Astronomy Cast

Astronomy Cast Ep. 786: Wolf-Rayet Stars By Fraser Cain & Dr. Pamela Gay Streamed live on Mar 9, 2026. You think the Sun is a terrifying ball of fire and fury? Wait until you learn about today's topic: Wolf-Rayet stars! These are massive, dying stars hurling their outer layers out into space before detonating as supernovae. Big stars live brief lives, and Wolf-Rayet stars are the punctuation mark we see before things go supernova. Image Credit: NASA, ESA, CSA, STScI; Science: Yinuo Han (Caltech), Ryan White (Macquarie University); Image Processing: Alyssa Pagan (STScI) Learn more here: https://science.nasa.gov/asset/webb/w... This...

Astronomy Cast Ep. 785: Magnetars By Fraser Cain & Dr. Pamela Gay Streamed live March 6, 2026. Magnetars are a special type of neutron star with physics that defy comprehension. Magnetic fields so powerful they could strip you apart at an atomic level. But, where do they come from? So many mysteries to uncover about magnetars. Back in December 2004, a gamma rays washed out cameras and zotted satellites as a star on the other side of the Milky Way shifted around its magnetic fields. Magnetars are violent that way. In this episode of Astronomy Cast, Fraser and Pamela take on this tiny terrible monsters...

Astronomy Cast Ep. 784: Pulsar-Powered Science By Fraser Cain & Dr. Pamela Gay Streamed live on Feb 16, 2026. Pulsars are dead stars and fascinating in their own right, but astronomers can use their predictable rotation for exploring the cosmos in a series of amazing ways. We can detect gravitational waves, navigate the solar system, test general relativity and find exoplanets. Pulsars are the time keepers of the sky, with their precise ticking allowing researchers to track gravitational waves, find exotic planets, and study weird relativistic effects. Come learn about how pulsars can be used to explore our universe. Image credit: NASA/CXC/ASU...

Astronomy Cast Ep. 783: Cataclysmic Variable Stars By Fraser Cain & Dr. Pamela 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...

Astronomy Cast Ep. 782: Luminous Fast Blue Optical Transients By Fraser Cain & Dr. Pamela Gay 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...

Astronomy Cast Ep. 781: Awakening Black Holes By Fraser Cain & Dr. Pamela Gay 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...

Astronomy Cast Ep. 780: When Asteroids & Comets Attack! By Fraser Cain & Dr. Pamela 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 Patreon.com/AstronomyCast In...

Astronomy Cast Ep. 779: Milankovitch Cycles By Fraser Cain & Dr. Pamela Gay Streamed live on Jan 12, 2026. 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 is supported through...

Astronomy Cast Ep. 778: Dyson Swarms By Fraser Cain & Dr. Pamela Gay 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...

Astronomy Cast Ep. 777: The Eddington Limit By Fraser Cain & Dr. Pamela Gay 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...

Astronomy Cast Ep. 776: The Matter - Antimatter Dichotomy By Fraser Cain & Dr. Pamela Gay 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...

Astronomy Cast Ep. 775: The Hydrogen 21-cm Line By Fraser Cain & Dr. Pamela Gay 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...

Astronomy Cast Ep. 774: How Does Bad Science Happen? By Fraser Cain & Dr. Pamela Gay Streamed live on Nov 8, 2025. 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 publication? Why do professors at prominent universities get quoted saying things that seem to be fiction? In this episode, we consider the case for letting potentially impossible things...

Astronomy Cast Ep. 773: What Would You Do With $1 Billion For Astronomy? By Fraser Cain & Dr. Pamela Gay Streamed live on Nov 9, 2025. We are powerless fans of space exploration. But what if some fool gave us the authority and funding to make our space dreams a reality? Someone asked us what we'd do with a billion dollars. What missions? Which telescopes? But what if we had more? 100 Billion! A trillion! All the monies! You keep asking, and this week we answer you! Come hear what Fraser and Pamela would do if they were given complete control over $1billion that had to...

Astronomy Cast Ep. 772: 2025 Gift Guide By Fraser Cain & Dr. Pamela Gay Streamed live on Nov 9, 2025. It's time once again for our annual gift-giving guide. We've got recommendations for books, movies, TV shows, games, and of course astronomy gear to satisfy the space nerds in your family. The Christmas season is almost upon us, and with it comes excuses to inject science into the lives of those you love... or ask for them to give you that book, lens, or art print you already know you'll love. In this episode, Fraser and Pamela share the things they think would make good...

