
Astronomy Cast
Take a fact-based journey through the cosmos. Tune in to hear weekly discussions on astronomical topics ranging from planets to cosmology. Hosted by Fraser Cain (Universe Today) and Dr. Pamela L. Gay (Planetary Science Institute), this show brings the questions of an avid astronomy lover direct to an astronomer. Together Fraser and Pamela explore what is known and being discovered about the universe around us. Astronomy Cast is supported thru patreon.com/AstronomyCast.
Latest episodes

May 12, 2025 • 32min
Ep. 755: Intermediate Mass Black Holes
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 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 Kemmler, Andrew Poelstra, Brian Cagle, David Truog, Ed, David, Gerhard Schwarzer, Sergio Sancevero, Sergey Manouilov, Burry Gowen, David Rossetter, Michael Purcell, Jason Kwong

May 5, 2025 • 33min
Ep. 754: K2-18b
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 Kemmler, Andrew Poelstra, Brian Cagle, David Truog, Ed, David, Gerhard Schwarzer, Sergio Sancevero, Sergey Manouilov, Burry Gowen, David Rossetter, Michael Purcell, Jason Kwong

Apr 28, 2025 • 36min
Ep. 753: Why is the Moon's South Pole So Interesting?
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 Group level or higher to be listed in our YouTube videos. Thanks to: BogieNet, Stephen Vei, Jeanette Wink, Siggi Kemmler, Andrew Poelstra, Brian Cagle, David Truog, Ed, David, Gerhard Schwarzer, Sergio Sancevero, Sergey Manouilov, Burry Gowen, David Rossetter, Michael Purcell, Jason Kwong

Apr 21, 2025 • 37min
Ep. 752: Should We Go to the Moon or Mars Next?
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 conversation some nuance. Let's discuss the reasons for each of these worlds. 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 Kemmler, Andrew Poelstra, Brian Cagle, David Truog, Ed, David, Gerhard Schwarzer, Sergio Sancevero, Sergey Manouilov, Burry Gowen, David Rossetter, Michael Purcell, Jason Kwong

Apr 14, 2025 • 34min
Ep. 751: Vacuum Energy
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 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 Kemmler, Andrew Poelstra, Brian Cagle, David Truog, Ed, David, Gerhard Schwarzer, Sergio Sancevero, Sergey Manouilov, Burry Gowen, David Rossetter, Michael Purcell, Jason Kwong

Apr 7, 2025 • 27min
Ep. 750: Supernova Early Warning System
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 before the light show even starts.... Maybe. 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 Kemmler, Andrew Poelstra, Brian Cagle, David Truog, Ed, David, Gerhard Schwarzer, Sergio Sancevero, Sergey Manouilov, Burry Gowen, David Rossetter, Michael Purcell, Jason Kwong

Mar 31, 2025 • 32min
Ep. 749: Dark Energy Changing Over Time
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 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 Kemmler, Andrew Poelstra, Brian Cagle, David Truog, Ed, David, Gerhard Schwarzer, Sergio Sancevero, Sergey Manouilov, Burry Gowen, David Rossetter, Michael Purcell, Jason Kwong

Mar 24, 2025 • 28min
Ep. 748: Fast Radio Bursts
In this intriguing discussion, the hosts dive into the mysteries of fast radio bursts and their unique properties. They highlight the repeating pattern of FRB 1809-16 and explore the role of magnetars in their formation. Listeners learn about the challenges astronomers face in locating these cosmic phenomena and the implications for stellar evolution. The episode also covers advancements in content and research, sparking curiosity about the enigmatic origins of FRBs and their absence of gamma-ray emissions. It's a fascinating leap into the universe's unexplored realms!

Mar 17, 2025 • 29min
Ep. 747: Rogue Planets
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 be listed in our YouTube videos. Thanks to: BogieNet, Stephen Vei, Jeanette Wink, Siggi Kemmler, Andrew Poelstra, Brian Cagle, David Truog, Ed, David, Gerhard Schwarzer, Sergio Sancevero, Sergey Manouilov, Burry Gowen, David Rossetter, Michael Purcell, Jason Kwong

Mar 3, 2025 • 28min
Ep. 746: Dust Storms
Astronomy Cast Ep. 746: Dust Storms By Fraser Cain & Dr. Pamela Gay Streamed live Feb 24, 2025. We have dust storms on Earth and of course the famous dust storms on Mars. There are even dust storms on Titan. What causes these storms and how do they work differently on the worlds in the solar system. But what about the exoplanets? The bane of solar panels, humans, and robots, dust storms have a way of picking up steam (or at least dust) all over the solar system. Hosted by: Fraser Cain and Dr. Pamela L. Gay 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: Andrew Poelstra, BogieNet, Brian Cagle, David, David Truog, Ed, Gerhard, Schwarzer, Jeanette Wink, Siggi Kemmler, Stephen Veit
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