ScienceNatural SciencesComedy

Walkabout the Galaxy

Joshua Colwell, Adrienne Dove, and James Cooney

An irreverent and informative tour of the latest, greatest, and most interesting discoveries in astronomy.

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22 episodes
fortnightly
Avg 42 min
English

Episodes 22

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#431
August 23 · 35 min
Black Hole Stars and Solar Instabilities
What do you call a very-but-not-so-supermassive black hole completely encased in a warm dense cloud of hydrogen? A hot mess? How about "black hole star", a new category of crazy astronomical object that can explain some of the James Webb Space Telescope's mysterious findings from the early universe. And we're a step closer to understanding our own star with dazzling data from the Inouye Solar Telescope that shows evidence of a fluid instability at the surface that helps explain how the solar corona gets so hot. Join us for this, space news, sci fi trivia and more.
#430
August 16 · 39 min
Dyson Spheres and Interstellar Colonization
Strange and Top are at it again with a deep dive on the physics, psychology, and philosophy of the big questions: is there technologically advanced life out there in the galaxy, and if so, we will ever know? Will we make it out of the solar system, and if so, what would that look like? Join us for all that and a physics question disguized as a trivia question.
#429
August 11 · 36 min
Black Holes Come Back for Seconds and a Rocky Exoplanet with an Atmosphere
Supermassive have such voracious appetites that they create an energetic mess when eating which has a tendency to shoot their food off at very high speeds. New observations show the second course for these monsters as material falls back into them. A rocky exoplanet in the habitable zone has a confirmed atmosphere, checking another box for finding worlds that may have life. Join us for a whimsical tour of the universe on Walkabout the Galaxy.
#428
July 9 · 43 min
Distant Quasars and Earth's Quasi-Moon
Quasars, the energetic engines driven by the voracious appetite of supermassive black holes, have been observed in the very early universe, upending ideas about how long it took to form these behemoths in the first place. New results on a peculiar object tagging along around the Sun with the Earth casts doubt on its origin as a possible fragment of the Moon. And the climate takes a swipe at strange quark for complaining about the heat. Check it all out, plus trivia and space news, on Walkabout the Galaxy.
#427
July 1 · 42 min
I See a Big Moon Rising and a Bright Radio Sky
The astroquarks examine the oft-asked question of why the Moon sometimes looks huge and other times, not so much, and we take a look at the cool mission to grapple and boost the NASA Swift space telescope into a higher orbit. Plus, new observations reveal that the sky is much brighter at radio wavelengths than previously assumed, teaching us something about the population of free electrons. Join us for all this, space trivia, and more.
#426
June 25 · 48 min
Europa's Disappearing Plumes
OG Top Quark Tracy Becker joins us with an update on water plumes from Jupiter's moon Europa, plus intriguing new data of interstellar comet 3I shows it is even older than we thought, with an age approaching that of the Milky Way galaxy itself. A new field of tektites has been discovered, pointing to a previously unknown major impact on the Earth. Join us for all this, space news, trivia and more.
#425
June 4 · 46 min
Second Generation Black Hole Mergers and Solar System Chaos
Exquisitely detailed measurements of the ripples in spacetime from the mergers of black holes now show that some of these merging black holes were, themselves, created by an earlier black hole merging event. While this had been suspected to take place, we now have clear evidence of it. On a less dramatic scale but much closer to home, new simulations of the early solar system suggest the large population of moons of Uranus needed help from a now long lost fifth giant planet to survive. Join us for all this, space news, trivia, and a generally good time.
#424
May 20 · 49 min
Whacky Black Hole Collisions and Strange Uranian Rings
Mysterious bright blue flashes from relatively empty parts of the universe have a new possible explanation involving, what else, black holes. We explore this new idea to explain Luminous Fast Blue Optical Transients (LFBOTs) with black hole collisions, take a peek at the black hole in our own Milky Way, and discuss some puzzling observations of two of the rings of Uranus. Plus, we have a stupid stumper, exoplanet trivia, space news, and a top quark hot take!
#423
May 13 · 47 min
Little Plutino Has An Atmosphere and Making Sense of Saturn
A Plutino, an object that shares Pluto's orbit but which is much smaller than Pluto, appears to have a very thin global atmosphere. We discuss the detection and how such a small body could hold onto even a thin atmosphere, as well as a new model that describes many of Saturn's peculiarities with a recent collision between its big moon Titan and a precursor to the sponge-y moon Hyperion. Join us for all this, space news, astronomy trivia, and much more.
#422
April 28 · 45 min
Superkilonova and Artemis II Recap
