Shadows on the Rings

...EccoVi un altro esempio delle "gigantesche navi spaziali" che si muoverebbero attraverso gli Anelli di Saturno, secondo il Dr Bergrun...

In realtà è soltanto la lunga ombra della luna saturniana Tethys la quale, all'avvicinarsi dell'Equinozio, si stende sugli Anelli del Gigante Gassoso, dando l'impressione - ma solo ad un osservatore completamente disattento - della esistenza di un vascello scuro a forma di fuso che si muove attraverso gli Anelli "F" ed "A".

Caption NASA:"Joining other moons in heralding the coming of Saturn's August 2009 Equinox, the moon Tethys casts its shadow across Saturn's F-Ring and part of the A-Ring.
The penumbra, or outer non-opaque part of Tethys' shadow, has intersected the A-ring. Only around the time of Equinox are the shadows of the moons cast onto Saturn's Rings. For an animation of the moon Epimetheus casting a shadow on the A-Ring, see also PIA11651.

The image on the left was taken in Visible Light with the Cassini Spacecraft wide-angle camera on March 20, 2009. The image on the right was taken with the narrow-angle camera at nearly the same time. Tethys itself is not visible in these images, but the small moon Prometheus can be seen between the F and A-Rings in the top of the wide-angle camera image.
This view looks toward the unilluminated side of the Rings from about 37° above the Ring-Plane. The view was obtained from a distance of approx. 880.000 Km (about 547.000 miles) from Saturn and at a Sun-Saturn-Spacecraft, or Phase, Angle of 124°.
Image scale is roughly 49 Km (about 31 miles) per pixel in the wide-angle image. In the narrow-angle camera image, the scale is roughly 5 Km (a little more than 3 miles) per pixel".