Astronomy Cast

Astronomy Cast Podcast

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 (SIUE), 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 through individual donations and the sponsorship of Swinburne Astronomy Online.

Ep. 580: Exploding Dwarfs
Astronomy Cast Ep. 580: Exploding Dwarfs By Fraser Cain & Dr. Pamela Gay So you think that a white dwarf star is the end of a stellar life, and it's all downhill from there, a long, slow cool down towards the end of everything. But in some situations even dead stars can get exciting again, briefly becoming some of the brightest objects in the Universe. And maybe, just maybe, the last exciting thing that'll ever happen in the Universe....

Ep. 579: White and Black Dwarf Stars
Astronomy Cast 579: White and Black Dwarf Stars by Fraser Cain & Dr. Pamela Gay I've got some bad news for you. Stars die. At some point in the next few billion years or so our Sun is going to start heating up, using up all the fuel in its core, and then eventually die, becoming a white dwarf. It'll then slowly cool down to the background temperature of the Universe, becoming a black dwarf. Let's learn about this fascinating process....

Ep. 578: Venus Updates - or - Life on Venus?!?
by Fraser Cain & Dr. Pamela Gay So have you heard the news? Of course you have. Evidence of phosphene on Venus. Which could be a biosignature of life on our evil twin planet. There have been a lot of surprising stories about Venus, so let's get you all caught up!...


Ep. 577: Mars in Opposition
Astronomy Cast 577: Mars in Opposition by Fraser Cain & Dr. Pamela Gay Every 2 years or so Mars lines up nicely with the Earth. It takes only 2 minutes to communicate with the rovers. You can see the polar ice caps in a small telescope. And it's the best time to send your spacecraft to the Red Planet.  Oct 3rd: Moon & Mars conjunction, 1.1° separation. Oct 6th: Mars opposition. Dec 21st: Jupiter/Saturn conjunction, 0.1° separation! Feb 18th "Percy" lands on Mars' Jezero crater....

Ep. 576: Summer Stargazing Special
Astronomy Cast Ep. 576: Summer Stargazing Special by Fraser Cain & Dr. Pamela Gay It's time once again for Astronomy Cast to go on hiatus. You've got a couple months on your own to explore the night sky. But before we say goodbye, we'd like to make a few suggestions....

Ep. 575: Observing The Moon
Astronomy Cast Ep. 575: Observing The Moon by Fraser Cain & Dr. Pamela Gay As amateur astronomers, we curse the Moon every month. Seriously! Why doesn't someone get rid of that thing! This week, something occurred to us. What if we actually pointed our telescopes at the Moon? What would we see? The Lunar "X" that Fraser talked about will be visible this Friday, June 26th! So go out with binoculars or a telescope and enjoy!...


Ep. 574: Trojan Asteroids
Astronomy Cast Ep. 574: Trojan Asteroids by Fraser Cain & Dr. Pamela Gay We imagine the asteroid belt as a place where all the rocks hang out in the solar system. But there are 2 huge bands of asteroids that orbit the Sun with Jupiter called the Trojans. And soon we may actually get a chance to see them up close!...

Ep. 573: Exoplanet Atmospheres
Astronomy Cast Ep. 573: Exoplanet Atmospheres Not only have astronomers discovered thousands of exoplanets, but they're even starting to study the atmospheres of worlds thousands of light years away. What can we learn about these other worlds and maybe even signs of life....

Ep. 572: Twists in Planet Formation
Astronomy Cast Ep. 572: Twists in Planet Formation by Fraser Cain & Dr. Pamela Gay We're all looking to the next generation of exoplanetary research where we get planets directly. But astronomers are already making great strides in directly observing newly forming planets help us understand how our solar system might have formed....


Ep. 571: Extreme Binaries
Streamed live on May 22, 2020. So we're familiar with regular binary stars. Two stars orbiting each other. Simple. Of course the Universe has come up with every combination of things orbiting other things, and this week we look at some extreme examples....

Ep. 570: Discovering Comets
Astronomy Cast Ep. 570: Discovering Comets Discovering comets is one of the fields that amateurs can still make a regular contribution to astronomy. But more and more comets are getting found by spacecraft, automated systems and machine learning. This week we'll talk about how comets are discovered and how you can get your name on one!...


Ep. 568: In Situ Resource Utilization
The key to surviving in space will be learning how to live off the land. Instead of carrying all your fuel, water and other resources from Earth, extract them locally from your destination. It's called In Situ Resource Utilization, and if we can figure it out, it'll change everything....

Ep. 567: When Satellites Need a House Call
567: When Satellites Need a House Call Astronomy Cast 567: When Satellites Need a House Call by Fraser Cain & Dr. Pamela Gay Space is really far away, so when you send a satellite out into the void, that's pretty much the last you're going to be able to work on it. And if anything goes wrong, too bad, you're out a satellite. But a new test has shown that it's possible to actually visit and fix a satellite in space. Maybe we don't have to throw them all away after all....

Ep. 566: When Comets Fall Apart
566: When Comets Fall Apart Astronomy Cast 566: When Comets Fall Apart by Fraser Cain & Dr. Pamela Gay As everyone knows, the Universe owes us a bright comet. There have been a lot of promising candidates, but in the end, they always fail to live up to our expectations. Comets keep on breaking up with us....


Ep. 565: When Worlds Collide
565: When Worlds Collide Astronomy Cast 565: When Worlds Collide by Fraser Cain & Dr. Pamela Gay So much of our Solar System has been shaped by enormous collisions early on in our history. Seriously, the nature of every planet in the Solar System has some evidence of massive impacts during some point in its history....

Ep. 564: Mini Moons
564: Mini Moons Astronomy Cast 564: Mini Moons by Fraser Cain & Dr. Pamela Gay Last month astronomers announced that they had detected a tiny asteroid that had been captured by the Earth's gravity well and had been sharing our orbit for a few years. Today, let's talk about the smallest moons in the Solar System....

Ep. 563: White Dwarf Mergers
563: White Dwarf Mergers Astronomy Cast 563: White Dwarf Mergers by Fraser Cain & Dr. Pamela Gay White dwarfs are usually about 60% the mass of the Sun, so it was a bit of a surprise when astronomers found one that was almost exactly twice that. What happens when white dwarfs merge?...


Ep. 562: Dealing with COVID-19 and the Changes it will Bring
562: Dealing with COVID-19 and the Changes it will Bring Astronomy Cast 562: Dealing with COVID-19 and the Changes it will Bring by Fraser Cain & Dr. Pamela Gay Pamela and Fraser discuss the implications of COVID-19 and it's changes on the world, and what we all can do during this time....

Ep. 562: Dealing with COVID-19 and the Changes it will Bring
562: Dealing with COVID-19 and the Changes it will Bring Astronomy Cast 562: Dealing with COVID-19 and the Changes it will Bring by Fraser Cain & Dr. Pamela Gay Pamela and Fraser discuss the implications of COVID-19 and it's changes on the world, and what we all can do during this time....

Ep. 561: Remembering Katherine Johnson
561: Remembering Katherine Johnson Astronomy Cast 561: Remembering Katherine Johnson by Fraser Cain & Dr. Pamela Gay We lost a bright star here on planet Earth last week. NASA mathematician Katherine Johnson passed away at the age of 101, after an incredible career of helping humans land on the Moon. If you saw the movie Hidden Figures, you'll know what I'm talking about....


Ep. 560: Betelgeuse
560: Betelgeuse Astronomy Cast 560: Betelgeuse by Fraser Cain & Dr. Pamela Gay You might be surprised to hear that we've never done an episode of Astronomy Cast featuring Betelgeuse. Well, good news, this is that episode. Let's talk about the star, why it might be dimming, and what could happen if it explodes as a supernova....

Ep. 559: The Surface of the Sun
559: The Surface of the Sun Astronomy Cast 559: The Surface of the Sun by Fraser Cain & Dr. Pamela Gay A brand new telescope has completed on Maui's Haleakala, and it has just one job: to watch the Sun in unprecedented detail. It's called the Daniel K. Inouye telescope, and the engineering involved to get this telescope operational are matched by the incredible resolution of its first images....

