Astronomy Cast

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? D...

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...

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 t...

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 Eddingto...

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 g...

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...

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...

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 tr...

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 y...

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...

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?...

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....

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 a...

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 ex...

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 ot...

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...

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...

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 & cont...

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...

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...

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 hiat...

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...

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 a...

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 smal...

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...