Astronomy Cast Ep. 771: Comet Tails By Fraser Cain & Dr. Pamela Gay Streamed 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...

Astronomy Cast Ep. 770: The Ethics of Mars Exploration By Fraser Cain & Dr. Pamela Gay Streamed live on Nov 3, 2025. Hosted by: Fraser Cain and Dr. Pamela L. Gay. It is arguable that humanity now has the technological ability to live on Mars. It would be done at enormous expense and sacrifice, and there are some tricky problems that we haven't solved yet. Although we could live on Mars, should we? There is a famous quote from Jurassic Park: "Your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should." This concept is played...

Astronomy Cast Ep. 769: Little Red Dots By Fraser Cain & Dr. Pamela Gay Streamed live on Oct 20, 2025. New instruments bring new mysteries, and when James Webb came on line it uncovered a collection of strange, compact, bright objects shifted deeply into the red end of the spectrum. These were dubbed "Little red dots" or LRDs. And the astronomical community continues to puzzle over what they are. When JWST first peered into the distant past, it discovered the early universe had a rash of little red dots. Their existence just 450 million years after the big bang meant either galaxies were forming way...

Astronomy Cast Ep. 768: Comets' Unpredictability By Fraser Cain & Dr. Pamela Gay Streamed live on Oct 13, 2025. So it's been decades since we've seen a bright comet in the sky. And actually there was a pair — Hale-Bopp and Hyakutake. And then, silence! And unmet promises by the Universe to give us a bright comet. Comets are unpredictable, and they arrive precisely when they intend to. Is it time again for a bright comet? If you asked us in January if 2025 was going to have any outstanding comets would fly through the Solar System, we would have (and we did) say "no." And we...

Astronomy Cast Ep. 767: Black Holes in Extreme Circumstances By Fraser Cain & Dr. Pamela Gay Hosted by: Fraser Cain and Dr. Pamela L. Gay Streamed live on Oct 6, 2025. You can only describe a black hole by its mass and its spin. And maybe it's charge. But allow us to propose a new criteria: the personal experience. Some black holes have seen things… Experienced the laws of physics at their most extreme. And today we'll tell their stories. The more of the sky we observe, the more bizarre situations we find black holes in. Let's explore! This show is supported through people li...

Astronomy Cast Ep. 766: How Spacecraft End By Fraser Cain & Dr. Pamela Gay End-of-Life Planning for Your Spacecraft! Streamed live October 1, 2025. Your spacecraft has reached the end of its mission. You've done everything you can to keep it operational, but now it's time to say goodbye. How do space agencies deal with spacecraft to shut them down gracefully, protect future missions and life on other worlds. So, the time has come to see your mission across the Rainbow Bridge. How exactly do you say goodbye? Let's discuss.

Astronomy Cast Ep. 765: Rockets vs The Environment By Fraser Cain & Dr. Pamela Gay Streamed live on Sep 22, 2025. We don't launch a lot of rockets every year, so their impact on the environment is minimal compared to other forms of transportation. But that number is steadily increasing with rates that we'll have to take seriously. What's the current and future impact of rockets on the environment Rocket facilities are often surrounded by wildlife preserves and they always fly through our atmosphere. Let's take a look at how launches do and don't impact the environment around them from the surface of Earth...

Astronomy Cast Ep. 764: Cleared For Launch! By Fraser Cain & Dr. Pamela Gay Streamed live September 17, 2025. This week, we look at the process behind rockets getting licensed to launch, and everyone around the pad getting notified to stay away as T-0 approaches. (Can you say "errant boat"?) We have a saying around here: "One does not simply book a return trip from a rocket launch." That's because they are an intensely complex chain of events that need to go right before it's wise to let that rocket leave the launchpad.

Astronomy Cast Ep. 763: Interstellar Comets By Fraser Cain & Dr. Pamela Gay Streamed live Sep 8, 2025. Welcome to the first episode of our 19th season! This week we look at objects coming from other solar systems that come passing on by our Sun. During the summer hiatus the 3rd interstellar object was discovered: Comet 3I/ATLAS! So now we have 3 different interstellar interlopers to compare & contrast. What are we starting to learn about other star systems from this small sample size and how will our detection get even better? [Editor's note: HiRISE's telescope is 1/2 meter.]

