So a rock is a rock is a rock. Right? Across the solar system there are giant rocky asteroids and even "gianter" rocky moons. What is the difference between these two families of objects and where do they come from?

For the longest time the only gas giant planets that 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?

Good News! Over the next few years we're gonna 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, even Pluto? It turns out those places are far away. Today let's talk about the challenges of exploring the outer, outer solar system.

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.

So we're learning more & more about the outer planets of the solar system. Uranus & Neptune are Ice Giants, filled with water and other volatiles that we'd consider ice if it was here on Earth. What's inside these worlds and what can we expect to find across the Milky Way as we find more?

Funding for basic science has always been tricky business, coming mainly from universities, government, companies or wealthy individuals. But who knows how many fascinating discoveries were never made because of a lack of funding. And we now live in an era where regular people can come together to fund scientific discoveries.

Well, you're familiar with the Hubble Space Telescope of course, but it's just one of NASA's Great Observatories. After Hubble came 3 more incredible telescopes. Each greater than the last! (That's not true… The first one was the greatest.) But together they would fill in almost the entire electromagnetic spectrum.

After Pluto lost its planethood we were down to 8 planets. But there's growing evidence of another world or worlds out beyond the orbit of Pluto. Is Planet 9 out there and how will we find it? Could there even be a Planet 10?

So 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!

It's been 15 years since Pluto was kicked out of the planet club. It also happens to be the topic of our very first episode of Astronomy Cast more than 600 episodes ago. Are there any updates? Does Pluto have a chance of regaining planethood again?