Shaping Dione


Dione_TectonicsThis image of Saturn’s moon Dione shows a mixture of features: bright, linear features showing evidence of tectonic movant and impact craters. The tectonic features reveal that Dione has been heated and cooled since its formation, and scientists use those as clues to piece together the moon’s past. The impact craters are evidence of external debris striking the surface and tell about the environment in which the moon has existed over its history.

Image Credit: NASA

Shadow on the Rings


ring shadows 2The changing length of Saturn’s shadow marks the passing of the planet’s seasons. As the planet nears its northern-hemisphere solstice in May, 2017, the shadow will get even shorter. At solstice, the shadow’s edge will be about 45,000 km from the planet’s surface, barely making it past the middle of the B ring.

The white speck in the lower left of the picture isn’t a dust mote on your monitor. It’s the moon Mimas, only a few pixels wide in this image.

Image Credit: NASA

Broken Rings?


broken ringsThat’s not a gap in Saturn’s rings. It’s the planet’s shadow. During most of Saturn’s year, the planet’s shadow extends well beyond the edge of the rings.  However, with summer solstice fast approaching, the Sun is higher in Saturn’s sky and most of Saturn’s A ring is completely shadow-free.

Saturn’s large moon Titan, its northern hemisphere in sunlight of late spring, hangs above the rings.

Image Credit: NASA