Gravitational waves and light combine to reveal what is suspected to be a superkilonova which is much cooler than the name suggests. Cool in the cool way, not the temperature way. Learn about splitting neutron stars and, in our Artemis II recap, we revisit the highs (awesome mission, great astronauts) and lows (broken space toilet) of the mission that took people a record distance from the Earth, and what's next. Plus, trivia, stumper, fake sponsor, and all the nuttiness you've come to love and miss from the astroquarks. We're back!
#422
March 18 · 40 min
A Whisper of a Hint of Primordial Black Holes plus Earth BLOBs
Gravitational Wave observatory LIGO has seen a signature that looks like the merger of primordial (pre-stellar, big bang (not big band!) era) black holes. If confirmed with future observations, this would tell us a lot about the early universe and potentially shed light on dark matter. Finally! Plus, closer to home, the BLOBs in the Earth's mantle help us untangle the complicated past of our magnetic field.
#419
February 25 · 38 min
Supermassive Black Holes Supersoaking Other Galaxies
Supermassive black holes can be terrible neighbors. New research shows that their powerful jets of charged particles can shut down star formation in neighboring galaxies within the galaxy cluster, which is just plain rude. Closer to home, our own Down Quark Audrey Martin is part of a study shedding new light (with the James Webb Space Telescope) on the mysterious L type asteroids, that formed at very high temperatures early in our solar system's history.
#418
February 18 · 46 min
Snowball Earth was Cold and Scary and the Milky Way Magnetic Field is a Mess
The Earth spent some crazy amounts of time (tens of millions of years) completely frozen over. And not, in the grand scheme of things, all that long ago. New research shows the ocean was salty and super-cold. How did life survive? New techniques using radio observations reveal a complicated and twisty galactic magnetic field. Join us for an icy, winter olympics themed episode to find out all this and more.
#417
February 5 · 41 min
Planetary Nebulae and Active Asteroids Get a Closer Look
There's always been a fuzzy line between asteroids and comets, and new observations of asteroids in the vicinity of Jupiter provide a hint to the origin of the mysterious active asteroids that look like asteroids but act like comets. Elsewhere in the galaxy, the famous ring nebula gets a new spectral image that shows the presence of band of iron. Could it be the remnants of a planet like Earth or Mercury that was vaporized when the nebular formed? Tune in for our take on this, space news, trivia and much more.
#416
January 29 · 44 min
A Dark Universe Unveiled
Scientists head to the volcanic fields of Iceland to test instruments for the VERITAS mission to Venus, Artemis II is ready for its historic flight to the Moon, and the Dark Energy Survey reveals the distribution of dark matter on an astounding scale. For mind-blowing astro-stuff, space news, and trivia, join the astroquarks on Walkabout the Galaxy.
#415
January 14 · 46 min
Crazy Spinners in the Asteroid Belt and S8 Tension
The amazing discoveries from the Vera C. Rubin Observatory have already started, and the astroquarks take a look at some close to home. Asteroids bigger than a city block spinning in fewer than 5 minutes are just the beginning, and will change our understanding of the collisional evolution of the asteroid belt. The astroquarks muse on the biggest questions in astronomy today, and one of those, the so-called "S8 Tension" has a possible solution with the help of dark matter and neutrinos. Join us for all that, space news, trivia, and more.
#414
Dec 17, 2025 · 42 min
Cosmic Rays from Everywhere and Stringy Ancient Galaxies
The Parker Solar Probe flies through the Sun's corona, MAVEN has gone silent, and new data shed light on the origins of cosmic rays. JWST's observations of ancient galaxies reveal odd shapes that may be connected to dark matter. Join us for a year-end look at the latest discoveries and space news and much more.
#413
Dec 10, 2025 · 38 min
Interstellar Star Scars and Poop on Mars
We explore the dining and drinking choices for astronauts, complex chemicals discovered in asteroid samples, and untangling the web of scars in the local interstellar cloud to reveal past encounters of the Sun with some hot stellar neighbors. If you wish you had more hot stellar neighbors, you should definitely check out this episode of Walkabout the Galaxy.
#412
Dec 4, 2025 · 46 min
Gravothermalizing and Baby Black Holes
There's a new funky proposal for small black holes in the early universe, and another potential dark matter candidate. Learn about cannibal stars and much more, together with double trivia and space news with your friendly neighborhood astroquarks.
#411
Nov 26, 2025 · 43 min
An Ancient Moon of Mars?
The story behind this investigation is almost more cool than the discovery itself. Microlayers of sediments in Mars' Gale Crater, observed by NASA's Curiosity rover, are indicative of tidal sloshing of water in the lake that once filled the crater. Problem is, the age of the rocks and the magnitude of the tides would require a different moon than the ones currently there. Cool! Join us to hear about that, interstellar comet 3I/Atlas, and much more.

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