Astronomy Cast Ep. 762: Science in Crisis - NASA's New Budget By Fraser Cain & Dr. Pamela Gay Streamed live on Jun 30, 2025. Hosted by: Fraser Cain and Dr. Pamela L. Gay Normally we try to end the season on a high note. But there's unfolding news that we just HAVE to cover before we leave you for the summer. NASA's new budget is here, and it's 25% smaller. We'll cover what the changes are and try to understand the implications. It's a bad decade to be a researcher. We're going to look at why, and what US cuts will mean for the world...

Astronomy Cast Ep. 761: It's Here! The Vera Rubin Observatory By Fraser Cain & Dr. Pamela Gay Streamed live June 25, 2025. The time has come. The mighty Vera Rubin Observatory has finally come on line and delivered its "first light" images. And by Pamela's rules that means we get to talk about it! So let's do that! After decades of waiting, we have images from Vera Rubin Observatory! SUPPORTED BY YOU This Episode is made possible thanks to our Patrons on Patreon. Join at the Galaxy Group level or higher to be listed in our YouTube videos. Thanks to: BogieNet, Stephen Vei, Jeanette...

Astronomy Cast Ep. 760: What to Look For This Summer By Fraser Cain & Dr. Pamela Gay Streamed live on Jun 16, 2025. It's almost time for our annual summer hiatus, but before we go, we wanted to direct you towards all the fun and space stuff we'll be enjoying this summer. We've got meteor showers, planets, rocket launches, TV shows, movies! Here's what's good. In a couple of weeks, we'll go on hiatus, but we want to make sure you are ready for stuff we can anticipate happening. SUPPORTED BY YOU This Episode is made possible thanks to our Patrons on Patreon. Join...

Astronomy Cast Ep. 759: The Commercial Space Program By Fraser Cain & Dr. Pamela Gay Streamed live on Jun 9, 2025. Humanity has turned its focus back to the Moon, sending a fleet of spacecraft to the lunar surface. Some are run by the government, but there's a whole new group of commercial landers bearing instruments to the lunar surface. Is this the future of lunar exploration? Space used to be a place occupied by government-funded and military missions, but today, we're seeing the rise... and fall (somersault, crash, and explosion) of missions with commercial design and funding. Let's talk about how this is...

Astronomy Cast Ep. 758: Non-Roving Rovers By Fraser Cain & Dr. Pamela Gay Streamed live on May 26, 2025. Some of our favorite robots are rovers currently roving around the surface of the Moon & Mars. But there's some pretty tricky terrain out there and engineers are scheming up clever ways to explore other worlds inspired by life that crawls, slithers, hops and flies. As we explore more surfaces and more complex surfaces throughout the solar system, mission teams are designing robot explorers that don't sit still and also don't rove. In this episode, we're going to take a look at the new technologies that...

Astronomy Cast Ep. 757: CubeSats By Fraser Cain & Dr. Pamela Gay Streamed live on May 19, 2025. Computers are getting smaller, faster and more capable, which has enabled an entirely mew class of satellites: CubeSats. A mission small enough that you can hold it in your hands, and yet powerful enough to even travel to other planets and send messages home. Every year, our electronics seem to get smaller and more powerful, with today's smart watches being more fully featured than the computers Pamela and Fraser had as little kids. These tiny processors, sensors, and transmitters are allowing tiny satellites with powerful functionality...

Astronomy Cast Ep. 756: SphereX By Fraser Cain & Dr. Pamela Gay Streamed live on May 12, 2025. NASA's newly launched SphereX mission is up & operational and has completed its initial checkout and "first light". Everything looks good! And now it's starting its science operations. And that's good enough for Pamela! And THAT means we can talk about it. So let's do that! There's a new space telescope in town (or at least in LEO). Let's check out what it's looking at and looking to do. SUPPORTED BY YOU This Episode is made possible thanks to our Patrons on Patreon. Join at the Galaxy...

Astronomy Cast Ep. 755: Intermediate Mass Black Holes By Fraser Cain & Dr. Pamela Gay Streamed live on May 5, 2025. Hosted by: Fraser Cain and Dr. Pamela L. Gay. There are stellar-mass and supermassive black holes. But very little evidence of anything in between. Where are all the intermediate-mass black holes that should be the building blocks of the biggest ones? Actually, the science has been accelerating rapidly and we now know of hundreds of them. The question marks in our understanding are slowly getting replaced with data. Let's review what we now know about intermediate mass black holes and their origins. SUPPORTED...

