Neil degrass Tyson on Planetary Radio. Radio. Welcome to the Travel Show that takes you to the Final Frontier.

I'm at Kaplan of the Planetary Society.

This time that Final Frontier is Cosmos, a space-time odyssey, the awe-inspiring television

series hosted by Dr. Tyson.

We get a behind-the-scenes scenes look and we'll talk to Neil about

where he'll go after he completes this tour of life, the universe, and everything.

Bill Nye and Bruce Bats are also here. Got a great prize for the winner of the new space

trivia contest and you can't go wrong if you begin with senior editor

Emily Lochuwala. Emily I'm looking back to an April 30 blog entry that you did. Let me start with this question.

Who is the Kuiper belt Big Shot, Pluto, or Aris?

We don't actually know yet and I kind of hope that this answer gets solved or this question gets solved by discovering something that's bigger than both of them out there.

But in the meantime we have a tie for the largest thing in the Kuiper belt. We don't know whether Pluto or Eris is bigger.

We do know that Eris is more massive, but when school kids ask, you know, which thing is the biggest

in the solar system or rank things in order they don't care about how many

kilograms something is they care about diameter and within the error that we can

measure the map we do not know which is bigger Pluto or Eris why is this such a

complicated thing to figure out and you even talk to Alan Stern

of the New Horizons mission about this.

Yes, well, it's complicated for a number of reasons.

One of the reasons is that these things are very far away,

so you can't directly image them

to measure their size they're generally not

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