Ep. 559: The Surface of the Sun
559: The Surface of the Sun Astronomy Cast 559: The Surface of the Sun by Fraser Cain & Dr. Pamela Gay A brand new telescope has completed on Maui's Haleakala, and it has just one job: to watch the Sun in unprecedented detail. It's called the Daniel K. Inouye telescope, and the engineering involved to get this telescope operational are matched by the incredible resolution of its first images....


Ep. 558: Supernova SN 2006gy
558: Supernova SN 2006gy Astronomy Cast 558: Supernova SN 2006gy by Fraser Cain & Dr. Pamela Gay We've been following this story for more than a decade, so it's great to finally have an answer to the question, why was supernova 2006gy so insanely bright? Astronomers originally thought it was an example of a supermassive star exploding, but new evidence provides an even more fascinating answer....

Ep. 557: Red Dwarfs: Friend or Foe
557: Red Dwarfs: Friend or Foe Astronomy Cast 557: Red Dwarfs: Friend or Foe by Fraser Cain & Dr. Pamela Gay On the one hand, red dwarfs are the longest lived stars in the Universe, the perfect place for life to hang out for trillions of years. On the other hand, they're tempestuous little balls of plasma, hurling out catastrophic flares that could wipe away life. Are they good or bad places to live?...

Ep. 556: Multi Messenger Astronomy
556: Multi Messenger Astronomy Astronomy Cast 556: Multi Messenger Astronomy by Fraser Cain & Dr. Pamela Gay For the longest time astronomers could only study the skies with telescopes. But then new techniques and technologies were developed to help us see in different wavelengths. Now astronomers can study objects in both visible light, neutrinos, gravitational waves and more. The era of multi-messenger astronomy is here....


Ep. 555: Satellite Constellations and the Future of Astronomy
555: Satellite Constellations and the Future of Astronomy Astronomy Cast 555: Satellite Constellations and the Future of Astronomy by Fraser Cain & Dr. Pamela Gay The other big issue at the AAS was the challenge that astronomy is going to face from all the new satellite constellations coming shortly. There are already 180 Starlinks in orbit, and thousands more are coming, not to mention the other constellations in the works. What will be the impact on astronomy, and what can we do about it?...

Ep. 554: Big Telescope Controversy in Hawai'i
554: Big Telescope Controversy in Hawai'i Astronomy Cast 554: Big Telescope Controversy in Hawai'i by Fraser Cain & Dr. Pamela Gay This week we're live at the American Astronomical Society's 235th meeting in Honolulu, Hawai'i. We learned about new planets, black holes and star formation, but the big issue hanging over the whole conference is the protests and politics over the new Thirty Meter Telescope due for construction on Mauna Kea....

Ep. 553: What To Look Forward To In 2020
553: What To Look Forward To In 2020 Astronomy Cast 553: What To Look Forward To In 2020 by Fraser Cain & Dr. Pamela Gay It's hard to believe it, but we survived another trip around the Sun. Now it's time to take the whole journey all over again, but with new news. Let's take a look at some of the space and astronomy stories we're looking forward to in 2020....


Ep. 552: Boyajian's star (and other strange stars)
552: Boyajian's star (and other strange stars) Astronomy Cast 552: Boyajian's star (and other strange stars) by Fraser Cain & Dr. Pamela Gay Huge surveys of the sky are finding more and more planets, stars and galaxies. But they're also turning up strange objects astronomers have never seen before, like Boyajian's star. Today we're going to talk about some unusual objects astronomers have discovered, and why this number is only going to go way way up....

CosmoQuest Hangoutathon Promo
Hi everyone, Producer Susie here. This weekend, December 21-23, 2019, we will be having our CosmoQuest Hangoutathon.  For 40 straight hours, our team will be bringing you guests, science and fun live on our channel. We are raising money to pay for our team to continue to bring you science, and for us to continue our citizen science programs, like the extremely successful Bennu Mappers from this past year, where over 3500 of you wonderful volunteers mapped over 14 million rocks on the asteroid Bennu, looking...

Ep. 551: Missing Epochs - Observing before the CMBR
551: Missing Epochs - Observing before the CMBR Astronomy Cast 551: Missing Epochs - Observing before the CMBR by Fraser Cain & Dr. Pamela Gay The Cosmic Microwave Background Radiation is the earliest moment in the Universe that we can see with our telescopes, just a few hundred thousand years after the Big Bang itself. What will it take for us to be able to fill in the missing gap? To see closer to the beginning of time itself?...


Ep. 550: Missing Epochs - Observing the Cosmic Dark Ages
550: Missing Epochs - Observing the Cosmic Dark Ages Astronomy Cast 550: Missing Epochs - Observing the Cosmic Dark Ages by Fraser Cain & Dr. Pamela Gay Powerful observatories like Hubble and the Very Large Telescope have pushed our vision billions of light-years into the Universe, allowing us to see further and further back in time. But there are regions which we still haven't seen: the Cosmic Dark Ages. What's it going to take to observe some of these earliest moments in the Universe?...

Ep. 549: Stellar nucleosynthesis revisited: In and on and around dead stars
549: Stellar nucleosynthesis revisited: In and on and around dead stars Astronomy Cast 549: Stellar nucleosynthesis revisited: In and on and around dead stars by Fraser Cain & Dr. Pamela Gay Last week we gave you an update on the formation of elements from the Big Bang and in main sequence stars like the Sun. This week, we wrap up with a bang, talking about the death of the most massive stars and how they seed the Universe with heavier elements....

Ep. 548: Stellar nucleosynthesis revisited: In stellar cores & atmospheres
548: Stellar nucleosynthesis revisited: In stellar cores & atmospheres Astronomy Cast 548: Stellar nucleosynthesis revisited: In stellar cores & atmospheres by Fraser Cain & Dr. Pamela Gay The Universe started out with hydrogen and helium and a few other elements, but all around us, there are other, more proton-rich elements. We believe these heavier elements formed in stars, but which stars? And at what points in their lives? Today we'll update our knowledge with the latest science....


Ep. 547: Why Astronomy Still Needs Humans
547: Why Astronomy Still Needs Humans Astronomy Cast 547: Why Astronomy Still Needs Humans by Fraser Cain & Dr. Pamela Gay Few sciences have been able to take advantage of the power of computers like astronomy. But with all this computing power, you might be surprised to learn how important a role humans still play in this science....

Ep. 546: Weird Issues: Planetary Migration
546: Weird Issues: Planetary Migration Astronomy Cast 546: Weird Issues: Planetary Migration by Fraser Cain & Dr. Pamela Gay Before we discovered other planets, our Solar System seemed like a perfectly reasonable template for everywhere. But now we see massive planets close to their stars, which leads you to the question, how does it all get there. Do the planets form in place or do they migrate around?...

Ep. 545: Weird Issues: Are comets asteroids or are asteroids comets?
545: Weird Issues: Are comets asteroids or are asteroids comets? Astronomy Cast 545: Weird Issues: Are comets asteroids or are asteroids comets? by Fraser Cain & Dr. Pamela Gay Things used to be so simple. Comets were snowballs from the outer Solar System, and asteroids were rocks from the inner Solar System. But now everything's all shades of grey. Astronomers have found asteroids that behave like comets and comets that behave like asteroids....


Ep. 544: Weird Issues: Biosignatures
544: Weird Issues: Biosignatures Astronomy Cast 544: Weird Issues: Biosignatures by Fraser Cain & Dr. Pamela Gay Once again, another place where the Universe is going to make this difficult for us. Proving, once and for all that there's alien life on another world. It should be straightforward, look for biosignatures, but it looks like there are natural sources that could explain almost any chemical we could hope to search for....

Ep. 544: Weird Issues: Biosignatures
544: Weird Issues: Biosignatures Astronomy Cast 544: Weird Issues: Biosignatures by Fraser Cain & Dr. Pamela Gay Once again, another place where the Universe is going to make this difficult for us. Proving, once and for all that there's alien life on another world. It should be straightforward, look for biosignatures, but it looks like there are natural sources that could explain almost any chemical we could hope to search for....

