Peak Time

Cassini soars over a peaked crater on Dione

A crater’s central peak casts a long shadow in this image from Cassini, taken on October 17 as the spacecraft passed by Dione at a distance of 25,000 miles.

700-mile-wide Dione is literally covered in craters, faults and gouges, a testament to the ancient age of its frozen terrain. Many larger craters – like the one seen here – have central mountains that rise higher than the crater rims, catching the sunlight on their icy peaks. Unlike mountains on Earth that were formed by the crumpling of tectonic plates or by volcanic activity, crater peaks were formed by the initial impact that formed the crater itself, when the molten surface rose up at the center of the impact site and cooled rapidly, maintaining a pointed shape.

This site is located on Dione’s “leading” side – the side that faces forward as it orbits around Saturn. You can see another image of this location here, captured by Cassini in December 2005. The crater just below center on the left side of that image is the same one seen above…Cassini would be coming toward it from just about its ten o’clock position to get this view.

I adjusted the raw image levels and sharpened it to enhance surface detail, as well as de-interlaced the right side to remove horizontal lining. (See the original image here.)

Credit: NASA / JPL / SSI. Edited by J. Major.