Starship Asterisk*

These aren't impact craters, they are sinkholes.

Just out of curiosity, how do you know they're just sink holes?

Also, per this statement: "while the crater's center is visible on the lower right," where in the lower right is the crater visible? I thought it was the crater towards the upper center? (I guess that's what thought did for me! ) Hmmm, any clarification?

I believe it's the lower right of the crater rather than the lower right of the picture.
Orin

"where in the lower right is the crater visible?"

I think that's referring to the peak at the lower-right of the photo.

Looks to my amateur eye like it could be a complex crater: http://www.solarviews.com/eng/tercrate.htm

If Dione's made of ice -- or at least, has an icy covering -- then perhaps whatever it was that slammed into the surface had not only sufficient kinetic energy in it to leave a crater but also heat energy which then melted the surrounding ice as it went into the surface, leaving those fresh white walls that give the impression of a sinkhole ...

Ch.

Can Cassini get closer or there is an atmosphere on the beast ?? Is Cassini able to change orbit ???

There is no atmosphere on Dione, Cassini may get closer on a future pass, it requires too much fuel to make anything other than small corrections or changes in it's orbit.

In the picture of Dione posted 26 October 2005, there appear to be many fine lines running about 355 degrees from bottom to top. Are they caused by the photographic process or are they actual lines on the surface? If surface lines, is there a hypothesis as to their cause (origin)?

With out sounding to "un-political", I give those lines running between 11:30 and 5:30 about a 90 percent chance of being what are known as catina, catine, catini, or commonly known as crater chains.

Norval

And again Dione is the main point of discussion from this image.
http://antwrp.gsfc.nasa.gov/apod/ap051026.html

FieryIce (Gale) and I may have to admit that Dione has more crater chains than any other surface, even beating out Mars and Phobos.

Norval

S. Bilderback wrote:There is no atmosphere on Dione, Cassini may get closer on a future pass, it requires too much fuel to make anything other than small corrections or changes in it's orbit.

What the heck is this about fuel? Cassini has over 74 lbs of Plutonium, three genies, I don't recall if that is over 74 lbs per genie or just over 74 lbs period, so what is this about fuel?

http://antwrp.gsfc.nasa.gov/apod/ap051026.html

If this is the image you are talking about, they look like cracked ice to me.

Ok, but, uhmmmmmm don't put any ice in my drink please.

Downloading the higher res pics shows the crater chains much better.

Norval

I was under the impression that "Crater Chains' have a definite starting point and a definite stopping point. these small lines traverse large areas and, to me at least, resemble stress fractures similar to europa.

hmmmm you may want to get a better high resolution monitor?

I run dual 19 inch View Sonic CRT .21 flat screen monitors for image viewing.


With out going in for a monitor that costs thousands of dollars I have found them to be the best.

Norval

Craterchains,
The original image on APOD is only 156K - how can your superduper monitor show any more detail on that than an ordinary one?

So please show us where the craters are, using one line as an example.

I enclose a reduced image with arrows that show one 'streak', taken at random, that I can follow from top to bottom without a break, but NOT as a straight line. Surely a crater chain must be straight, or at least curved as it rounds a planetoid, not wiggly like this and most of the others?


John
(A convert in some cases! But not in this.)

BMAONE23
According to the scientists that research these things crater chains can have quite a variable. My personal requirements are a bit different, a bit more exacting that eliminate many of their "accepted crater chains".

Well, JohnD, Jim Bignell can see the "lines", the JPL site speaks of them, I see them, others have seen them, and you see one broken one. And by the way, the image on APOD is only 60kb. The .jpg file at JPL is as big as you say, and the .tif is 1 + meg. file.
But all that aside. Show "us"? Who else wants to know?

I may have a personal opinion, or two, about these types of crater chains, but it isn't "politically correct". My crater chain research ended over a year ago, other than collecting any new images that come in and show CS types of crater chains. You may have to ask someone over at BA to "show" them to you. Or, they may have another opinion as to what all those parallel lines are?

Norval