Halley's Meteor Shower and Two spacecraft updates
Got clear skies? Go out tonight and catch the Orionids Meteor shower, a storm of falling stars generated by Halley's comet. Later this week, we'll see aurora like those that will one day be predicted by the ESA Solar Probe. We also have an update on the Mars 2020 rover....


Ep. 543: Weird Issues: The Habitable Zone
543: Weird Issues: The Habitable Zone Astronomy Cast 543: Weird Issues: The Habitable Zone by Fraser Cain & Dr. Pamela Gay Our series on Universe weirdness marches on. This week we take a look at the habitable zone, and how things aren’t as simple as we thought....

Ep. 543: Weird Issues: The Habitable Zone
543: Weird Issues: The Habitable Zone Astronomy Cast 543: Weird Issues: The Habitable Zone by Fraser Cain & Dr. Pamela Gay Our series on Universe weirdness marches on. This week we take a look at the habitable zone, and how things aren’t as simple as we thought. In this episode we mentioned donations....

Ep. 542: Weird Issues: The Age of the Universe
542: Weird Issues: The Age of the Universe Astronomy Cast 542: Weird Issues: The Age of the Universe by Fraser Cain & Dr. Pamela Gay Our series on Universe weirdness continues, this time we learn how astronomers are struggling to make sense of the age of the Universe....


Ep. 542: Weird Issues: The Age of the Universe
542: Weird Issues: The Age of the Universe Astronomy Cast 542: Weird Issues: The Age of the Universe by Fraser Cain & Dr. Pamela Gay Our series on Universe weirdness continues, this time we learn how astronomers are struggling to make sense of the age of the Universe....

Ep. 541: Weird Issues: Expansion Rate of the Universe
541: Weird Issues: Expansion Rate of the Universe Astronomy Cast 541: Weird Issues: Expansion Rate of the Universe by Fraser Cain & Dr. Pamela Gay Just when the Universe was starting to make sense, the cosmos throws a curveball at us. Astronomers have been trying to accurately measure the expansion rate of the Universe as far back as Hubble. It's been tough to nail down, and now astronomers are starting to figure out why....

Ep. 540: Weird Issues: How Do (or Don't) Planets Form?
540: Weird Issues: How Do (or Don't) Planets Form? Astronomy Cast 540: Weird Issues: How Do (or Don't) Planets Form? by Fraser Cain & Dr. Pamela Gay As astronomers started to discover planets orbiting other stars, they immediately realized that their expectations would need to be tossed out. Hot jupiters? Pulsars with planets? We're now decades into this task, and the Universe is continuing to surprise us....


Ep. 539: Weird Issues: Why We Don't Know the Age of Saturn's Rings
539: Weird Issues: Why We Don't Know the Age of Saturn's Rings Astronomy Cast 539: Weird Issues: Why We Don't Know the Age of Saturn's Rings by Fraser Cain & Dr. Pamela Gay How old are Saturn's rings? They could be brand new, or they could be as ancient as the Solar System itself. Planetary scientists thought they knew the answer thanks to new data from Cassini, but new ideas are calling even that into question....

Ep. 539: Weird Issues: Why We Don't Know the Age of Saturn's Rings
539: Weird Issues: Why We Don't Know the Age of Saturn's Rings Astronomy Cast 539: Weird Issues: Why We Don't Know the Age of Saturn's Rings by Fraser Cain & Dr. Pamela Gay How old are Saturn's rings? They could be brand new, or they could be as ancient as the Solar System itself. Planetary scientists thought they knew the answer thanks to new data from Cassini, but new ideas are calling even that into question....

Ep. 538: Asteroids: Rubble piles of the Solar System
538: Asteroids: Rubble piles of the Solar System Astronomy Cast 538: Asteroids: Rubble piles of the Solar System by Fraser Cain & Dr. Pamela Gay Thanks to all the work from Hayabusa 2 and OSIRIS-REx, astronomers are getting a much better look at the smaller asteroids in the Solar System. It turns out, they're piles of  rubble... but fascinating piles of rubble. Let's talk about what we've learned so far....


Ep. 537: Reusable Rocket Revolution
537: Reusable Rocket Revolution Astronomy Cast 537: Reusable Rocket Revolution by Fraser Cain & Dr. Pamela Gay We took a hiatus this summer, but SpaceX sure didn’t, with the tests of the Starhopper prototype. Today we’re going to talk about the revolution in reusable rocketry and quest to build a fully reusable two-stage rocket....

Ep. 537: Reusable Rocket Revolution
537: Reusable Rocket Revolution Astronomy Cast 537: Reusable Rocket Revolution by Fraser Cain & Dr. Pamela Gay We took a hiatus this summer, but SpaceX sure didn’t, with the tests of the Starhopper prototype. Today we’re going to talk about the revolution in reusable rocketry and quest to build a fully reusable two-stage rocket....

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Astronomy Cast on Hiatus until Sept 2019
Astronomy Cast will be on hiatus for July and August. Don't worry, we'll be back in September, and we might just have surprises for you all along this summer! Don't forget you can still catch Pamela with Daily Space, rocket launches and specials on , and you can find all the space news and videos from Fraser at ! We usually record Astronomy Cast every Friday at 3:00 pm EDT / 12:00 pm PDT / 19:00 UTC. You can watch us live on here on , or the ....

Ep. 536: Everyday Relativity
536: Everyday Relativity Astronomy Cast 536: Everyday Relativity by Fraser Cain & Dr. Pamela Gay Relativity is used in more day to day situations than you may realize. In this episode, we will count (some of) the ways. This episode is brought to you live from the All-Stars Star Party in Indian Wells, California....

Ep. 535: Astronomy-Related Things To Do This Summer
535: Astronomy-Related Things To Do This Summer Astronomy Cast 535: Astronomy-Related Things To Do This Summer by Fraser Cain & Dr. Pamela Gay It's summertime, and time for our annual Astronomy Cast hiatus. But that doesn't mean that the astronomy adventure has to end. Today we'll give you some tips and tricks for astronomy summer adventures....


Ep. 534: Modern South African Astronomy
534: Modern South African Astronomy Astronomy Cast 534: Modern South African Astronomy by Fraser Cain & Dr. Pamela Gay You know the drill now. Last week we talked about ancient south African astronomy, and so this week we'll talk about the modern state of astronomy in the southern part of Africa, which happens to be a great place with nice dark skies and a perfect view into the heart of the galaxy....

Ep. 533: Indigenous South African Astronomy
533: Indigenous South African Astronomy Astronomy Cast 533: Indigenous South African Astronomy by Fraser Cain & Dr. Pamela Gay Let's move to another continent this week, and look at the astronomy that was going on in southern Africa in ancient times....

Ep. 532: Modern Astronomy of Australia
532: Modern Astronomy of Australia Astronomy Cast 532: Modern Astronomy of Australia by Fraser Cain & Dr. Pamela Gay Last week we talked about how well the indigenous Australians followed the night sky. Well, it turns out, Australia is still an amazing place for astronomy. There are so many powerful observatories in Australia, and even more in the works....


Ep. 531: Australian Indigenous Astronomy
531: Australian Indigenous Astronomy Astronomy Cast 531: Australian Indigenous Astronomy by Fraser Cain & Dr. Pamela Gay South America, especially the Atacama Desert in Chile has become one of the best places in the world to put a telescope. It's dry, high, and the nights are clear. Today we'll talk about the monster telescopes already in operation in this region, and the big ones coming soon....

Ep. 530: Astronomy of the Andes - Then and Now Pt. 2
530: Astronomy of the Andes - Then and Now Pt. 2 Astronomy Cast 530: Astronomy of the Andes - Then and Now Pt. 2 by Fraser Cain & Dr. Pamela Gay South America, especially the Atacama Desert in Chile has become one of the best places in the world to put a telescope. It's dry, high, and the nights are clear. Today we'll talk about the monster telescopes already in operation in this region, and the big ones coming soon....

