Not much to say about this one but, wow. This is better than the famous hi-res Saturn image from early in the Cassini mission. The composite image was made by Ian Regan who is a freelance imager.
Rhea is the second largest of Saturn’s moons but lacks any of the exciting features of some of the others. It has some of the “wispy” features that have been determined to be ice cliffs on Dione, but they are far less prominent here. Just another big ball of water ice for future earth visitors to mine for resources!
One of the mid-sized moons of Saturn, Tethys, is thought to be composed almost entirely of water ice. Its most remarkable features are Odysseus, a 400 km wide crater and the Ithaca Chasma a 2,000 km long valley that runs across 2/3 of Tethy‘s globe. Those features are not visible in this image, but what is visible is the slight color variation which almost appears as a “dusting” of color on a largely grey body. A curious feature especially considering the radical color variation found at Iapetus. Perhaps this discoloring is a more subtle result of the same event which caused the strange color variation on Iapetus?
This is a great way to truly understand the capabilities of the Mars Reconnaissance Orbiter. This image of Jupiter is taken from Martian orbit which is 357 million miles away. It is comparable to the what the New Horizons is seeing as it actually approaches Jupiter, which is currently 38 million miles away. So if you were wondering how MRO can get those incredibly detailed images of rovers and landers on the surface from orbit… now you can scratch your head and wonder how it can see Jupiter as good as a probe that is actually approaching a flyby in a few weeks.
Okay, so not as exciting a wallpaper as most… but it was taken from Mars and you can see (i’m guessing) is Europa, Ganymede and Callisto in the same shot.
Just not enough Jupiter images on here yet. The Moons are Europa (further from) and Callisto (closer to).
A few decades ago, about 12 men walked upon the surface of another celestial body for the first time in history. At one point, Neil Armstrong looked up at Earth and blotted it out with his thumb and thought the significance of that simple act. “That’s home. That’s us. On it, everyone you ever heard of, every human being who ever lived, lived out their lives. The aggregate of all our joys and sufferings, thousands of confident religions, ideologies and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilizations, every king and peasant, every young couple in love, every hopeful child, every mother and father, every inventor and explorer, every teacher of morals, every corrupt politician, every superstar, every supreme leader, every saint and sinner in the history of our species, lived there on a mote of dust, suspended in a sunbeam”. While these were not Armstrong’s words, but instead Carl Sagan’s, it is clear that it is along these similar lines he was thinking.
It is easy to forget how incredible those moments were as they happened so long ago, and the first of these was some months before I even existed as a person. We have grown accustomed to these images of men walking on the moon, in no small part because a follow up is so long overdue that they seem antiquated or quaint. So it seemed to me that out of 50 wallpapers uploaded it might be appropriate to include man’s first exploration of any of these places as part of the collection.
As of this time, Triton (a moon of Neptune) has the coldest temperature ever recorded in human history on any terrestrial surface… -235 C, -391 F. At these temperatures, nobody would have expected anything other than a huge frozen solid ice ball. Instead, Triton is littered with what we now call cryo-volcanos… or cold volcanos. They erupt or eject materials other than molten rock, such as water, ammonia or methane. As we are seeing in places like Titan (who is also suspected of having cryo-volcanos) many characteristics of Earth geology and weather are simulated elsewhere in the Solar System with different materials. On Earth it rains water, but on Titan it rains methane, and likewise on Triton it erupts probably liquid nitrogen instead of magma as it does here on Earth.
Only two active cryo-volcanos have been confirmed on Triton, but it is generally assumed that each one of those black smudges visible in this image are the remnants of recently active cryo-volcanos. There are quite a few…
Saturn’s moon Dione seen at almost full disk. Recently the “wispy” markings have been revealed to be giant ice cliffs as seen by the Cassini spacecraft after coming close to 500km from the surface. The cliffs reach as high as several hundred meters high and are thought to be the result of ancient tectonic fractures.
