Backstage Pass to Iapetus

October 18, 2007
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1671. Giovanni Cassini, the astronomer, discovers a moon near Saturn. Half is dark as coal. The other half, bright as snow. Three centuries later, Cassini, the spacecraft, flies by for a close look.

Bob Mitchell, Cassini Program Manager:

We flew by Iapetus yesterday morning. The data coming down right now, I haven't seen. More importantly, the scientists sitting down here who are going to comment on it for you, have not seen it either (laughter).


Scientists have waited hundreds of years to see Iapetus close up.

Bonnie Buratti, Cassini Scientist:

What does it mean that we will bring an object a hundred times closer? There are two people standing there. You have to trust me. If you bring these people to three feet, which is a factor of a hundred better in resolution, this is what you see. (Laughter) That is how much closer we are going to get to Iapetus.

Shadan Ardalan, Jpl Engineer:

We don't get opportunities like this to see science come down in real time and see the fruits of our work, you know, this quickly.

Nagin Cox, Jpl Engineer:

I thought one of the most human moments was when we're all looking at this one image going --Hm? Hm? You know, what are we all looking at???

And then it was flipped over.

Voice Off-Camera:

Can you rotate that one?

Nagin Cox:

And everybody went - Ahhhhhhhhh. laughter)

Voice Off-Camera:

Thank you.

Nagin Cox:

And it reminds you that when you're seeing something for the first time, you don't have a context. You don't even know which way is up.

Torrence Johnson, Cassini Scientist:

This ridge is very different from the types of things we see on Europa, for instance, where you have fractures.

Amanda Hendrix:

Look at this one. That one looks like another landslide crater.


Since then, Cassini scientists have had time to study the images and crunch the numbers.

Amanda Hendrix:

We spent a lot of time over the light-dark boundary. It's never been seen at very high resolution before. Any bright stuff such as water that might have been mixed in with the dark stuff originally is going to evaporate out because the dark stuff is going to be warmer. And the ridge is something so unique to Iapetus and so interesting. It's very heavily cratered, which tells us that it's very old. Basically, we don't have all our questions answered yet. There's a lot to still be learned about Iapetus.


There's really nothing quite like discovery.

Natural Sound:

"Hello this is Arthur Clarke"


The gathering heard from one of Cassini's biggest fans, Arthur C. Clarke, who featured Iapetus is his book "2001: A Space Odyssey."

Arthur C. Clarke:

Thanks to the World Wide Web I've been following the progress of Cassin-Huygens. I've seen enough instances where nature imitates art., so I'm going to keep my fingers crossed for what Cassini discovers at Iapetus.


With fingers crossed and eyes wide open, sci-fi fans and scientists savor the joys of Iapetus.