Linda and Tom Spilker with an update from Saturn this week on planetary radio. Hi everyone, welcome to Public Radio's travel show that takes you to the final frontier.

I'm Matt Kaplan. It's time for another Cassini update from

deputy mission scientist Linda Spilker but this time with a twist. Linda is

joined by her husband Tom Spilker also of JPL in the first of two conversations.

We are packed tighter than spam in a can this week with a brand new Q&A from Emily

Lachto-Wala and a what-up segment with Bruce Betts that goes to unheard of lengths to give

away a planetary radio t-shirt and I mean that literally. Let's get started with

Bill Nye the Science and Planetary Guy,

as Bill marks one of the biggest anniversaries and discoveries in space exploration history.

Hey, Bill Nye, the Planetary Guy here.

I'd like to talk to you about the 50th anniversary of Explorer 1.

Explorer 1 was a spacecraft launched by the United States

in response to Sputnik.

In the meantime, we tried to launch Vanguard, but it blew up. So Explorer

One was the first successful orbiting U.S. spacecraft January 31st, 1958. And this you could say is a piece of trivia, a footnote, no, no my friends.

Explore one discovered what are now called the Van Allen belts. Now the Van Allen belts, these are belts. These are

regions. Above the earth where fantastically energetic particles streaming from the Sun are trapped, are held in space

by nothing but the invisible Earth's magnetic field.

Quite remarkable. No one had had much thought about this. No

one had much thought about what happens to particles that might come off of a star

headed our way. They're held above, kept away from the Earth's surface by magnetism. And without

magnetism we would be totally different. What would we be? We would be

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