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Spot the specks of Saturn's moons

NASA / JPL-Caltech / SSI

Two of Saturn's more than 60 moons join the ringed planet in this scene, captured by the Cassini orbiter on Jan. 19 and released on April 30. Tethys appears as a small white dot above the rings on the far left of the image. Enceladus appears as a smaller bright speck beside the planet. The rings cast wide shadows on the planet's southern latitudes.




Two of Saturn's moons are dwarfed by the giant planet and its rings in this family portrait from the Cassini spacecraft, which will mark its eighth year in Saturnian orbit in July. This image was put out by the Cassini imaging team on Monday, just a little too late to make our Top 20 roundup for the Month in Space Pictures — but it's worth passing along as a bonus prize.

You can see 660-mile-wide Tethys as a white dot toward the left edge of the image, and 313-mile-wide Enceladus as a smaller bright speck beside the planet. Tethys is thought to be composed mostly of water ice with a bit of rock mixed in, while Enceladus is a very special case: Cassini has repeatedly documented geysers of water ice spewing from fissures in that moon's surface — suggesting that liquid water and perhaps even living things may lie beneath. It'll be up to a future probe to plumb the mysteries of Enceladus more deeply.


Saturn's rings are seen nearly edge-on, and in this picture they're casting wide, curved shadows on Saturn's southern hemisphere. Bad Astronomy's Phil Plait says he can't help noticing the thin white ribbon of clouds stretching across the planet's northern hemisphere. Those may be the remnants of a monster storm that wrapped itself around the globe for months, starting in late 2010. "Our gas giants don't screw around," he writes. "When they do something, they do it big."

And when we do the Month in Space Pictures slideshow, we do it big as well. Click on the image below to see some of the best out-of-this-world views from the month of April. You'll find shots from the final flights of the shuttles Discovery and Enterprise, photos of weird phenomena on Mars and Uranus, and even a UFO (Galaxy, that is). If you want to find out more about the stories behind the pictures, leave a comment and I'll try to point you in the right direction.

NASA/SDO/AIA

Click through a solar eruption, the final odyssey of the shuttle Discovery and other outer-space highlights from April 2012.


Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter or adding Cosmic Log's Google+ page to your circle. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for other worlds.