Every two years or so, Mars lines up nicely with the Earth. It only takes two minutes to communicate with rovers, you can see the polar ice caps in a small telescope, and it’s the best time to send spacecraft to the red planet.
Our Hosts
Fraser Cain
Universe Today
Dr. Pamela Gay
CosmoQuest
Production by
- Richard Drumm, Audio Engineer
- Ally Pelphrey, Video Engineer
17 Seasons
700+ Episodes
2018 Winner Parsec Award
Ep. 576: Summer Stargazing Special
It’s time, once again, for Astronomy Cast to go on hiatus. You’ve got a couple of months on your own to explore the night sky. Before we say goodbye, though, we’d like to make a few suggestions.
Ep. 575: Observing the Moon
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?
Ep. 574: Trojan Asteroids
We imagine the asteroid belt as the place where all the rocks hang out in the Solar System, but there are two huge bands of asteroids that orbit the Sun with Jupiter called the Trojans. And soon, we might actually get a chance to see them up close.
Recent Episodes
Ep. 23: Counting Aliens With the Drake Equation
If you're wondering how many extraterrestrials there are in our galaxy, you just have to use a simple equation developed by astronomer Frank Drake in 1961. Just find out how many stars there are, how many support life, how many advanced societies form, and a few other...
Ep. 22: Variable Stars
Our Sun has been around for billions of years, and will last for billions more. We're lucky, it's pretty stable and regular as stars go, only changing in brightness a little now and then. But there are stars out there that change dramatically; astronomers call them...
Ep. 21: Questions Show #2
Our episode on black holes generated many many questions from listeners. We dip into this bottomless pool of questions and start dealing with them. Are really big black holes like the Big Bang? How can black holes evaporate? What would it look like to stand on a black...
Ep. 20: What We Learned from the American Astronomical Society
It's astronomical society get together time, and we send Pamela to investigate and record. Hear the latest news that will make your text books out of date. Find out where all the dark matter is collecting, the identity of Kepler's supernova, and new insights into the...
Ep. 19: Comets, Our Icy Friends from the Outer Solar System
The sudden brightening of Comet McNaught has reminded us what a treat it can be to see a comet with the unaided eye. A diffuse ball with a long tail stretching across the sky. There's nothing else in the night sky that can compare to a bright comet. But what are these...
Special Alert: Go See Comet McNaught
There's a big bright comet visible in the sky right now. Listen to this special alert, and then go outside right at sunset to see Comet McNaught with your very own eyes. You've got to move quickly, as it'll be lost in the glare of the Sun. Don't worry, it'll reappear...
Ep. 18: Black Holes Big and Small
We're finally ready to deal with the topic you've all been waiting for: Schwarzschild swirlers, Chandrasekhar crushers, ol' matter manglers, sucking singularities... you might know them as black holes. Join as as we examine how black holes form, what they consume, and...
Ep. 17: Where does the Moon Come From?
We take the Moon for granted, but its effect on the Earth is very important; possibly even critical for the formation of life. But where did it come from? Did the Earth and Moon form together? Or did the Earth capture a wayward Moon? Or was there a more catastrophic...
Ep. 16: Across the Electromagnetic Spectrum
We see the Universe in visible light with our photon detecting eyes. We can feel infrared heat with our photon detecting hands, and we get sunburns with our ultraviolet photon detecting skin (ouch). But there's a whole spectrum of photons out there, from radio waves...
Ep. 15: Questions Show #1
We finally get organized enough deal with several listener questions: isn't dark matter just regular stuff we can't see? how can parts of the Universe be expanding faster than the speed of light? what will Betelgeuse look like when it explodes as a supernova? what's...
Ep. 14: We're all Made of Supernovae
No more suspense. This week we blow the biggest stars up. Kaboom. Want more details? Then you've got to listen. Download Episode 14: We're all Made of Supernovae (12.3 MB) Jump to Shownotes Jump to Transcript or Download (coming soon!) Shownotes Transcript: We're All...
Ep. 13: Where Do Stars Go When They Die?
We've celebrated the birth of new stars, but the stellar lifecycle doesn't end there. Stars like our Sun will spend billions of years fusing together hydrogen and pumping out energy. And when the fuel runs out, their death is as interesting as their birth. This week...
Ep. 12: Where Do Baby Stars Come From?
Most parents have had that uncomfortable conversation with their children at some point. Mommy, Daddy, where do stars come from? You hem and haw, mumble a few words about angular momentum and primordial hydrogen and then cleverly change the subject. Well, you don't...
Ep. 11: A Universe of Dark Energy
The discovery of dark energy was one of the biggest surprises in astronomy. Instead of a nice, predictable expanding Universe, acted on only by gravity, astronomers turned up a mysterious repulsive force accelerating the expansion of the Universe. Fraser and Pamela...
iPod Issues Fix
Several of you have reported problems getting your iPods to play our show and other podcasts. Unfortunately, the latest version of iTunes has some new features that are making iPods behave oddly when they try to play podcasts that aren't in stereo. To fix this...
Ep. 10: Measuring Distance in the Universe
You hear distances all the time in astronomy. This star is 10 light-years away; that galaxy is 50 million light-years away; that Big Bang over there happened 13.7 billion years ago. But how did astronomers actually figure out how far away everything is? It's not a...
Ep. 9: Einstein's Theory of Special Relativity
It's all relative. How many times have you heard that? Well, when you're traveling close to the speed of light, everything really is relative; especially the passage of time. This week, Fraser and Pamela give you the skinny on Einstein's Special Theory of Relativity....
Ep. 8: Meteor Showers. Yes, the sky is falling.
Dress warmly, gather some friends and family, and head outside to watch sand burn in the upper atmosphere. There's nothing like a good meteor shower. Fraser and Pamela explain this beautiful phenomenon: what causes them, the best storms and showers to watch for, and...
Ep. 7: Getting Started in Amateur Astronomy
Got your eye on that $40 telescope at Walmart? Wait, hear us out first! Fraser and Pamela discuss strategies for getting into amateur astronomy - one of the most worthwhile hobbies out there. We discuss what gear to get, where to look, and how to meet up with other...
Ep. 6: More Evidence for the Big Bang
Last week's episode started out with a bang... a Big Bang. This week we continue our discussion into the beginning of everything. We present three additional lines of evidence that have led astronomers to the conclusion that our Universe started out as a singularity...