Walkabout the Galaxy
298 episodes - English - Latest episode: 22 days ago - ★★★★★ - 106 ratingsAn irreverent and informative tour of the latest, greatest, and most interesting discoveries in astronomy.
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Episodes
Surprises from Bennu and the Milky Way
April 03, 2024 10:10 - 41 minutes - 57.9 MBAnalysis 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 Universe
March 27, 2024 12:45 - 41 minutes - 58.7 MBWe 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?
March 20, 2024 17:08 - 39 minutes - 54.1 MBOne 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 unkn...
Psyche Revisited and Two Giant Black Holes
March 06, 2024 14:54 - 44 minutes - 59.4 MBThe 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 Quasar
February 28, 2024 11:00 - 45 minutes - 62.6 MBSaturn'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 System
February 21, 2024 15:23 - 41 minutes - 57.4 MBWater 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.
When Will We Walk on Mars?
February 07, 2024 14:01 - 41 minutes - 39.3 MBIn 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 TNO
January 31, 2024 11:00 - 37 minutes - 52.1 MBThere'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 ...
Trojan Mysteries and Titan Snowbergs
January 24, 2024 11:00 - 49 minutes - 69.1 MBStrange 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 Snow
January 10, 2024 11:00 - 42 minutes - 58.5 MBWhat 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 ...
Globular Clusters and Life in Enceladus
December 21, 2023 16:30 - 43 minutes - 59.2 MBNew 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 Supervoid
December 13, 2023 11:00 - 42 minutes - 59.1 MBAt 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 Airglow
December 06, 2023 11:00 - 46 minutes - 63.9 MBThe 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 Exploration
November 22, 2023 11:00 - 45 minutes - 41 MBThe 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 Gal...
The Origin of Supermassive Black Holes
November 15, 2023 13:36 - 41 minutes - 56.8 MBJWST 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 Tension
November 08, 2023 11:00 - 51 minutes - 71.5 MBThe 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 ...
The Surprising Interiors of Mars and Venus
November 01, 2023 13:40 - 47 minutes - 66 MBNew 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 Baryons
October 25, 2023 10:00 - 46 minutes - 63.6 MBFast 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,...
Neutron Star Quakes and the Streaming Instability
October 18, 2023 10:00 - 49 minutes - 70.6 MBImages 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 Resonance
October 04, 2023 10:00 - 51 minutes - 72.9 MBThe 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 Hopes
September 27, 2023 13:26 - 19 minutes - 27.1 MBStrange 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 Dinky
September 20, 2023 10:00 - 48 minutes - 67 MBThere'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 Mercury
September 13, 2023 10:00 - 53 minutes - 74.7 MBThis 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 tri...
Water in the Solar System - Dragoncon 2023
September 07, 2023 20:27 - 47 minutes - 53.8 MBThe 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 Tension
August 30, 2023 10:00 - 47 minutes - 67.2 MBWhen 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 JW...
The Sun Bounces Gamma Rays and a Muon Surprise
August 16, 2023 16:08 - 47 minutes - 65.4 MBThe 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 epis...
Rogue Planets Galore and the Age of the Universe
August 09, 2023 14:57 - 49 minutes - 66.7 MBWe 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 ha...
Dark Stars and Water in Hot Places
August 02, 2023 10:00 - 45 minutes - 60.2 MBThe 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 ...
X-Rays from Mercury and a Different Kind of Gravitational Hole
July 26, 2023 10:00 - 44 minutes - 59.8 MBWe 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 Universe
July 12, 2023 10:00 - 52 minutes - 71.6 MBNature 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 o...
All Things Dark: Matter, Energy, and More
June 28, 2023 10:00 - 50 minutes - 69.4 MBTop 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 Billion
June 21, 2023 14:57 - 50 minutes - 71.3 MBNew 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, supe...
Supernovae Near and Far
June 14, 2023 18:48 - 46 minutes - 64.4 MBThere’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?
May 31, 2023 10:00 - 50 minutes - 69.1 MBLefty 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 Planets
May 24, 2023 10:00 - 48 minutes - 64.3 MBWe 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 Holes
May 10, 2023 10:00 - 50 minutes - 68.6 MBWe 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!
The Impact of Impacts on Water on Mars
April 26, 2023 13:54 - 49 minutes - 68.9 MBNew 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 Hole
April 19, 2023 10:00 - 41 minutes - 64.8 MBWe 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 JWST
April 05, 2023 10:00 - 34 minutes - 32.6 MBSpace 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 Holes
March 29, 2023 16:57 - 48 minutes - 68.2 MBThat 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.
Active Volcanism on Venus!