Astronomy Cast Ep. 754: K2-18b By Fraser Cain & Dr. Pamela Gay Streamed live on Apr 28, 2025. You've heard the news! Astronomers are reporting the discovery of biosignatures at K2-18b. Is this proof of life or should we all be more skeptical? It's in the news and people are claiming aliens... but is it aliens? Let's see what the data actually says. SUPPORTED BY YOU This Episode is made possible thanks to our Patrons on Patreon. Join at the Galaxy Group level or higher to be listed in our YouTube videos. Thanks to: BogieNet, Stephen Vei, Jeanette Wink, Siggi...

Astronomy Cast Ep. 753: Why is the Moon's South Pole So Interesting? By Fraser Cain & Dr. Pamela Gay Streamed live on Apr 21, 2025. I'm sure you've heard that all eyes are on the Moon's southern pole. This is where various NASA and Chinese missions are targeting. What makes this region so special and what are the special challenges that explorers will face. From TV shows to real-world missions, it seems like everyone just wants to explore the Moon's South Pole. But why? Learn here! SUPPORTED BY YOU This Episode is made possible thanks to our Patrons on Patreon. Join at the Galaxy...

Astronomy Cast Ep. 752: Should We Go to the Moon or Mars Next? By Fraser Cain & Dr. Pamela Gay Streamed live on Apr 16, 2025. Hosted by: Fraser Cain and Dr. Pamela L. Gay There is an ongoing debate on where NASA should go next with humans: to the Moon or Mars. (Or maybe an asteroid or one of Mars' moons). We are on the verge of sending humans back to the Moon. At the same time others would prefer we focus our exploration on Mars. It's a tough choice because there are costs and benefits to both. Let's try to give this...

Astronomy Cast Ep. 751: Vacuum Energy By Fraser Cain & Dr. Pamela Gay Streamed live on Apr 7, 2025. Hosted by: Fraser Cain and Dr. Pamela L. Gay. Even empty space isn't empty. It's filled with the quantum fluctuations of spacetime itself. Which can be measured with famous experiments like the Casimir Effect. There is a surprising amount of energy in space itself, which has led to some interesting theories about how the future of the Universe might evolve. You can't get something from nothing but sometimes that nothing is something you can get something from. SUPPORTED BY YOU This Episode is made possible...

Astronomy Cast Ep. 750: Supernova Early Warning System By Fraser Cain & Dr. Pamela Gay Streamed live on Mar 31, 2025. Hosted by: Fraser Cain and Dr. Pamela L. Gay When enormous stars detonate as supernovae they release a burst of neutrinos that can be the first sign of a coming explosion. Now, astronomers have built a network to watch for that flash of neutrinos, and help direct their telescopes for when the sky show begins. Supernovae explosions occur in stages, with neutrinos being emitted hours before photons. If we can accurately detect those neutrinos, we might just be able to get on target...

Astronomy Cast Ep. 749: Dark Energy Changing Over Time By Fraser Cain & Dr. Pamela Gay Streamed live on Mar 24, 2025. The Hubble Tension is a vexing problem, with astronomers measuring the expansion of the Universe at different points in its history and getting different results. Errors have mostly been ruled out, which leaves the potential for new physics. Has the strength of dark energy been changing over time? We thought Dark Energy was constant with time, but new results from DESI say maybe not, and honestly, if it wasn't constant the Hubble Tension would be a whole lot easier to solve. SUPPORTED...

Astronomy Cast Ep. 748: Fast Radio Bursts By Fraser Cain & Dr. Pamela Gay Streamed live on Mar 17, 2025. For the briefest of moments, some dead stars can flash brighter than their entire galaxy (in Radio light) and then live to do it again and again. It's time for an update on fast radio bursts, a phenomenon we've only known about for a few decades. In this time astronomers have learned a tremendous amount them. They're not solved, but we're getting closer! SUPPORTED BY YOU This Episode is made possible thanks to our Patrons on Patreon. Join at the Galaxy Group level or...

Streamed live on Mar 10, 2025. Hosted by: Fraser Cain and Dr. Pamela L. Gay Most planets orbit stars. That's the rule, right? Well, maybe not. In fact the vast majority of planets could be floating freely through the Milky Way. Today we're gonna talk about rogue planets. Sometimes planets just go rogue. Let's learn about planets living free from stars. Show Notes: Earth's Dust Storms Mars' Global Dust Storms Dust Storms on Titan Potential Dust Storms on Exoplanets SUPPORTED BY YOU This Episode is made possible thanks to our Patrons on Patreon. Join at the Galaxy Group level or higher to...