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.

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?

Want to travel the world but you don't have a lot of money? No problem, your continent is drifting across the surface of the Earth right now. In a few million years, you'll reach your destination.

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.

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?

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?

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!

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.

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?

This week the shows include: Dec 08: A New Look at the Drake Equation by David Black; Dec 09: Mercury’s Volcanoes by Bob Hirshon, AAAS; Dec 10: Aryabhatta by Brains Matter; Dec 11: Europa's Oceans and Possible Life by AstronomyCast; Dec 12: 'Twas the Observer's Day Before Christmas by Pamela Gay; Dec 13: Encore: Exploring Space with Your Computer by Bruce Irving; Dec 14: Aliens in Fact and Fiction by Walden School.