed structure in the universe, a bubble of sorts defined by great sheets of galactic superclusters whose size is a reflection of acoustic oscillations in the very early universe. Closer to home, we take a look at mysterious hollows on Mercury indicative of some sort of recent geologic activity. Join us to learn about these strange features, space news, radiation trivia and that unmistakable astroquark spark.

Water in the Solar System - Dragoncon 202307 Sep 202300:47:15

The astroquarks report from Dragoncon 2023 on the surprisingly diverse distribution of water in the solar system, where it came from, and the prospects for life on other worlds. We are joined by planetary geologist R. Scott Harris for this special episode with a live audience. This episode of Walkabout the Galaxy also features obscure sci-fi trivia, space news, and your hosts in silly costumes. 

Diamonds, Granite, and Hubble Tension30 Aug 202300:47:44

When we think of all the wonderfully unique things about the Earth as a planet (liquid water on the surface, life, plate tectonics), the existence of lovely granite kitchen countertops doesn't usually make the list. But it turns out granite is uncommon elsewhere in the solar system. But there's a big hot blob of it underneath the lunar surface. We'll explain that, the origin of diamonds on Earth, and take a closer look at the puzzling discrepancy of values of the Hubble constant thanks to JWST. Join us for all that and the first ever Charm Quark trivia.

The Sun Bounces Gamma Rays and a Muon Surprise16 Aug 202300:47:21

The Sun is showering us with far more gamma rays than anticipated according to new measurements from a Cerenkov radiation detector in Mexico. The way those gamma rays are produced is very cool. Also cool: data continue to suggest a significant problem with the so-called standard model of particle physics. Muons are misbehaving, and it may suggest a fifth, previously undescribed and unknown, force of nature. Check out all that cool stuff, silly sponsors and trivia, and space news on this episode of Walkabout the Galaxy.

Lunar Caves for Future Habitation18 Jul 202400:25:42

In this light episode of Walkabout the Galaxy, Josh and Audrey discuss the first confirmation of open spaces in lava tubes connected to lunar pits on the Moon. 200 lunar pits have been observed on the Moon, and now scientists have used radar data to demonstrate that these pits are in fact connected to caverns that could provide future astronauts with a safe haven beneath the lunar surface. Join us on this short walkabout for the full story, trivia, and space news updates.

Rogue Planets Galore and the Age of the Universe09 Aug 202300:49:03

We take a look at two extraordinary astronomical news items in this episode. A deep dive into an astronomical survey has discovered an Earth-sized rogue planet and a Neptune-sized rogue planet. Extrapolating from those discoveries, there may be trillions of Earth-sized rogue planets roaming the galaxy. That's more than the number of stars in the Milky Way! We also explore the question of early galaxies and a model that suggests the universe is older than the standard model. As a bonus, we have some wacky Top quark trivia, space news, and more.

Dark Stars and Water in Hot Places02 Aug 202300:45:55

The JWST has spotted water vapor in the hot inner region of a protoplanetary disk, the same region where rocky planets like are own are expected to form. This suggests water can be incorporated into terrestrial planets during formation, without relying on comet impacts. Much, much further away, a new interpretation of JWST results is consistent with dark stars. They are actually quite bright, but are powered by the annihilation of dark matter rather than by nuclear fusion. Catch up on these discoveries, planetary trivia, and much more with your friendly neighborhood astroquarks.

X-Rays from Mercury and a Different Kind of Gravitational Hole26 Jul 202300:44:29

We think of aurora as an atmospheric phenomenon, but what happens when high energy particles from the Sun directly impact a planetary surface? Mercury reveals another cool planetary twist with auroral-like emission from its surface. Meanwhile, Jim and and Josh are gobsmacked by the old news of a big gravitational potential hump in the Indian ocean caused by upwelling of low-density magma far below. Catch up on all the cool space news with the astroquarks.

 

The Rumble in the Universe12 Jul 202300:52:43

Nature has provided us with exquisitely accurate clocks in the form of pulsars, those rapidly rotating neutron stars whose beams of radiation act like high-powered lighthouses across the galaxy. We discuss the amazing discovery of a deep, low, rumble of gravitational waves across the universe by analyzing the periods of 79 of those pulsar lighthouses. Closer to home, there's evidence for a major climate shift on Mars 400,000 years ago that lines up with changes in Mars's spin. Check it all out on this episode of WtG, with wave trivia and space news too.

All Things Dark: Matter, Energy, and More28 Jun 202300:50:14

Top quark has a field day in this episode with a model for fuzzy dark matter, new data that could shed light on dark energy, and a cool x-ray echo from the supermassive black hole at the heart of our galaxy. Closer to home, we take a look at how JWST is helping us determine if exoplanets have comfortable greenhouse effect atmospheres. Plus, we have a surprising spaceship trivia question and a space travel stumper. 