A composite image of some very active lava flows on Jupiter’s moon Io.
One of the expectations of ramming a space probe into a comet was to be able to see the resulting crater. The Deep Impact collider was released and the Deep Impact probe continued on from a distance to record the impact. What it saw was a blast much larger than expected and was so large that direct visual observance of the resulting crater became impossible. However, the same thing which kept us from seeing some of these results is the same plume of ejected material that has told us that more about this comet’s composition and how the surface materials are held together quite weakly.
Gordan Ugarkovic has a great collection of reworked Cassini images on Flickr. I contacted Gordan about showing some of his images here on wanderingspace and he was ever so gracious. As many people Gordan is “somewhat underwhelmed by the frequency the Cassini Imaging Team releases color composites”, so it is up to excellent freelancers like him to compile this information from the data files which are made public by NASA. Problem is that these images rarely make it to the mass media and we are stuck with the dozen or so color images the NASA imaging teams decide to produce in a year.
WALLPAPER NOTE: The left 1/3 of the “Three Moons” image was extended in Photoshop using data at the edges of the original image which was cropped to a square format. This “fake” imagery was only applied to that area of the rings and the rest of the image including the moons is actual.
Here are some other images from Gordan which are some of my favorites, but don’t trust my editing… go to the gallery and have a look yourself. For the sake of posterity I have added a permanent link to his gallery on the right side of this blog where you may note that there are already a few others linked. There were two additional ones but the sites have been taken down since I linked to them?! Hopefully the three left will stick around for a while and I will in time add more to the collection.
Tethys and Saturn’s Hazy Limb
Mimas and Prometheus on Rings
Io on Jupiters Edge
Currently the Cassini spacecraft is orbiting Saturn during Saturnian Winter unlike when Voyager sped by in the 80’s when it saw an almost globally peach colored Saturn. During this winter, the rings tend to keep the region in shadows and the theory goes that this lowers the temperatures and break up the peach colored clouds and “clear” the skies to reveal this blue. If this is the case, we are seeing deeper into the atmosphere here than we do in the areas blanketed by the more peach colored top clouds.
The image shows the northern pole of Saturn and those bands are the shadows of the rings on the cloud tops. You can see some smaller cloud formations in between the shadow gaps which gives a very alien Saturn some Earth-like familiarity.
Trying to think of the best image to post for Christmas, I figured this snowy looking crater on Mars would do. Not nearly as exciting as the recently discovered flowing water on Mars, but for an alien winter scene… it’ll do.
We have all seen plenty of craters in the Solar System but none appear the way they do on Hyperion. As of this time there are only loose theories about the nature and cause of Hyperion’s sponge-like appearance. Brighter outer layers give way to darkened crater bottoms and do this fairly consistently across the entire surface of Hyperion. It is also is second largest irregularly shaped body in the Solar System (#1 being Neptune’s Proteus) and is one of the only chaoticly rotating bodies ever discovered. The spin-axis is so insane that any future visitors to Hyperion will have to wait until they are real near-by to decide where they might be landing as it is actually near impossible to project how Hyperion will be oriented at any given future moment.
IMAGE NOTE: The color was overlaid from another image of Hyperion and the is largely artistic.
One of my favorite wallpaper images from the Cassini mission. This image almost looks like one of the fantastic Chesley Bonestell images from the 80’s only its not a painting. What you see are Saturn’s rings along the bottom and tiny Mimas floating across Saturnian cloudtops which are being shadowed by the rings. It is thought that these deep shadows, in addition to Saturn currently being in winter, somehow cause less clouds to form in Saturn’s northern hemisphere and create the blueish appearance seen here. When the Voyager’s passed by Saturn in the 80’s the entire globe appeared to be peach colored and lacked any of the blues you see today.
IMAGE NOTE: The left 1/5 of the image (the rings) is a digital extension of the image data found near the edge of the original image. This was done simply to fill out the proportion as the original was cropped to about 4/5 the the width.