Ep. 529: Astronomy of the Andes - Then and Now Pt. 1
529: Astronomy of the Andes - Then and Now Pt. 1 Astronomy Cast 529: Astronomy of the Andes - Then and Now Pt. 1 by Fraser Cain & Dr. Pamela Gay The Andes mountains in South America are a hotspot of astronomy today, but ancient peoples knew it was a great place for astronomy and lived their lives in tune with the night sky. Today we'll learn all about what they knew, and how they mapped the movements of the stars and planets....


Ep. 528: Modern Astronomy of the American Southwest
528: Modern Astronomy of the American Southwest Astronomy Cast 528: Modern Astronomy of the American Southwest by Fraser Cain & Dr. Pamela Gay Last week we talked about the ancient astronomy of the American Southwest. But this is actually Pamela's stomping grounds, and she's spent many a night perched atop mountains in this region staring in the night sky with gigantic telescopes. How does astronomy get done in this region today?...

Ep. 527: Ancient Astronomy of the American Southwest
527: Ancient Astronomy of the American Southwest Astronomy Cast 527: Ancient Astronomy of the American Southwest by Fraser Cain & Dr. Pamela Gay Ancient peoples had no light pollution, and they knew the night skies very well. In fact, they depends on them to know when to plant and when to harvest. Today Pamela talks about the archeoastronomical sites of the American Southwest....

Ep. 526: Event Horizon Telescope and the Black Hole at M87
526: Event Horizon Telescope and the Black Hole at M87 Astronomy Cast 526: Event Horizon Telescope and the Black Hole at M87 by Fraser Cain & Dr. Pamela Gay Today, of course, we're going to talk about the announcement from the Event Horizon Telescope and the first photograph of a black hole's event horizon....


Ep. 525: 100 Years of the International Astronomical Union
525: 100 Years of the International Astronomical Union Astronomy Cast 525: 100 Years of the International Astronomical Union by Fraser Cain & Dr. Pamela Gay Even though they might be scattered around our planet, astronomers have way to come together to work out issues that face their entire field of study. It's called the International Astronomical Union, and they're the ones who work out the new names for stars, and sometimes de-planet beloved Kuiper Belt Objects....

Ep. 524: Judging Age & Origins, part 3 - Beyond Our System
524: Judging Age & Origins, part 3 - Beyond Our System Astronomy Cast 524: Judging Age & Origins, part 3 - Beyond Our System by Fraser Cain & Dr. Pamela Gay We learned how to figure out the ages of objects in the Solar System, now we push out into the deeper Universe. What about stars, galaxies, and even the Universe itself? How old is it? This episode is part 3 of a series....

Ep. 523: Judging Age & Origins, Pt. 2 Across the Solar System
523: Judging Age & Origins, Pt. 2 Across the Solar System Astronomy Cast 523: Judging Age & Origins, Pt. 2 Across the Solar System by Fraser Cain & Dr. Pamela Gay Today we push our aging curiosity out into the Solar System to ask that simple question: how old is it and how do we know? What techniques do astronomers use to age various objects and regions in the Solar System? This is part two of a series....


Ep. 522: Judging Age & Origins, part 1 - Earth Rocks
522: Judging Age & Origins, part 1 - Earth Rocks Astronomy Cast 522: Judging Age & Origins, part 1 - Earth Rocks by Fraser Cain & Dr. Pamela Gay People always want to know how old everything is. And more specifically, they want to know how we know how old everything is. Well, here at Astronomy Cast, it's our job to tell you now only what we know, but how we know what we know. And today we'll begin a series on how we know how old everything is....

Bonus Episode: Dust with Dr. Paul Sutter
Bonus: Dust with Dr. Paul Sutter Astronomy Cast Bonus: Dust with Dr. Paul Sutter by Fraser Cain & Dr. Pamela Gay Recorded during the Astrotour to Costa Rica, Fraser talks to Dr. Paul Matt Sutter about the nature of dust and BICEP 2's claim of discovering primordial gravitational waves....

Ep. 521: The Deep Space Network
521: The Deep Space Network Astronomy Cast 521: The Deep Space Network by Fraser Cain & Dr. Pamela Gay We always focus on the missions, but there's an important glue that holds the whole system together. The Deep Space Network. Today we're going to talk about how this system works and how it communicates with all the spacecraft out there in the Solar System....



Ep. 516: Polar Vortices
516: Polar Vortices Astronomy Cast 516: Polar Vortices by Fraser Cain & Dr. Pamela Gay...


Ep. 513: Stellar Fusion
513: Stellar Fusion Astronomy Cast 513: Stellar Fusion by Fraser Cain & Dr. Pamela Gay...


Ep. 510: 2018 – Year in Review
2018 was an incredible year in space news. Rockets launched, landers landed, spacecraft were born and died. We learned tremendous new things about Universe around us, and today we’re here to look back fondly over the last 12 months to review the year in space that was....


Ep. 509: Fiction to Fact: 3D Printers
The technology of 3D printing is taking off. From tiny home-based 3D printers to larger manufacturing. And of course, 3D printing is going to space with the International Space Station and beyond....


Ep. 508: 2018 Holiday Gift Guide
We did it, we made it to the end of another year. Once again it’s time to wonder what gifts to get your beloved space nerds. We’ve got some suggestions. Some are brand new this year, others are classics that we just can’t help but continue to suggest....

Ep. 507: From Fiction to Fact : Ion Drive
Ion engines are a mainstay of science fiction, featured in both Star Trek and Wars. But this is a very real technology, successfully used on several missions out there in the Solar System right now. How do they work and what are the limits?...


Ep. 506: It's not Aliens, Unless it's Aliens
Did you hear that astronomers from Harvard think that the interstellar asteroid Oumuamua was actually an alien solar sail? Is it aliens? Of course it's not aliens. But some day, it'll actually be aliens....

Ep. 505: Seismology
We’re always interested in the surface features of the planets and moons in the Solar System, but that’s only skin deep. It turns out, these worlds have an interesting inner life too. Thanks to the science of seismology, we can peer into our planet and learn how it works… inside. And we’re about to take that technology to Mars....


505: Seismology
505: Seismology Astronomy Cast 505: Seismology by Fraser Cain & Dr. Pamela Gay...

Ep. 504: Radar, Lidar, and Sonar
To really study something, you want to reach out and touch it. But what can you do if you're separated by a huge distance? You reach out with electromagnetic or sound waves and watch how they bounce back. Thanks to radar, sonar and lidar....

504: Radar, Lidar & Sonar
504: Radar, Lidar & Sonar Astronomy Cast 504: Radar, Lidar & Sonar by Fraser Cain & Dr. Pamela Gay...


503: Gravity Mapping
503: Gravity Mapping Astronomy Cast 503: Gravity Mapping by Fraser Cain & Dr. Pamela Gay...

Ep. 503: Gravity Mapping
The Earth looks like a perfect sphere, but down here on the surface we see that there are mountains, rivers, oceans, glaciers, all kinds of features with different densities and shapes. Scientists can map this produce a highly detailed gravity map of our planet. And it turns out, this is very useful for other worlds too....


Ep. 502: No Touching: Determining Composition of Worlds Remotely
How do you know what something is made of if you can't reach out and touch it? How do we know what planets lights years away have in their atmosphere? What about the rocks all around Curiosity? Or the geysers coming out of Europa and Enceladus? Scientists have a few handy tricks....

501: Water Worlds Revisited
501: Water Worlds Revisited Astronomy Cast 501: Water Worlds Revisited by Fraser Cain & Dr. Pamela Gay...

Ep. 501: Water Worlds Revisited
We're not learning that the vast majority of potentially habitable worlds out there are actually icy moons like Europa and Enceladus. Good news, there are hundreds, if not thousands of times more of them than worlds like Earth. Bad news, they're locked in ice. What have we learned about water worlds and their potential for habitability?...


500: Live Celebration!
500: Live Celebration! Astronomy Cast 500: Live Celebration! by Fraser Cain & Dr. Pamela Gay...

