Did you catch the wave at Saturn? We will this week on planetary radio.

Welcome to the Travel Show that takes you to the Final Frontier.

I'm Matt Kaplan of the Planetary Society back from vacation along with our whole gang.

You'll hear from Emily and Bill in a few moments.

Then we'll go to the Jet Propulsion Lab, home of the Cassini Mission,

where hundreds of people came out in the hot summer sun to be part of a virtual

selfie snapped by the 900 million mile distant spacecraft.

We'll also hear from the leader of a group that waved at the ring planet from the English countryside.

I forgot to ask senior editor and planetary evangelist Emily Lachowala if she saluted Saturn.

ELLi, what is planetary geomorphology?

Well, it's a study of the shapes of the landscape and what they tell you about the history of a place.

Geomorphology is, of course, extensively studied on Earth, but thanks to planetary missions we can study it on other planets as well.

The piece was written originally by a geomorphologist named Joe Levy for other geomorphologists and so there's quite a bit of vocabulary in there that you may have heard before. For instance, I'm sure you're familiar with the term permafrost.

But when you say permafrost to a geomorphologist, there's a huge amount of context that comes in about what that means

about the environment.

And so I had to supply a little bit of that context that would ordinarily be at the tip of the

tongue of any other self-respect and geomorphologist,

just to help people understand why it's important

that permafrost is actually not quite as perma

as its name implies.

It melts a little bit every year on Earth,

and apparently it also does on Mars. and Levy was making the argument in this

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