Ep. 783: Cataclysmic Variable Stars
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Hosted by: Fraser Cain () and Dr. Pamela L. Gay () Streamed live on Feb 16, 2026. There are many types of variable stars. Today we’re gonna talk about cataclysmic variable stars, which are the result of a white dwarf stealing material from a companion star. And this whole process makes supervillain Pamela happy. Gravity is the weakest force, but on the scales of stars, it is capable of great violence. In this episode, we look at the wild physics of cataclysmic variables: binary star systems where one star is a predatory compact stellar remnant, while the other is a victimized normal star....
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Ep. 782: Luminous Fast Blue Optical Transients
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Streamed live on Feb 13, 2026. Modern astronomy has found that the Universe can surprise us. Here’s one which astronomers have called Luminous Fast Blue Optical Transients. They’re kinda like supernovas, they’re kind of like gamma ray bursts, but they’re not like them. So what are they? In the distant Universe, are blue light flashes, bright and hard to understand. These objects, uncreatively named "Luminous Fast Blue Optical Transients," are just the kind of puzzle astronomers love. In this episode, we look at their discovery and our current understanding of what they might be. Image...
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Ep. 781: Awakening Black Holes
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Streamed live on Feb 2, 2026. One long standing mystery in astronomy were the quasars. Incomprehensible energy blasting out of a point-like source, billions of light years away. We now know these are actively feeding supermassive black holes, which can turn off and on in a startlingly short period of time. Today: When black holes awaken! Our Universe is filled with sleeping monsters. And sometimes, whether we want it or not, they wake up hungry. In this episode, we take a look at the science behind how and why black holes of all sizes can go from nothing to the triggers of massive high-energy...
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Ep. 780: When Asteroids & Comets Attack!
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Hosted by: Fraser Cain ( ) and Dr. Pamela L. Gay ( ) Streamed live on Jan 26, 2026. We live in a cosmic shooting gallery. It’s not a matter of “if” but “when”! Dinosaurs, blah, blah, blah. You know the drill. But seriously, folks, it’s raining rocks & ice out there! How seriously should we take it? What happens when a variety of different objects hit the Earth? Different kinds of objects affect Earth very differently when they impact. Let's discuss what makes an impactor more or less dangerous. This show is supported through people like you on...
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Ep. 779: Milankovitch Cycles
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Streamed live on Jan 12, 2026. Hosted by: Fraser Cain ( ) and Dr. Pamela L. Gay ( ) Humans live short lives, and from our perspective the seasons are something that come and go with perfect regularity. But astronomers know the terrible truth! And that there are cycles that slowly shift over tens of thousands of years, shifting the cycles and the Earth’s climate. Today we’ll talk about the Milankovich Cycles! The Earth's orbit, tilt, and other physical attributes aren't quite as constant as you might think! Come learn how long-term changes do and don't affect our climate. This show...
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Ep. 778: Dyson Swarms
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Streamed live on Jan 5, 2026. Freeman Dyson asked a fascinating question. What would it look like if a civilization was using all the energy coming from their star? And what form would this take? This introduced the concept of a Dyson Sphere, or more realistically, a Dyson Swarm surrounding a star. But if you’re skeptical about the concept, you’re in good company. This show is supported through people like you on Patreon.com/AstronomyCast In this episode, we'd like to thank: Burry Gowen, Eric Lee, Jeanette Wink, Michael Purcell, Andrew Poelstra, David, David Rossetter, Ed,...
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Ep. 777: The Eddington Limit
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Streamed live on Dec 29, 2025. How big can a star get? This is a calculation made by one of the original pioneers of modern astronomy, Sir Arthur Eddington. And it’s named after him, the Eddington Limit. Now, astronomers are finding examples of giant black holes early in the Universe, calling into question some of Eddington’s assumptions. Let’s explore this fascinating concept! Why are stars sphere-ish? Why do blackholes not eat everything? Why do pulsating stars pulsate? It all comes down to work done by Eddington at the beginning of the last century, and today we're going to look back...
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Ep. 776: The Matter - Antimatter Dichotomy
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Streamed live on Dec 22, 2025. Shortly after the big bang there were almost exactly the same amounts of matter and antimatter in the Universe, but there was just enough of a difference that we live in a matter-dominated Universe. But it didn’t have to be that way! Explaining this mystery has been one of the great mysteries in astronomy, and today we’ll see if there’s been any progress! Why is the Universe the way it is? Specifically, why is it made mostly of matter? This is the question we'll look at today! This show is supported through people like you on...
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Ep. 775: The Hydrogen 21-cm Line
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Streamed live on Dec 15, 2025. Atomic hydrogen is the raw material for stars, but there’s a problem. It’s cold & dark, but it can do a very rare trick, releasing a photon in a very specific wavelength, known as the 21 centimeter line. And thanks to this wavelength astronomers have mapped out star forming regions across the Milky Way, the Universe and into the Dark Ages! This forbidden transition of Hydrogen has led to the mapping of galaxy rotation, a cool classroom application of quantum mechanics, and weirdly no Nobel prize. In this episode, Fraser and Pamela take a look at this...
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Ep. 774: How Does Bad Science Happen?
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Hosted by: Fraser Cain and Dr. Pamela L. Gay. Streamed live on Nov 8, 2025. [Editor's Note: Fraser says "Episode 773" at the head of the show. Not to worry, he was just confused. They recorded a few episodes out of sequence. I fixed the issue in the regular non-FullRaw episode.] Scientific expertise is under attack on all fronts with concerns coming from politicians and the public. While most of this is unwarranted and politically motivated, there can be germ of truth. Bad science does happen, but how? How is it that papers that very few believe still make it through peer review and to...
info_outlineStreamed live on Nov 8, 2025.
With the arrival of the comet 3I/Atlas (Asteroid Terrestrial-impact Last Alert System), the world is getting a crash course in comets, their behavior, and of course their tails. Today we’re going to talk about comets and their tails, why they exist, how they grow, why they can be different colors and how they can be sometimes point AT the Sun.
Comets are one of the most animated and ephemeral targets for astronomy. From night to night they can change in shape and color, and every nuance tells us something. In this episode, we decode blue tails, green cores, forward-facing plumes, and other weird and awesome details observed with these icy visitors.
This show is supported through people like you on Patreon.com/AstronomyCast
In this episode, we'd like to thank: Andrew Poelstra, BogieNet, Brian Cagle, Burry Gowen, David, David Rossetter, Ed, Gerhard Schwarzer, Jason Kwong, Jeanette Wink, Michael Purcell, Sergey Manouilov, Siggi Kemmler, Sérgio Sancevero