Starship Asterisk*

Am I the only one to notice that the caption to the dec 14 APOD mentions the tallest mountains yet observed- the near vertical ridge in picture- but that they failed to notice the huge massiff at the top of the picture? If the wee ridgelets are 1.5 Km high, how huge is the thing at the top of the photo?

http://antwrp.gsfc.nasa.gov/apod/ap061214.html
I didn't see it mentioned in the caption, Is there any idea what the "Black" area at the top of the image is??? I also noticed that the mountain ridges seem to be perfectly straight. Could this be from the radar imaging process?

The black shadow - clouds of ice particles? They reflect radar.

And a straight line - are we into crater chains again? A linear strike, that opens a crack down to liquid, that then wells up, into a linear mountain chain? Like the Mid-ocean rift on Earth, but with less gravity and no tectonics?

John

Later:
BINGO!
Cassini-Huygens website: http://www.esa.int/SPECIALS/Cassini-Huy ... IVE_0.html

"The mountains probably formed when material welled up from below to fill the gaps opened when tectonic plates pull apart, similar to the way mid-ocean ridges are formed on Earth. "

Maybe just tectonics, maybe craterchain?

I gloat!

John

The image is actually in the infrared range, not radar, but the same possibility of a shadow seems likely.