March 22, 2023 10:00 - 47 minutes - 64.9 MBCompelling evidence for recent (1990’s!) volcanic activity on Venus has been un-Earthed, or rather un-Venused, by Robert Herrick through analysis of Magellan radar data. A volcanic vent seems to have roughly doubled in size in 1991. We discuss the difficulties of these observations and the implications for future missions. We also take a look at the role of supermassive black holes in controlling star formation in galaxies and have a numerical Top quark trivia. Warning: this episode gets off...
It's About Time!
March 15, 2023 10:00 - 47 minutes - 70.3 MBWhat time is it on the Moon? It turns out the answer to that is not as easy as just lining it up with a time on the Earth. Worse, it's not even that obvious what time it is on the Earth. That's just one of many topics we explore in this episode, including a discovery that the Milky Way is much larger than previously thought, and tracing water molecules from the interstellar medium step by step into that cool glass you have with dinner. Join us for all that, time trivia, and more.
Sweet Europa Tail
March 08, 2023 11:00 - 42 minutes - 59.7 MBLearn about active asteroids and how the DART mission kind of turned an asteroid into an active asteroid, how impacts into Mercury have given it a dust trail, and we speculate about what might happen if Europa came to Earth. See title for conclusion! It's all about asteroids and dust and impacts on this episode of Walkabout.
Runaway Black Holes and Certified Organic Asteroids
March 02, 2023 00:37 - 47 minutes - 67 MBAstronomers have sighted a supermassive black hole ejected from its host galaxy and creating a wake of stars from intergalactic gas. And if that wasn't enough to blow your mind, closer to home we've seen organic molecules in the material returned from the surface of a near Earth asteroid. Join us for all this, a weird exoplanet, Apollo program trivia, and some surprising tangents.
Whacky Water and Weird Rings
February 15, 2023 11:00 - 43 minutes - 58.8 MBWhere would you go and what would you bring with you if you could explore any object in the universe? Our cosmologist Jim Cooney wants to look for aliens underneath Europa's icy shell. This shell's complicated fractures may owe something to a new form of ice discovered in a delightfully simple experiment. Further out, a dwarf planet beyond Neptune has a ring unlike any we've seen before, and a delightfully complicated experiment may explain the origin of cosmological magnetic fields.
The Trouble with Neutrinos and Other Mysteries
February 01, 2023 11:00 - 49 minutes - 69.3 MBNeutrinos are slippery little buggers, and a new experiment is tightening the net to pin down their itsy-bitsy mass. Closer to home, the Earth's core is a complicated system with changing rates of rotation. We also take a look at the peculiar rings of a distant cometary body, Chariklo, thanks to a new observation by JWST. Join us for all the space news and Mars rover trivia.
The Tiniest Wormhole
January 25, 2023 14:01 - 42 minutes - 59.6 MBScientists have created a simulation of a wormhole in a quantum computer. Top quark helps us understand the significance of this as well as reminds us what the heck a wormhole is anyway. In planetary science, collisions may once again come to the rescue to help explain a mystery. This one is the odd gap in exoplanet sizes. And Down quark gives us an update on the Lucy mission to the Trojan asteroids and its sticky solar panel. Join us for all this, telescope trivia and more.
The Super Earth Assembly Line
January 18, 2023 13:37 - 45 minutes - 62.5 MBOur own solar system is lacking in one of the most common types of planet, the Super Earth. These large rocky planets have a cookie-cutter characteristic that may be explained by the evolution of stuff in a forming system’s disk. Speaking of disks, a mystery about the Milky Way its family of satellite galaxies seems to have been solved. Discover all this with updates from JWST, Artemis, a look ahead to NEO Surveyor, rocket trivia, and a cosmological stumper with your hosts, the astroquarks.
On Top of Nuclear Fusion
January 11, 2023 11:00 - 47 minutes - 64 MBTop quark Jim Cooney rejoins the crew and gives us a deep dive into the breakthrough in nuclear fusion at the National Ignition Facility. Mars rover Perseverance is busy storing samples of Mars for a future mission to bring home, and the Sun may have a 17-year cycle in addition to the well-known 11-year cycle. Ring in the new year with the astroquarks to learn about all this, comet trivia, and more.
All About STEVE and GRBs
December 14, 2022 11:00 - 47 minutes - 68.1 MBThe astroquarks get Down with it as we welcome Dr. Audrey Martin back as the Down astroquark for a discussion of the strange auroral phenomenon known as STEVE (for real), an odd gamma ray burst that may be the result of an unusual stellar merger, and updates on the successful Artemis 1 mission to the Moon.