We're so familiar with the current configuration of the planets in the Solar System, but did the planets always orbit in this way? Did they form further out and then migrate inward to their current positions? And what about other star systems out there?

AstronomyCast 293: Earthquakes, by Fraser Cain & Dr. Pamela Gay

We created Astronomy Cast to be timeless, a listening experience that's as educational in the future as it was when we started recording. But obviously, things have changed in almost 7 years and 300 episodes. Today we'll give you an update on some of the big topics in space and astronomy. What did we know back then, and what additional stuff do we know now?

AstronomyCast 292: The Oort Cloud, by Fraser Cain & Dr. Pamela Gay

Sometimes a trilogy needs four parts. We've looked at the history and modern era of space stations but now it's time to peer into the future at some space station concepts still in the works. Most of these will never fly, but the ideas are important. We can't call ourselves a true spacefaring civilization until humans live permanently outside the Earth.

AstronomyCast 291: Shockwaves, by Fraser Cain & Dr. Pamela Gay

AstronomyCast 290: Failed Stars, by Fraser Cain & Dr. Pamela Gay

And now we reach the third part in our trilogy on space stations, with the largest vehicle ever assembled in space: the International Space Station. Launched in 1998, it now consists of 450 metric tonnes of modules, power systems and spacecraft and is regular host to a handful of astronauts from many countries.

AstronomyCast 289: Cherenkov Radiation, by Fraser Cain & Dr. Pamela Gay

Last week we introduced the history of space stations and focused on the US and Soviet stations that were launched. This week we look at one of the longest running missions ever launched: Mir. From its launch and construction to its fiery finale, Mir helped both the Russians and the Americans extend their understanding of what it actually takes to live in space.