There are asteroids and there are comets. But there’s an entirely separate class of objects called centaurs. But instead of half-human, half-horse, imagine an object that’s half comet, half asteroid but 100% interesting.
Our Hosts
Fraser Cain
Universe Today
Dr. Pamela Gay
CosmoQuest
Production by
- Richard Drumm, Audio Engineer
- Ally Pelphrey, Video Engineer
18 Seasons
700+ Episodes
2018 Winner Parsec Award
Ep. 613: Pluto’s Demotion: 15 Years Later
Astronomy Cast more than 600 episodes ago. Are there any updates? Does Pluto have a chance of regaining planethood again?
Ep. 612: Update: SETI, METI (and WETI)
Last week we talked about the various ways that astronomers could detect the presence of intelligent civilizations by observing technosignatures. This week we’ll give you an update on the state of searching for extraterrestrials. This field has gone from a collection of pariahs to a completely legitimate field of research. What’s changed?
Ep. 611: What is Required to Confirm Alien Life: Intelligence Edition
Last week we talked about what it’s going to take to confirm basic biological life across the Solar System and the Milky Way. This week, we’ll discuss what it’s going to take to detect intelligent life out there in space.
Recent Episodes
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...
Ep. 92: Missions to Mars, Part 1
With last month's safe arrival of the Phoenix Mars Lander, Mars enthusiasts breathed a collective sigh of relief... phew. Now it's time to search for evidence of organic molecules in the ice at Mars' north pole. But this is just the latest in a long series of missions...
Ep. 91: The Search for Water on Mars
With the successful touchdown of the Phoenix Lander, NASA is continuing its quest to find evidence of past and present water on Mars. This week we discuss the geologic history of Mars, and explain why NASA thinks the story of water on Mars is so important. And how...
Ep. 90: The Scientific Method
You've heard me say it 90 times: "How we know what we know." But how do we know how we know what we know? So astronomers like all scientists use the scientific method. Without the scientific method we'd probably still think the Earth is flat, only a few thousand years...
Ep. 89: Adaptive Optics
Since the dawn of humanity, astronomers have wished to destroy the atmosphere. Oh sure, it's what we breathe and all, but that stupid atmosphere is always getting in the way. Since destroying the atmosphere is out of the question, astronomers have figured out how to...
Ep. 88: The Hubble Space Telescope
Our understanding of the cosmos has been revolutionized by the Hubble Space Telescope. The breathtaking familiar photos, like the Pillars of Creation, pale in comparison to the astounding amount of science data returned to Earth. Hubble's getting old, though, serviced...
Ep. 87: The End of the Universe Part 2: The End of Everything
Hopefully you've all recovered from part 1 of this set, where we make you sad about the future of the humanity, the Earth, the Sun and the Solar System. But hang on, we're really going to bring you down. Today we'll look far far forward into the distant future of the...
Ep. 86: The End of the Universe Part 1: The End of the Solar System
This is a show we wanted to do since we started Astronomy Cast but we always thought it was too early. We wanted you to know that we're positive, happy people with enthusiasm for astronomy and the future. It's time for some sadness. It's time for a grim look to see...
Ep. 85: Detectors
Our senses can only detect a fraction of the phenomena happening in the Universe. That's why scientists and engineers develop detectors, to let us see radiation and particles that we could never detect with our eyes and ears. This week we'll go through them all, so...