As the ice-encrusted moon Enceladus makes it way along its orbit around Saturn it gets repeatedly squeezed by the giant planet’s gravity, like a frozen stress ball with water-filled insides. This constant squeezing and relaxing generates friction heat in the moon’s crust, which could be responsible for keeping some of its internal water liquid and spraying it out into space from long canyons that cut across its southern pole. And sometimes more ice gets shot out than at other times, forming a trail of long tendrils that stretch into the “E” ring – a hazy, diffuse doughnut around Saturn made from Enceladus’ icy exhaust.
These tendrils had been observed by the Cassini spacecraft since 2006, but only now have they been positively confirmed to be the results of specific geysers on the 318-mile-wide moon.
We’re all used to seeing fantastic images of Saturn and its family of moons from NASA’s Cassini spacecraft, which has spent the last decade in orbit around the ringed world. But every now and then Cassini aims its cameras outwards, capturing images of the sky beyond Saturn – just like we might look up at the stars from here on Earth. And while it’s not designed to be a deep-space observatory like Hubble or Subaru (or even like a modest backyard telescope, really) Cassini can still resolve many of the same stars we can easily see in the night sky… and, on April 12, 2015, it spotted something much farther away: the Sombrero Galaxy (M104), 29 million light-years distant!
Coincidentally Cassini grabbed its image of M104 exactly five years after it was imaged with Japan’s Subaru Telescope, located atop Mauna Kea.
Here’s a raw image of Saturn’s moon Iapetus, looking down on its northern hemisphere from Cassini on March 31, 2015. The moon’s signature two-toned coloration is evident as its bright icy surface is partially coated by dark material, thought to have been ejected from distant neighbor Phoebe.
Iapetus is 914 miles (1,471 km) in diameter, or about as wide as Texas and Louisiana combined. It orbits Saturn at a considerable distance of 2,212,889 miles (3,561,300 km), which is nine times farther than the Moon is from us.
Iapetus’ north pole is located just below and to the left of the centrally-peaked crater south of the brightest region in the image above. (The two prominent craters near image center are Roland and Turpin.)
After spending a couple of years in an orbit riding high over the northern pole of Saturn Cassini has swung back down alongside the planet’s ringplane, in perfect alignment to once again capture views of the icy moons that reside there. The image above is a composite made from several narrow-angle camera images acquired by Cassini on Feb. 9, 2015, showing an extended color view of Rhea as the spacecraft was heading to perform a targeted flyby of the larger haze-covered moon Titan.
Saturn’s second-largest moon, the heavily-cratered Rhea wouldn’t appear this golden to our eyes; its natural colors are much more monochromatic (i.e., grey.) But Cassini can “see” in light stretching from ultraviolet to infrared, and that added range lets us see Rhea in a new light.
If you’re in love with space exploration then you’ll fall for this: it’s the picture of Earth taken from the Voyager 1 spacecraft after it passed the orbit of Pluto in 1990. That image of our planet from almost 4 billion miles away inspired Carl Sagan to write his famous “Pale Blue Dot” passage, and reminds us that we are all just floating on “a mote of dust suspended in a sunbeam.”
This is from a post I originally published in 2010. I’ll keep trotting it out until it’s not cool anymore. (Which I don’t think will ever happen.)
On February 14, 1990, after nearly 13 years of traveling the solar system, the Voyager 1 spacecraft passed the orbit of Pluto and turned its camera around to take a series of photos of the planets. The image above shows those photos, isolated from the original series and are left to right, top to bottom: Venus, Earth, Jupiter, Saturn, Uranus, and Neptune.
From that distance, over 4 billion miles from the Sun, the planets each appear as little more than a bright dot against the vastness of interplanetary space.
“That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. … There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world.”
– Carl Sagan
It may not be in color but that doesn’t make it any less beautiful: this stunning image from Cassini shows Saturn and its largest moon Titan – the second-largest moon in our solar system, after Jupiter’s Ganymede – from their night sides, both showing their crescents against the blackness of space.
Titan’s crescent nearly wraps all the way around its globe, because of the way its thick atmosphere scatters sunlight.
The view was obtained at a distance of approximately 1.1 million miles (1.7 million kilometers) from about 3 degrees above the ringplane. The image was taken in violet wavelengths with Cassini’s wide-angle camera (WAC) on Aug. 11, 2013.