Ep. 500: Live Celebration!
Welcome to episode 500 of Astronomy Cast. To celebrate this momentous occasion, we’re going to look back 500 years into the past to see what we learned about the Universe. And then we’re going to look 500 years into the future....


Ep. 499: What is the proposed Hubble-Lemaitre Law?
We started out Astronomy Cast with the controversal decision to de-planet Pluto. And here we are, more than a decade later, at the brink of recording our 500th episode when another big decision is coming down from the IAU: whose name goes on the concept that our Universe is expanding: Hubble or Lemaître? It's a big deal and Pamela knows all about it....

498: Dwarf Galaxy Update
498: Dwarf Galaxy Update Astronomy Cast 498: Dwarf Galaxy Update by Fraser Cain & Dr. Pamela Gay...


Ep. 498: Dwarf Galaxy Update
The Milky Way has gobbled up dozens of dwarf galaxies and added them to its structure. Today we're going to look at the ongoing hunt for the wreckage of past mergers. And what we've discovered about dwarf galaxies in general....



Ep. 495: Update on Asteroids and Prospects of Asteroid Mining
Our knowledge of space is starting to match up with our ability to get out there an explore it. There are several companies working on missions and techniques to harvest minerals from asteroids. What other resources are out there that we can use?...

494: Icy Moons Update 2018
494: Icy Moons Update 2018 Astronomy Cast 494: Icy Moons Update 2018 by Fraser Cain & Dr. Pamela Gay...


Ep. 494: Icy Moons Update 2018
Thanks to Cassini and other spacecraft, we've learned a tremendous amount about the icy worlds in the Solar System, from Jupiter's Europa to Saturn's Enceladus, to Pluto's Charon. Geysers, food for bacteria, potential oceans under the ice and more. What new things have we learned about these places?...

Ep. 493: Mars Update 2018
If there's one place we've learned more about in the last 10 years, it's Mars. Thanks to all those rovers, orbiters, landers which are flying overhead, crawling around the surface, and digging into the rich Martian regolith. What have we learned about Elon Musk's future home?...

493: Mars Update 2018
493: Mars Update 2018 Astronomy Cast 493: Mars Update 2018 by Fraser Cain & Dr. Pamela Gay...


Ep. 492: Comets, Asteroids and KBO's
Another topic with plenty of updates. Since we started Astronomy Cast we’ve visited many smaller objects in the Solar System up close, from Ceres and Vesta to Pluto, not to mention a comet. What have we learned?...

491: Exoplanet Update 2018
491: Exoplanet Update 2018 Astronomy Cast 491: Exoplanet Update 2018 by Fraser Cain & Dr. Pamela Gay...


Ep 491: Exoplanet Update 2018
Finally, a big update. Have there been news in the realm of exoplanets? More news that we can possibly cover. But we’ll try our best....

Ep 490: What's New with Supernovae
Time for another update, this time we're going to look at what's new with supernovae. And once again, we've got good news, lots of new stuff to report....


489: Black Hole Update
489: Black Hole Update Astronomy Cast 489: Black Hole Update by Fraser Cain & Dr. Pamela Gay...

Ep 489: Black Hole Update
Another update episode, this time we look at what’s new and changed in the research of black holes. And it’s here that we find a lot of substantial new discoveries in the field, so much has been discovered since we first covered black holes a decade ago....


Ep 488: Dark Energy: 2018 Edition
The updates continue. Last week we talked about dark matter, and this week we continue with its partner dark energy. Of course, they’re not really partners, unless you consider mysteriousness to be an attribute. Dark energy, that force that’s accelerating the expansion of the Universe. What have we learned?...

Ep 487: Dark Matter: 2018 Edition
Last week, we gave you an update in particle physics. This week it’s time to see what’s new in the world of dark matter. Spoiler alert, we still have no idea what it is, but maybe a few more ideas for what it isn’t....


Ep 486: Particle Physics Update
It’s time for a news update. This time from the field of particle physics. It turns out there have been all kinds of new and interesting particles discovered by the Large Hadron Collider and others. Let’s get an update from Pamela....


Ep 485: Docking, Refueling, and Transferring
It’s one thing to get to space. But once you’ve made it there, what do you want to do? You’ll probably want to dock with another space ship, deliver cargo, refuel. Today we’ll talk about how all that happens....

Ep 484: Transfer Orbits and Gravitational Assists
If you want to get around in the Solar System, you’ll want to take advantage of natural gravitational speed boosts and transfer orbits. Whether you’re heading to the outer Solar System or you want to visit the Sun itself, the planets themselves can help you in your journey....


483: Stopping in Space
483: Stopping in Space Astronomy Cast 483: Stopping in Space by Fraser Cain & Dr. Pamela Gay...

Ep 483: Stopping in Space
It’s one thing to get from Earth to space, but sometimes you want to do the opposite. You want to get into orbit or touch down gently on the surface of a planet and explore it. How do spacecraft stop? And what does that even mean when everything is orbiting?...


Ep 482: Alternative Ways to Space
Getting to space is all about rockets, but people are trying to figure out other methods that could carry payloads to orbit and beyond. Railguns, airplanes, tethers and more. Today we’ll talk about alternative methods of spaceflight....


February Q&A
This was a special Q&A episode Pamela recorded while Fraser was in Iceland....

Ep 480: Rockets pt. 2- Multi-stage Boosters
The vast majority of rockets are multi-staged affairs. Why is this? What makes this kind of rocket so successful? Today we look at the ins and outs of multi-stage rockets....



Ep. 478: Apollo 8 with Paul Hildebrandt
On Christmas Day, 1968 Frank Borman, James Lovell and William Anders became the first human being to see the far side of the Moon. Their mission, of course, was Apollo 8, the first time human beings had ever left Earth orbit and seen the far side of the Moon. Today we talk all about Apollo 8, with special guest Paul Hildebrandt, director of a new documentary about the mission....

Ep. 477: State of Exploration: Once and Future Moon
It's been decades since humans set foot on the Moon. Well, it's time to go back, in theory. Of course, we've heard this all before. What are the plans afoot to send humans back to the Moon this time. What hardware will we use, and what other strategies are in the works to make this happen?...


476: The Overview Effect
476: The Overview Effect Astronomy Cast 476: The Overview Effect by Fraser Cain & Dr. Pamela Gay...

Ep. 476: The Overview Effect
After they’ve been to space, many astronauts report that seeing the world from above has given them a totally new perspective on humanity and the state of our planet. It’s called the Overview Effect. Today we’ll talk about this, and what this perspective can teach us all....

475: Fast Radio Bursts
475: Fast Radio Bursts Astronomy Cast 475: Fast Radio Bursts by Fraser Cain & Dr. Pamela Gay...


Updated audio - Ep. 475: Fast Radio Bursts
You know what's fun? Mysteries. Here's one: fast radio bursts. Astronomers have been detecting mysterious one-time signals from across the sky. What's causing them? Nobody knows for sure, but the search is on to get to the bottom of them....

Ep. 475: Fast Radio Bursts
You know what's fun? Mysteries. Here's one: fast radio bursts. Astronomers have been detecting mysterious one-time signals from across the sky. What's causing them? Nobody knows for sure, but the search is on to get to the bottom of them....

474: Predictions for 2018
474: Predictions for 2018 Astronomy Cast 474: Predictions for 2018 by Fraser Cain & Dr. Pamela Gay...


Ep. 474: Predictions for 2018
Phew, 2018, time to press the reset button and enjoy a whole new year of space exploration and space science. What’s coming up this year? What should we expect to launch, and what will we see in the sky?...

Ep. 473: Remembering the Best Space Science of 2017
2017 was a crazy year for, well, you know. But, it was a great year for space science, a kilonova, extrasolar planets, reusable rockets and more. Let’s look back at the year that was and remember our favorite space science....





Ep. 468: Simulations for Science and Fun
Astronomers depend on simulations to study the Universe. From relatively straightforward orbital simulations to vast simulations that try to recreate the large scale structure of the Universe from the Big Bang. Today we're going to talk about some of those simulations, as well as tools you can use simulate the Universe....

