Walkabout the Galaxy

Walkabout the Galaxy

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

Episodes

May 21, 2025 47 mins

A major update to the predicted end of the universe has it coming much earlier than previously anticipated. However, we still have plenty of time to get our affairs in order, and the update has to do with spaghettification, and anything with spaghettification can't be all bad. We also talk about active asteroids, your ideal night sky, and cosmological trivia. 

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We get lucky and catch a rogue supermassive black hole in the act of slurping up a star as it meanders through a distant galaxy. Closer to home, the detection of a second trinary, or triple, system in the Kuiper Belt beyond the orbit of Neptune bolsters the streaming instability theory of planet formation. We talk about all that and what it has to do with the Tour de France, as well as space news and trivia.

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The asteroid Vesta may be a fragment of a much larger protoplanet, and astronomers examine old data to discover a large molecular cloud lurking right in the solar system's backyard. Get all the details, plus habitable exoplanets get another look, space news, and trivial matters with your friendly neighborhood astroquarks.

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NASA's Lucy mission had a picture perfect encounter with the asteroid Donaldjohanson on its way to the first ever flybys of Trojan asteroids. Discoveries of ancient supermassive black holes challenge theories of their formation. If dark matter is composed of ultralight particles (lighter than a neutrino), that could resolve the mystery. Join us for these and other cosmic discoveries, space news, trivia, and more.

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The astroquarks discover hot takes and explore the nature of ice, the origin of Earth's water, and the trouble with the singularities at the hearts of black holes. Plus, we have a stumper, astronomical trivia, and much more. 

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Venus's extra-thick crust may be extra chewy, allowing convection to occur and helping power volcanoes into the current era. New observations of the distant universe, meanwhile, show that dark energy may not have behaved as expected in the standard cosmological model. We'll break it all down for you together with space news and trivia with your friendly neighborhood astroquarks.

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April 2, 2025 49 mins

A survey of nearby stars establishes the rate of supernovas in our general neighborhood. Evidence indicates we had nearby stellar explosions at the times of two mass extinctions. Those supernovas may have decimated the ozone layer and contributed to extinctions and climate changes. Plus, we recorded on April 1 and take a look at silly April 1 science papers, and we get tilted with our trivia and space news. Join us, won't you?

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If there are Hycean worlds and if they have a certain kind of microbial life and if there is enough of it, JWST might be able to see the chemical products of that in the planet's atmosphere. We take a look at that, debris from neighboring stars entering our solar system, and the first results from the Euclid space telescope. Join us for all this plus a hilarious double stumper and more.

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March 19, 2025 51 mins

There are exciting new observations from recent lunar missions, a possible chunk of the Moon keeping us company, and an intriguing observation supporting the theory that the entire universe is inside a black hole! Get inside the event horizon with the astroquarks for all the space updates, trivia, and more.

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We take a look at the formation and structure of the Oort cloud of comets which is spherical at large distances but has a spiral structure in its inner regions. And, after all this time, there's a surprising twist on the nature of the iron mineral that gives Mars its reddish hue. Also hiding in plain sight is a dwarf galaxy in the neighborhood of the Andromeda galaxy, our largest companion galaxy. Join us for a discussion of these ...

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February 26, 2025 36 mins

Lunar exploration continues to accelerate, and there's a new longest "structure" in the universe. Quipu is a quasi-alignment of clusters of galaxies stretching over 1 billion light years. Structure is in cynical quotation marks because these objects are not bound or connected to each other in any way, but their arrangement is a natural consequence of the evolution of the universe. If we happen to be in a Quipu-like structure oursel...

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The more measurements we make of the expansion of the universe, the more it seems as though Hubble Tension is not a problem with our data but a problem with our understanding of the expansion of the universe. We'll talk about that, and some cool new observations closer to home, including a disintegrating exoplanet that is giving us a unique peak into a planet's insides. Join us for all this and more, including space news and trivia...

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Juno reveals a surprise about the interior of Jupiter's volcanic moon Io, and the OG young variable star T Tauri is getting ready to fade from view thanks to its dusty neighbors to the south. Speaking of dust, that's what gets kicked up when comets collide, and a new survey examines the cometary belts around dozens of star systems, providing a detailed look at the outer reaches of exoplanetary systems. Join us for all this, sample ...

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January 22, 2025 44 mins

The discoveries from the James Webb Space Telescope keep coming. After showing that galaxies formed far earlier than we thought, we now have a better understanding of what was going on in the early universe. Those little red dots spied by JWST are actually the glow of heated dust and gas from supermassive black holes, and not the glow from billions of stars as had been thought. Closer to home, did the Earth sport a ring for a few m...

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Pluto and its largest moon, Charon, orbit each other with gazes lovingly fixed on each other, held in place by a romantic tidal attraction. But Charon's large size has always been difficult to explain. New simulations show that their love affair may have started at the beginning with a "Kiss and Capture" collision, much gentler than the devasting impact that formed our own Moon. Hear all about that, Centaurs, space news, space triv...

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We kick off 2025 with oddities from quasi particles, to cosmic rays, to the moons of Pluto. What has mass when it moves in one direction and doesn't when it moves in another direction? How do thunderstorms on Earth interact with cosmic rays? What is up with Pluto's moons? Join us as we tackle these questions as well as the stumper and special top quark trivia. It's all part of the package in an episode of Walkabout the Galaxy.

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December 18, 2024 39 mins

We know about extinct comets and active asteroids, but now we've got something in between: dark comets, whose orbits indicate cometary activity, but we can't see it! We'll get the scoop on these interesting objects, a flare from a supermassive black hole, and a twist on the question of the age of Saturn's rings. Plus, we have our end-of-the-year rocket launch roundup, and a special astrophysical FLOD stumper for top quark Jim Coone...

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December 11, 2024 37 mins

Top quark Jim Cooney explains why making big blobs is hard and how new observations are helping us understand how the universe made big immensely big blobs more commonly known as giant elliptical galaxies. Nature loves to make a disk, and we love to tell you all about the cool things nature does, including a solid state greenhouse on ancient Mars that may have produced a huge buried supply of water to create giant rivers near its s...

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November 27, 2024 43 mins

It's a good news bad news story with the detection of the neutrino fog. This signal from solar neutrinos may confound our search for certain dark matter candidates, but at least we know our detectors are very, very sensitive! We also take a look at magnetic fields in the outer solar system, specifically why Uranus's magnetosphere was so weird when we visited in 1986, and what tiny grains from a near Earth asteroid may be telling us...

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November 20, 2024 41 mins

If you're speaking English, not Latin, do you really have to say "supernovae" instead of "supernovas"? Also, they are, in some sense, created equally: explosion of a white dwarf, but the outcomes are not all equal. You are welcome for this grammatical tangent, and please enjoy our fun discussion about weird tesserae (more Latin!) on Venus and the whole standard candle story of type 1a supernovae gets a rewrite. On this episode of W...

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