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Fraser
2006-Mar-09, 04:45 AM
SUMMARY: This view of Iapetus, one of Saturn's moons, shows its terminator running from pole to pole. This is the line that separates night from day on the moon, and right along this line, the shadows are very long. This allows planetary geologists to see a tremendous amount of detail and measure the height of mountains and the depths of craters. Cassini took this photograph on January 22, 2006, when it was 1.3 million kilometers (800,000 miles) from Iapetus.

View full article (http://www.universetoday.com/am/publish/jpl_iaptus_terminator.html)
What do you think about this story? post your comments below.

antoniseb
2006-Mar-09, 01:09 PM
Iapetus is very interesting to me. There is no way that Cassini will be able to tell me as much about this object as I want to know.

jkmccrann
2006-Mar-10, 09:59 AM
I think the entire Saturnian system is extremely interesting. I would love to see another probe in that part of the Solar System as soon as possible - preferably with some sort of possible lander for the `surface' of Titan.

If we could identify solid ground on Titan to land on - I'd hope there would be a strong consensus to try and include that in any future mission to the system, I fear though that I may have a bit of a wait on my hands in that regard. Could well be the 2030s before something like that happens.

antoniseb
2006-Mar-10, 12:38 PM
Could well be the 2030s before something like that happens.

Or later. Landers and radar probes to the Saturn moons would be very interesting, but I suspect it won't be in the budget for many years to come. The new technology spacecraft have to become cheap and reliable before we'll be doing that.

nizmo_man
2006-Mar-13, 01:38 PM
People still think that Iapetus is some kind of supermassive manmade satellite?
Sometimes we do wish it were true, that some advanced civilisation left it behind for us to discover when the time's right or something.
Anyways I'm just babbling on now

doma
2006-Mar-14, 08:22 AM
Does Cassini have other methods to determine the heights of the mountains and depths of crators? Or do the scientists have to resort to indirect measurements such as using the shaddows for lack of a particular type of instrument? Or does the use of shaddows add to / complement the elevation data gathered in a more direct manner?

I first hear of Iapetus only a few years ago while reading 2001 for the first time. The sci fi author made it very mysterious; with great speculation on why it has a light and dark side. Then, by coincidence, we arrive and take high res pictures and we can see for ourselves what it's really like. amazing!

thanks-
-doma

ps> first post ;)

doma
2006-Mar-14, 08:29 AM
Well ... I went to the JPL site and sure enough there's a page on the spacecraft and its instruments. Seems it does have a radar for use in "measuring the height of surface objects such as mountains and canyons."
(http://saturn.jpl.nasa.gov/spacecraft/instruments-cassini-radar.cfm)

So then, the use of shaddows is either an interesting excercise but redundant ... or a way to verify the radar ... or complements the radar data in some way ... or they can't/haven't used the radar on Iapetus yet.

Anybody know which?

-doma