467: Resonance
467: Resonance Astronomy Cast 467: Resonance by Fraser Cain & Dr. Pamela Gay...

466: Origins of Zero (0)
466: Origins of Zero (0) Astronomy Cast 466: Origins of Zero (0) by Fraser Cain & Dr. Pamela Gay...


Ep. 467: Resonance
Many of the moons and planets across the Universe are in resonance with each other and their star. What causes this resonance, and how can it help us understand the history of planetary formation and migration?...

Ep. 466: Origins of Zero (0)
We depend on zero for our math to work right, but this number was actually invented in fairly recent times. Why do we need zero? Was it inevitable?...


Ep. 465: Exploiting Interfering Light
Electromagnetic radiation, also known as “light” is pretty handy for astronomers. They can use it to directly and indirectly observe stars, nebula, planets and more. But as you probably know, light can act like a wave, creating interference patterns to teach us even more about the Universe....

Ep. 464: Why the Hype over an Exorock?
Astronomers this week announced that they had discovered an asteroid or comet on a trajectory that brought it from outside the Solar System? Is this the first case of an object from deep space? And what can we learn from this discovery?...


Ep. 463: Pareidolia and the Moon
The man in the moon, the pyramids on Mars. Every cloud, ever. Humans have a tendency to pattern match when they're looking around the Universe - it's called pareidolia. What causes this behaviour, and how can we use this to debunk some hilarious conspiracy theories?...

462: Modeling the Weather
462: Modeling the Weather Astronomy Cast 462: Modeling the Weather by Fraser Cain & Dr. Pamela Gay...


Ep. 462: Modeling the Weather
Have you noticed that weather forecasting has gotten much better in the last few years? Thanks to weather satellites, weather stations, and better forecasting techniques. How do scientists predict the weather with any kind of accuracy days or even weeks in the future....

Ep. 461: Measuring the Weather with Satellites
What’s the weather doing? Is it going to rain today? How much? What about temperatures? We depend on modern weather forecasting, thanks, in part to the vast network of weather satellites. What instruments do they have, what orbits do they use....


Ep. 460: Earth from Afar: Remote Sensing
The space age has given us the ability to look at every corner of the globe in every wavelength. It’s revolutionized our ability to predict the weather, keep track of environmental damage, and watch the world change. Today we look at what missions and technologies give us the ability to watch our world from afar....

459: Arecibo Observatory
459: Arecibo Observatory Astronomy Cast 459: Arecibo Observatory by Fraser Cain & Dr. Pamela Gay...


Ep. 459: Arecibo Observatory
And now Cassini’s gone. Smashed up in the atmosphere of Saturn. But planetary scientists are going to be picking through all those pictures and data for decades. Let’s look back at some of the science gathered up by Cassini so far, and we can still learn from this epic journey....

458: The Science of Cassini
458: The Science of Cassini Astronomy Cast 458: The Science of Cassini by Fraser Cain & Dr. Pamela Gay...

Ep. 458: The Science of Cassini
And now Cassini’s gone. Smashed up in the atmosphere of Saturn. But planetary scientists are going to be picking through all those pictures and data for decades. Let’s look back at some of the science gathered up by Cassini so far, and we can still learn from this epic journey....


Ep. 457: Why Did Cassini Have To Die? In Memoriam
It's time to say goodbye to an old friend, NASA's Cassini spacecraft, which has been orbiting within the Saturnian system since 2004. But why does a seemingly healthy spacecraft and mission need to come to an end? Today we look back at the mission, some of the amazing discoveries, and why its finale was necessary....

456: Pluto Revisited
456: Pluto Revisited Astronomy Cast 456: Pluto Revisited by Fraser Cain & Dr. Pamela Gay...


Ep. 456: Pluto Revisited
This week, we return to our starting point, where Astronomy Cast began: Pluto. 11 years on, we have a whole new appreciate for the dwarf planet Pluto. We’ve visited it, probed it and taken pictures. It’s time for an update....


Astronomy Cast Extra: Solar Eclipse 101
This episode was recorded live in St. Louis, MO at the Astronomy Cast Solar Eclipse Escape 2017. We're going to give you a set of last minute tips and info to prepare for the Great American Eclipse!...

Astronomy Cast Extra! Solar Eclipse 101
Pamela and Fraser talk about solar eclipse basics at their Solar Eclipse Escape event in Saint Louis on August 19th. What to do, and (perhaps more importantly) what NOT to do is covered!...


Ep. 454: Things We're Looking Forward To
As we wrap up season 10 of Astronomy Cast, we look forward to all the instruments, missions and science results on the distant horizon. Think astronomy is exciting already? Just you wait....


Ep. 452: Summer Observing Challenges
Summer is almost here, and for the northern hemisphere, that means warm nights for observing. But what to observe? We're here with a list of events and targets for you to enjoy over the summer. Get your calendars handy, and start organizing some events with your friends, and then get out there!...

Ep. 451: When Can I Buy My Ticket To Space?
Like most of us, you probably want to know what it would be like to travel to space. Maybe not to live, but just to visit. You want to be a space tourist. Good news, there are a bunch of companies working hard to give you the opportunity to fly to space. How long until you can buy a ticket?...


450: Inflatable Habitats
450: Inflatable Habitats Astronomy Cast 450: Inflatable Habitats by Fraser Cain & Dr. Pamela Gay...

Ep. 450: Inflatable Habitats
In order to live in space, we'll need to live in a habitat that simulates the temperature, pressure and atmosphere of Earth. And one of the most interesting ideas for how to do this will be with inflatable habitats. In fact, there are a few habitats in the works right now, including one attached to the International Space Station....


449: Robots in Space!
449: Robots in Space! Astronomy Cast 449: Robots in Space! by Fraser Cain & Dr. Pamela Gay...

Ep. 449: Robots in Space!
When you think of a robot, you’re probably imagining some kind of human-shaped machine. And until now, the robotic spacecraft we’ve sent out into space to help us explore the Solar System look nothing like that. But that vision of robots is coming back, thanks to a few new robots in development by NASA and other groups....


Ep. 448: Prepping for the Eclipse
On Monday, August 21, 2017, there’s going to be a total eclipse of the Sun, visible to path that goes right through the middle of the United States. You should be making plans to see this, and we’re here to help you know where to go and what to do....



Ep. 445: Animals in Space Pt. 1: Insects and Arachnids
We've talked about animals traveling to space in the past, but it's time to take another look, with many other creatures making the trip to the void. Today we're going to talk about the spineless insects and arthropods, and those tough as nails waterbears – tardigrades....

444: Fractals
444: Fractals Astronomy Cast 444: Fractals by Fraser Cain & Dr. Pamela Gay...

Ep. 444: Fractals
For this historic 444th episode of Astronomy Cast, we talk about fractals. Those amazing mathematical visualizations of recursive algorithms. What are they, how do you get them? Why are they important?...


Ep. 443: Destroy and Rebuild Pt. 7: Tsunamis
Surf’s up! Today we’re going to be talking about one of the most devastating natural disasters out there: tsunamis. We’re talking huge waves that wreck the seashore. But it turns out, there many ways you can get a tsunami, and one of those has to do with space....

Ep. 442: Destroy and Rebuild Pt. 6: Magnetic Pole Reversal
If we look back into the geologic record of the Earth, it appears that our planet’s magnetic field flips polarity every few hundred thousand years or so. Why does this happen? When’s it supposed to happen next? Is it dangerous?...



Ep. 440: Destroy and Rebuild, Pt. 4: Supervolcanoes!
There are regular volcanoes, and then there are the supervolcanoes. Massive calderas of hot magma of incomprehensible size. Bad news, these things explode randomly and catastrophically. Worse news, there are a bunch around the Earth....


Ep. 439: Destroy and Rebuild, Pt. 3: How Do We Terraform Earth?
We always want to talk about how we can make Mars more Earth like, but the reality is that we’re making Earth more Venus-Like. We’re Venusforming Earth. What are the various factors we’re impacting on a global scale, and how can we fix them?...

