Walkabout The Galaxy

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Synopsis

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

Episodes

  • Ho'oleilana and Weird Spots on Mercury

    13/09/2023 Duration: 53min

    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 2023

    07/09/2023 Duration: 47min

    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 Tension

    30/08/2023 Duration: 47min

    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 Surprise

    16/08/2023 Duration: 47min

    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.

  • Rogue Planets Galore and the Age of the Universe

    09/08/2023 Duration: 49min

    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 Places

    02/08/2023 Duration: 45min

    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 Hole

    26/07/2023 Duration: 44min

    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 Universe

    12/07/2023 Duration: 52min

    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 More

    28/06/2023 Duration: 50min

    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 Billion

    21/06/2023 Duration: 50min

    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 Far

    14/06/2023 Duration: 46min

    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?

    31/05/2023 Duration: 50min

    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 Planets

    24/05/2023 Duration: 48min

    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 Holes

    10/05/2023 Duration: 50min

    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!

  • The Impact of Impacts on Water on Mars

    26/04/2023 Duration: 49min

    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 Hole

    19/04/2023 Duration: 41min

    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 JWST

    05/04/2023 Duration: 34min

    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 Holes

    29/03/2023 Duration: 48min

    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.

  • Active Volcanism on Venus!

    22/03/2023 Duration: 47min

    Compelling 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 to a bit of a silly start, so jump ahead to the 24-minute mark if you want to get straight to Venus!

  • It's About Time!

    15/03/2023 Duration: 47min

    What 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.

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