Weird Stuff In Space

A few years ago I had a question about the Cassini space probe. I sent an email to Carolyn Porco of the imaging team, who I didn't know. She answered my query and put me on her mailing list.

This is a great mailing list - possibly the best I'm on!

Cassini has been orbiting Saturn for a while, moving in and out of the rings and past Saturn's multitude of moons. I'd put a number, but no one really knows how many there are, plus a lot depends on your definition of a moon!

One of the latest stops for Cassini was a nice photo session with Hyperion. It's reddish in color and pock marked with craters. Like so much else in space, Hyperion is potato shaped.

The potato factor has been constant topic of conversation between Dave brody, my former producer on Inside Space, and me. We have no idea why the natural order of space has chosen this particular vegetable to model so much on.

On most solid planets and moons, an incoming meteorite blasts into the surface, ejecting a significant portion of what was there. On hyperion, an oncoming meteorite hitting the surface would primarily compress it. Very little would be blasted back into space - even with Hyperion's minimal gravity.

All I could think of was Styrofoam. Hyperion acts as if it's made of Styrofoam!

Like Styrofoam, Hyperion is isn't very dense. If you had a large enough bathtub, Hyperion would float (as would Saturn itself). Hyperion has half the density of water.

I'm getting a little jealous. It seems we know more about Saturn and its moons than we know about Earth and ours. The Cassini instrumentation is quite good and has produced tons of data.

In fact, Casini was able to measure its effect on Hyperion as it looked on from 30,000+ miles away.

“The close flyby produced a tiny but measurable deflection of Cassini’s orbit. Therefore, the orbit determination, carried out by our Italian colleagues, allowed us to estimate the mass with fairly good accuracy,” said Cassini radio science deputy team leader Nicole Rappaport of the Jet Propulsion Laboratory in Pasadena, Calif. “Combined with the determination of Hyperion’s volume from imaging data, this provided an accurate computation of its density.”

That's ridiculously precise!

Is there a practical application for the money spent on this mission? I can't see any and yet I'm pleased by the 'science in the abstract' we've been able to pull out. And, I thank Carolyn for sneaking me onto her list.



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This page contains a single entry by Geoff Fox published on 07/06/07 6:34 PM.

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