Ep. 438: Destroy and Rebuild, Pt. 2: Geoengineering
We know humans are having an impact on planet Earth, but what if we really put our backs into it, and intentionally tried to change the entire planet? Either to make it better, or to fix some terrible mistake we've made. The technique is called geoengineering. Could it work?...


Ep. 437: Destroy and Rebuild, Pt. 1: The Torino Scale
We love to destroy the universe, and also rebuild it. Today we begin a new series where we destroy and rebuild. Let's talk about some existential threats we face, and ways we could recover, starting with the sword of Damocles hanging over our head: killer asteroids!...

436 Bonus: Moon Cheeziness
436 Bonus: Moon Cheeziness Astronomy Cast 436 Bonus: Moon Cheeziness by Fraser Cain & Dr. Pamela Gay...


Ep. 436: Common Misconceptions in Probability
Human beings are bad at many things, but we're particularly terrible at understanding probability in a rational way. We underestimate, overestimate and generally mess up probability. We'll try to fix it here, but we'll surely fail....

Ep. 435: The Butterfly Effect
Small changes can have a big impact. But can a butterfly’s wingbeat in the Amazon really impact the weather halfway across the world? And where do small changes have no impact?...


435: The Butterfly Effect
435: The Butterfly Effect Astronomy Cast 435: The Butterfly Effect by Fraser Cain & Dr. Pamela Gay...

Ep. 434: Am I On An Alien World?
Once again, science fiction television and movies has let you down. They try to recreate what it might be like on an alien world, but surprise surprise, they mostly get it wrong. That’s because a truly alien world would be different in so many ways, it would blow your mind. Today we’ll help you figure out if you’re on a movie set, or you’ve actually crashlanded on an alien planet....


433: Volcanoes on Mars
433: Volcanoes on Mars Astronomy Cast 433: Volcanoes on Mars by Fraser Cain & Dr. Pamela Gay...

Ep. 433: Volcanoes on Mars
Mars is a world of extremes. This unassuming red world is home to the largest and tallest volcanoes in the entire Solar System. In fact, it’s not even a close contest, with Olympus Mons rising 22 km above the surrounding plains, more than twice as tall as Mount Everest. How did Mars get such big volcanoes, and how active is the planet today?...


Ep. 432: Geoglogic Ages of Mars - From Wet and Wild to Desolate Desert
Today, Mars is a desolate wasteland, with dusty red rocks and sand stretching out to the horizon. But billions of years ago, it was a vastly different world. It was blue, with oceans, rivers, lakes, and maybe life? Let’s tell the story of geology on Mars, and we got from that world to the one we see today....

Ep. 431: The Search for Life on Mars
Enceladus and Europa are all the rage these days, but classic Mars is still a great place to search for life. In fact, ESA’s ExoMars is scanning the planet’s atmosphere for methane, evidence that there might be life there right now. Let’s talk about the search for life on the Red Planet....


430: Coming Home from Mars
430: Coming Home from Mars Astronomy Cast 430: Coming Home from Mars by Fraser Cain & Dr. Pamela Gay...

Ep. 430: Coming Home from Mars
Landing on the surface of Mars is very difficult. In fact, it’s probably the toughest planet to land on in the whole Solar System. Today we’ll talk about what it’s going to take to get to and return from Mars!...

Ep. 429: Living on Mars
When Elon Musk announced plans to send humans to Mars, he conveniently left out one important aspect. How are we supposed to survive on a place this hostile to life? Seriously, Mars sucks, and it's going to take some impressive techniques and technologies to make it on the Red Planet....


429: Living on Mars
429: Living on Mars Astronomy Cast 429: Living on Mars by Fraser Cain & Dr. Pamela Gay...

Ep. 428: The Moons of Mars
We begin a miniseries on Mars. How many episodes will we do? Who knows? But we start today with a discussion of the two Mars moons, Phobos and Deimos....

428: The Moons of Mars
428: The Moons of Mars Astronomy Cast 428: The Moons of Mars by Fraser Cain & Dr. Pamela Gay...


Ep. 427: Click Bait vs Clear Science
Did you hear that Dark Energy doesn't exist any more? Neither does Dark Matter? It turns out that NASA recalculated the Zodiac and now you're an Ophiuchan! Science is hard enough, but communicating that science out to the public when there are publications hungry for traffic is even harder! Here's how to parse the click-bait science titles....

426: Confirmation Bias
426: Confirmation Bias Astronomy Cast 426: Confirmation Bias by Fraser Cain & Dr. Pamela Gay...


Ep. 426: Confirmation Bias
I hate to tell you this, but that meat computer in your skull is constantly betraying you. Don’t worry, we’ve all got the same, but fortunately, scientists have learned how this happens, and can help us make sure our science, and lives don’t suffer because of it....

Ep. 425: Naming Spacecraft
Have you ever noticed spacecraft missions have some pretty cool names? How does anyone decide what to call these things?...

425: Naming Spacecraft
425: Naming Spacecraft Astronomy Cast 425: Naming Spacecraft by Fraser Cain & Dr. Pamela Gay...


424: Lightning
424: Lightning Astronomy Cast 424: Lightning by Fraser Cain & Dr. Pamela Gay...

Ep. 424: Lightning
It turns out that nature figured out how to use electricity long before humans did. Lightning storms are common across the Earth, and even the Solar System. What causes this electricity in the sky, and how can science use it?...

Ep. 423: Cyclones
As Hurricane Matthew reminded us, cyclonic storms are a force to be reckoned with. What causes these storms, and how can they form across the Solar System....


423: Cyclones
423: Cyclones Astronomy Cast 423: Cyclones by Fraser Cain & Dr. Pamela Gay...

Ep. 422: Geysers
So if you’ve been to Yellowstone National Park, you’ve seen one of the most amazing features of the natural world – geysers. In today’s episode, we’re going to talk about geysers on Earth, and where they might be in the solar system....

422: Geysers
Astronomy Cast 422: Geysers by Fraser Cain & Dr. Pamela Gay...


421: Space Games!
Astronomy Cast 421: Space Games! by Fraser Cain & Dr. Pamela Gay...

Ep. 421: Space Games!
As you probably know, Fraser is an avid video gamer, especially if it has anything to do with space. Today we turn things around, as Fraser talks about the games he plays, and what he thinks you should be playing too....

420: FIRE!
Astronomy Cast 420: FIRE! by Fraser Cain & Dr. Pamela Gay...


Ep. 420: FIRE!
One of the most dangerous things that can happen inside a spacecraft is fire. Seriously, it’s NASA’s worst nightmare, and for good reason. Fire acts differently in space, and astronauts are always on alert. Here’s why....

Ep. 419: DragonCon 2016 Live - Rocket Girls
This episode is a special live show that took place at DragonCon 2016 in Atlanta, GA. Pamela hosted a panel of amazing scientists and engineers who all happen to be women, and they discussed the unsung women of NASA and the early Space Age and their roles as “human computers”, and the current climate at JPL for women scientists and engineers....


418: I'm a Teapot
AstronomyCast 418: I'm a Teapot by Fraser Cain & Dr. Pamela Gay...

Ep. 418: Error 418 – I’m a Teapot!
One of the most familiar asterisms in the night sky is the Teapot, in Sagittarius. Today we’re going to talk about that and have a bonus conversation about Bertrand Russell’s Teapot Argument....


Ep. 417: Error 417: Expectation Failed
In all fields of science, sometimes more is learned when you fail at what you’re trying to do than when you succeed. So what new science discoveries have failed expectations given us in astronomy?...

Ep. 416: Fireballs from the Sky!
Every now and then we look up and see bright fiery balls falling from the sky. Don’t panic, these are just bolides. Sometimes they leave trails, sometimes they explode, and sometimes they survive all the way to the ground....


Ep. 415: Temperature of the Universe
The temperature of the Universe can vary a dramatic amount from the hot cores of stars to the vast cold emptiness of deep space. What’s the temperature of the Universe now, and what will it be in the future?...


Ep. 414: Navigating Far
In our last episode, we talked about what it’ll take to navigate across the Solar System. In this episode we scale things up and speculate how future civilizations will navigate to other stars and even other galaxies....