Earth's Pebble Accretion and the Boring Billion21 Jun 202300:50:30

New analysis of radioisotopes of meteorites and the Earth suggest the Earth formed in only a few million years via a process called pebble accretion. This may mean the Earth's water was incorporated early and gradually rather than through late impacts. Recent determinations of the historical length of the Earth's day suggest it stalled out at 19 hours for a cool billion years, and we still have a ways to go to get to 25 hours when we can all sleep in. Find out about the Earth's history, supermassive black hole mergers, and syzygy trivia.

Supernovae Near and Far14 Jun 202300:46:32

There's a bright supernova in a nearby galaxy, and a very distant supernova made brighter by the beauty of gravitational lensing. In another galaxy, a gargantuan black hole is revealed to be orbited by another supermassive black hole, resulting in a gamma ray flares as it rips through the main black hole's accretion disk. Closer to home, we learn about new asteroid missions and a rapidly warming planet (hint: it's ours). Plus: Harrison Ford and Leonard Nimoy trivia!

Is the Universe Left or Right-Handed?31 May 202300:50:40

Lefty astroquark Jim Cooney leads us on an exploration of what it means for the universe to have chirality. In other words, is there a break in parity in the way galaxies are distributed, or would the universe look the same if we saw its mirror image? The answer and its possible explanation are fascinating. And Josh gets to once again talk about one of his favorite topics, Saturn's rings, and new results on their age.

Scary Things That Can Happen To Planets24 May 202300:48:33

We take a deep dive into the origin of Mars's moons and whether they are chips off the old block. There's no research to explain the mystery of why Mars and the rest of the planets are even here after billions of years, when the solar system seems to be inherently unstable. And astronomers may have caught a star in the act of gobbling up a planet in the first stages of the star's death throes. Catch up on these scary things that can happen to a planet, space news, and Top quark trivia.

Crazy Rings, Watery Moons, and Ancient Black Holes10 May 202300:50:39

We explore the strange ring system of dwarf planet Quaoar, and discuss a new study that suggests that Uranus's four largest moons (which aren't really very large!) may have subsurface salty oceans. In the astrophysical realm, black holes may have emerged from the chaotic soup of energy during the inflation era when the universe was not even minutes old. Add to that some nerdy computer trivia and you've got yourself another episode of Walkabout the Galaxy!

Dark Matter, Deuterons, and a Mixed-Up Protoplanetary Disk11 Jul 202400:42:38

You'll be amazed at how much we can learn from iron meteorites. Who would have guessed that analysis of the compositions of these humble metallic remnants of asteroids would be able to tell us about the shape of the protoplanetary disk? We'll learn about the latest clues to the early history of our solar system, the surprising abundance of deuterons in cosmic rays provides another indicator that we still have a lot to learn about the early universe, and dark matter - well it's still out there, still dark. Join us for all this, space news, nerdy trivia and more.

The Impact of Impacts on Water on Mars26 Apr 202300:49:37

New calculations show how large impacts onto Mars may have boosted its greenhouse effect, helping explain how it was warm enough for all those rivers and lakes billions of years ago. If that explains Mars' early warm climate, it could be bad news for potential for life there. Futher from home, dust has been observed star forming regions in the Small Magellanic Cloud where the abundance of planet-building raw materials is low. Check out these stories, space news, and special top quark trivia.

Live at Nerd Nite with the Moon, JUICE, and M87 Black Hole19 Apr 202300:41:31

We return to Orlando Nerd Nite for a live recording where we take a look at the exciting upcoming missions to the Moon and the ESA mission to Jupiter's moons, JUICE, now on its 8 year journey to its destination. We revisit the amazing image of the supermassive black hole in the galaxy M87, now even amazing-er thanks to the clever implementation of artificial intelligence by some good old fashioned human intelligence. 

MegaCon 2023 and JWST05 Apr 202300:34:42

Space reporter Brendan Byrne becomes an honorary astroquark at MEGACON 2023 where we take a look at some of the recent and landmark discoveries of JWST, including the earliest supermassive black hole and a new era of studying exoplanets. Plus: Anime trivia!

Oumuamua Explained and Dark Matter Near Black Holes29 Mar 202300:48:52

That interstellar comet appears to have gotten its odd behavior from the natural rocket effect of hydrogen gas being released near the Sun and not, sadly, alien rocket technology. The universe is still a cool and interesting place, though, and a new clever measurement of stars orbiting black holes shows evidence for a pile-up of dark matter around the black holes, giving us another way to study this mysterious stuff.

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