A rock is a rock is a rock, right? Across the Solar System there are giant rocky asteroids and even rockier moons. What’s the difference between these two families of objects, and where did they come from?
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Fraser Cain
Universe Today
Dr. Pamela Gay
CosmoQuest
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18 Seasons
700+ Episodes
2018 Winner Parsec Award
Ep. 621: Gas Giants
For the longest time, the only gas giant planets we knew about were Jupiter and Saturn. But now in the age of extrasolar planets, astronomers have discovered thousands of gas giants across almost as many star systems. What new discoveries have been made about gas giants, both here in the Solar System and across the Milky Way?
Ep. 620: Why Getting to the Outer Worlds is So Difficult
Good news! Over the next few years, we’re going to see a flotilla of new missions headed to Jupiter and Saturn. Why aren’t we seeing more missions to the outer planets, like Uranus and Neptune? It turns out, those places are far away. Today let’s talk about the challenge of exploring the outer Solar System.
Ep. 619: Icy Moons and Dwarf Planets
The outer Solar System is far enough from the Sun that water doesn’t get blasted away into deep space. In this icy realm, there are many worlds with vast quantities of water ice. Today let’s look at the icy outer moons and dwarf planets.
Recent Episodes
Ep. 108: The Life of the Sun
We've talked about the Sun before, but this time we're going to look at the entire life cycle of the Sun, and all the stages it's going to go through: solar nebula, protostar, main sequence, red giant, white dwarf, and more. Want to know what the future holds for the...
Questions Show – light speed, Andromeda galaxy, dark matter and black holes
Another week, another roundup of your questions. This week listeners asked: will reaching light speed destroy the Universe? When is Andromeda going to look really, really cool with the unaided eye? Why didn't dark matter all turn into black holes? And there's even...
Ep. 107: Nucleosynthesis: Elements from Stars
Look around you. Breathe in some air. Everything you can see and feel was formed in a star. Today we'll examine that long journey that matter has gone through, forged and re-forged in the hearts of stars. In fact, the device you're using to listen to this podcast has...
Questions Show – Black Hole Surfaces, Magnetic Field Strengths, and the Speed of Gravitons
As you know, we wanted to answer listener questions regularly, but we found it was taking away from the regular weekly episodes of Astronomy Cast. So we've decided to just split it up and run the question shows separately from the regular Astronomy Cast episodes. If...
Ep. 106: The Search for the Theory of Everything
At the earliest moments of the Universe, there were no separate forces, energy or matter. It was all just the same stuff. And then the different forces froze out, differentiating into electromagnetism, the strong force and the weak force. Today we'll look at the...
Student Questions Show: Leelanau School
This is our forth installment in our series of student questions shows and these questions come to us from Leelanau High School. Thanks to GLAST, Astronomy Cast is now able to provide equipment to send to high school teachers who want to Pamela and Fraser to do a...
Ep. 105: The Strong and Weak Nuclear Forces
After a quick Dragon*Con break, we're back to our tour through the fundamental forces of the Universe. We've covered gravity and electromagnetism, and now we're moving onto the strong and weak nuclear forces. We didn't think they'd really need to be separate episodes,...
Ep 104: Science Fiction at Dragon*Con with Plait and Grazier
Pamela left Fraser behind (with sorrow) and took on Dragon*Con and the facts (or lack there of) in Science Fiction. Helping her out were special guests Phil Plait and Kevin Grazier. Ep. 104: Science Fiction at Dragon*Con with Plait and Grazier Jump to Shownotes Jump...
Ep. 103: Electromagnetism
Our series on the basic forces of the cosmos continues! Last week we discussed gravity, and this we'll handle electromagnetism. Electricity and magnetism are just two aspects of the same force, and you can't talk about astronomy without understanding these two keys...
Ep 102: Gravity
You seem to like a nice series, so here's a new one we've been thinking about. Over the course of the next 4 weeks, we're going to cover each of the basic forces in the Universe. And this week, we're going to start with gravity; the force you're most familiar with....
Ep. 101: Advanced Propulsion Systems
Last week we talked about rockets. How they work and their limitations. This week we're going to look at the future of propulsion systems. From the ion engines that are already working to explore the Solar System to the prototype solar sails to futuristic technologies...
Ep. 100: Rockets
To move around in space, you need some kind of propulsion system. And for now, that means rockets. Let's learn the underlying science of rockets, and how they work. And learn why a rocket will never let us reach the speed of light. Ep. 100: Rockets Jump to Shownotes...
Ep. 99: The Milky Way
The Milky Way is our home. An island of stars in a universe of other galaxies. But you might be surprised to learn that astronomers have only known the Milky Way's true nature for just a century. Let's learn the history of discoveries about the Milky Way, and what...
Ep. 98: Quasars
Last week we talked about galaxies in general, and hinted at the most violent and energetic ones out there: active galaxies. Quasars have been a mystery for half a century; what kind of object could throw out more radiation than an entire galaxy? A black hole, it...
Ep. 97: Galaxies
This week we're going to look at some of the biggest objects in the Universe: galaxies. It was the discovery of galaxies in the early 20th century that helped astronomers realize just how big the Universe is, and how far away everything is. Let's learn how galaxies...
Ep. 96: Humans to Mars, Part 3 – Terraforming Mars
And now we reach the third part of our trilogy on the human exploration and colonization of Mars. Humans will inevitably tire of living underground, and will want to stretch their legs, and fill their lungs with fresh air. One day, we'll contemplate the possibility of...
Student Questions: Collinsville High School
This is our third installment in our series of student questions shows and these questions come to us from Collinsville High School. Thanks to GLAST, Astronomy Cast is now able to provide equipment to send to high school teachers who want to Pamela and Fraser to do a...
Ep. 95: Humans to Mars, Part 2 – Colonists
After astronauts make the first tentative steps onto the surface of Mars, a big goal will be colonization of the Red Planet. The first trailblazers who try to live on Mars will have their work cut out for them, being in an environment totally hostile to life. What...
Ep 94: Humans to Mars, Part 1 – Scientists
We're learned about the failed missions to Mars in the past, and the current spacecraft, rovers and landers currently exploring the Red Planet. But the real prize will come when the first human sets foot on Mars. Robots are cheaper, but nothing beats having a real...
Ep. 93: Missions to Mars, Part 2
I know last week was a bit of a dry history lesson, but we wanted to give you some understanding of past efforts to explore Mars. Now we'll look at the missions currently in orbit, and crawling around the surface of Mars, and help you understand the science that's...