Ep. 413: Navigating Near
It’s hard enough finding your way around planet Earth, but what do you do when you’re trying to find your way around the Solar System? Today we’ll talk about how spacecraft navigate from world to world....


Ep. 412: The Color of the Universe
What color is the Universe? Turns out this isn’t a simple question, and one that scientists have really been unable to answer, until now!...


Ep. 411: Science of Sunset Colors
We all enjoy beautiful, multicolored sunsets. But what causes the brilliant oranges, pinks and purples that we see, and why does it change from day to day and season to season?...


Ep. 410: Planet 9 Facts and Fiction
The discovery of Planet 9 has caused a wonderful, confusing uproar and a flood of misinformation in the news and social media. We’ll sort out what we actually know, what things just aren’t true, and what things might be possible!...

Ep. 409: Spin in the Universe
The Solar System is a spinny place. Everything’s turning turning. But if you look closely, there are some pretty strange spins going on. Today we talk about how everything started turning, and the factors that still “impact” them today....


Ep. 408: Universe Cannibalism
We’ve talked about stellar cannibalism and galactic cannibalism, but now it’s time to take this concept to its logical extreme – universe cannibalism. In the multiverse theory of physics we live in just one of a vast range of universes which might interact with each other. Let’s look for the evidence....


Ep. 407: Galactic Cannibalism
Remember when we told you that the Universe is a big place, and anything that can go wrong, inevitably does? Today we talk about what happens when galaxies come together. This is particularly pertinent because our Milky Way will collide with Andromeda in the future!...

Ep. 406: Stellar Cannibalism
Most of the time stars hang around for billions of years. But the Universe is a big place, and anything that can go wrong, inevitably does. Today we talk about what happens when these stars come together. The outcome is violent, and fortunately for you, also interesting....


Ep. 405: Method Not Found
Last week we talked about knowledge, what we do and don’t know. This week we talk about questions which are impossible to ask, where the answers don’t actually exist....




Ep. 401: Future Predictions
What do Pamela and Fraser think will happen or be discovered in 2016? What would they like to see in the near future?...

Ep. 400: The State of the Universe
It’s time for us to go back and catch up with all of the projects, news stories, weird star systems, and other topics that need updating!...


Ep. 399: Women in Science
Science is typically a male dominated profession, mostly dudes, not a lot of ladies. From researchers to professors, to law makers, woman have a tough time gaining traction in such a heavily gendered field. Today we’re going to talk about what it takes to make it as a woman in science, what additional hurdles you’ll have to navigate, and what resources are available if you’re being harassed or discriminated against....

Ep. 398: Seeing Things: Emitting, Reflecting, Ionizing Light
Astronomers gather electromagnetic radiation with the telescopes: mostly visible light. But sometimes they've got to be clever about where they look for these elusive photons. Light can get emitted, absorbed, reflected, and each method tells astronomers a little more about what they're looking at....


Ep. 397: A Universe From Nothing
One of the biggest, most basic questions you can ask is: “why is there something and not nothing?” The reality is that we don’t know the answer, we might never know the answer. Today we’ll investigate this mystery, recently covered by the physicist Lawrence Krauss in his book of the same name....


Ep. 396: Family Astronomy for the Holidays
Every year, it’s the same dilemma: what gift should you get for the super space nerd in the family? And if someone has a budding interest in space and astronomy, what can you do to feed their hunger for knowledge? Today we’ll talk telescopes, books and planispheres. Everything you need to avoid a holiday gift disaster....

Ep. 395: Baryons and Beyond the Standard Model
In the last few episodes, we’ve been talking about the standard model of physics, explaining what everything is made up of. But the reality is that we probably don’t know a fraction of how everything is put together. This week we’re going to talk about baryons, the particles made up of quarks. The most famous ones are the proton and the neutron, but that’s just the tip of the baryonic iceberg. And then we’re going to talk about where the standard model ends, and what’s next in particle physics....


Ep. 394: The Standard Model - Bosons
All fundamental particles are either fermions or bosons. Last week we talked about quarks, which are fermions. This week we’ll talk about bosons, including the famous Higgs boson, recently confirmed by the Large Hadron Collider....

394: Bosons
AstronomyCast 394: Bosons by Fraser Cain & Dr. Pamela Gay...

Ep. 393: The Standard Model, Leptons and Quarks
Physicists are getting a handle on the structure of the Universe, how everything is made of something else. Molecules are made of atoms, atoms are made of protons, neutrons and electrons, etc. Even smaller than that are the quarks and the leptons, which seem to be the basic building blocks of all matter....


Ep. 392: The Standard Model - Intro
Humans, cars and planets are made of molecules. And molecules are made of atoms. Atoms are made of protons, neutrons and electrons. What are they made of? This is the standard model of particle physics, which explains how everything is put together and the forces that mediate all those particles....


Ep. 391: Entrophy
Have you ever been doing thermodynamics in a closed system and noticed that there’s a finite number of ways that things can be arranged, and they tend towards disorder? Of course you have, we all have. That’s entropy. And here in our Universe, entropy is on the rise. Let’s learn about entropy in its specific, thermodynamic ways, and then figure out what this means for the future of the Universe....

391: Entropy
AstronomyCast 391: Entropy by Fraser Cain & Dr. Pamela Gay...


Ep. 390: Occam’s Razor and the Problem with Probabilities
I’m not saying it’s aliens, but it’s aliens. Actually, it’s almost certainly not aliens, or a wormhole, or a multiverse. When scientists discover something unusual, they make guesses about what’s happening. But Occam’s Razor encourages us to consider the probabilities of different events before making any concrete predictions....

Ep. 389: Roundtable with Paul Sutter
While Pamela and Fraser were at Ohio State University for a symposium in October, they caught up with Paul M. Sutter from Astronomical Observatory of Trieste, who is a visiting scholar at the OSU Center for Cosmology and Astro-Particle Physics. His specialty is cosmic voids. Paul also hosts the podcast “Ask a Spaceman.”...


Ep. 388: Megastructures
This week astronomers announced an unusual transit signal from another star. Although it’s most likely a natural phenomenon, one remote possibility is that this is some kind of alien megastructure. Freeman Dyson and others have considered this idea for decades. Today we’ll talk about the kinds of structures that aliens might want to build....


Ep. 387: Water on Mars… Again
Have you heard the big news? NASA has reported that Mark Watney is alive and well on the surface of Mars. No, wait, they’ve reported that there’s water on Mars. Didn’t they already report this? Today we’ll update you on the latest discovery and what this means for the search for life on Mars....

Ep. 386: Orbiting Observers
The atmosphere keeps us alive and breathing, but it really sucks for astronomy. Fortunately, humanity has built and launched space telescopes that get above the pesky atmosphere, where the skies are really clear. Let’s take a look at the past, current and future of orbital observation....


Ep. 385: Rovers on the Run
Taking pictures of distant worlds is great and all, but the best science happens with boots on the ground. Or in this case... wheels. This week we'll talk all about robotic rovers and the places they rove....

Ep. 384: Escaping Probes
The gravity of the Earth is a tough thing to escape, but breaking free from the gravity of the Sun is on a whole other level. But humans have achieved this amazing accomplishment, and right now there are several spacecraft leaving the Solar System and never coming back....


Ep. 383: Approaches to Absolute Zero
The coldest possible theoretical temperature is Absolute Zero, this is the point at which no further energy can be extracted from a system. How are physicists working to get as close as possible to this extreme cold?...


Ep. 382: Degenerate Matter
In some of the most extreme objects in the Universe, white dwarfs and neutron stars, matter gets strange, transforming into a material that physicists call “degenerate matter”. Let’s learn what it is, how it forms....

Ep. 381: Hollowing Asteroids in Science and Fiction
When we finally make the jump to fully colonizing the Solar System, we're going to want to use asteroids as stepping stones. We can use them as way stations, research facilities, even as spacecraft to further explore the Solar System. Today we'll talk about the science and science fiction of hollowing out asteroids....