Astronomy Picture of the Day Search Results for "enceladus"

APOD: 2009 January 11 - In the Shadow of Saturn
Explanation: In the shadow of Saturn, unexpected wonders appear. The robotic Cassini spacecraft now orbiting Saturn recently drifted in giant planet's shadow for about 12 hours and looked back toward the eclipsed Sun. Cassini saw a view unlike any other. First, the night side of Saturn is seen to be partly lit by light reflected from its own majestic ring system. Next, the rings themselves appear dark when silhouetted against Saturn, but quite bright when viewed away from Saturn, slightly scattering sunlight, in this exaggerated color image. Saturn's rings light up so much that new rings were discovered, although they are hard to see in the image. Seen in spectacular detail, however, is Saturn's E ring, the ring created by the newly discovered ice-fountains of the moon Enceladus and the outermost ring visible above. Far in the distance, at the left, just above the bright main rings, is the almost ignorable pale blue dot of Earth.

APOD: 2008 December 22 - Labtayt Sulci on Saturns Enceladus
Explanation: Do some surface features on Enceladus roll like a conveyor belt? A leading interpretation of recent images taken of Saturn's most explosive moon indicate that they do. This form of asymmetric tectonic activity, very unusual on Earth, likely holds clues to the internal structure of Enceladus, which may contain subsurface seas where life might be able to develop. Pictured above is a composite of 28 images taken by the robotic Cassini spacecraft in October just after swooping by the ice-spewing orb. Inspection of these images show clear tectonic displacements where large portions of the surface all appear to move all in one direction. Near the top of the image appears one of the most prominent tectonic divides: Labtayt Sulci, a canyon about one kilometer deep.

APOD: 2008 November 5 - Seventeen Hundred Kilometers Above Enceladus
Explanation: Above is one of the closest pictures yet obtained of Saturn's ice-spewing moon Enceladus. The image was taken from about 1,700 kilometers up as the robotic Cassini spacecraft zoomed by the fractured ice ball last week. Features the size of a bus are resolvable in this highly detailed image taken of Enceladus' active tiger stripe region. Very different from most other moons and planets, grooves and hills dot an alien moonscape devoid of craters. Space pioneers might wonder where, on such a highly textured surface, a future probe might land in search of freshly deposited ice, subsurface seas, or even indicators of life. Although appearing dark in the above contrast-enhanced image, the surface of Enceladus is covered with some of the brightest ice in the entire Solar System, reflecting about 99 percent of the light it receives. To help better understand this enigmatic world, Cassini is scheduled to swoop by Enceladus at least five more times.

APOD: 2008 October 14 - An Enceladus Tiger Stripe from Cassini
Explanation: What creates the unusual tiger stripes on Saturn's moon Enceladus? No one is sure. To help find out, scientists programmed the robotic Cassini spacecraft to dive right past the plume-spewing moon last week. Previously, the tiger stripe regions were found to be expelling plumes of water-ice, fueling speculation that liquid seas might occur beneath Enceladus' frozen exterior. Such seas are so interesting because they are candidates to contain extraterrestrial life. Important processes in tiger stripe formation may include heating from below and moonquakes. Visible above is terrain on Enceladus so young that only a few craters are visible. This newly released raw image shows at least one type of false artifact, however, as seeming chains of craters are not so evident in other concurrently released images of the same region. The large tiger stripe across the image middle is impressive not only for its length and breadth, but because a large internal shadow makes it also appear quite deep. Cassini will next fly by Enceladus on October 31.

APOD: 2008 October 13 - Cassini Passes Through Ice Plumes of Enceladus
Explanation: What telling impurities taint the ice plumes of Enceladus? To help answer this question, the robotic Cassini spacecraft dove last week to within 30 kilometers of Saturn's ice-plume emitting moon. At this closest-ever approach, Cassini attempted to sniff and obtain chemical data on particles ejected from Enceladus' regular surface, while at other times Cassini flew right through -- and sampled -- ice geysers directly. Searches in the data for impurity clues in the water-ice dominated plumes and surface ejecta are progressing. Although the main purpose of this flyby was particle analysis, several interesting images are emerging. Visible in the above image, for example, is an unusual gray sheen running vertically up the image center that might be water vapor escaping from surface canyons. Other notable features visible above include vast plains of craterless icy grooves, the day-night terminator across the image left, and an area near the top comparatively rich in craters. Cassini is scheduled to buzz by Enceladus in an imaging run near the end of this month.

APOD: 2008 July 20 - Crescent Rhea Occults Crescent Saturn
Explanation: Soft hues, partially lit orbs, a thin trace of the ring, and slight shadows highlight this understated view of the majestic surroundings of the giant planet Saturn. Looking nearly back toward the Sun, the robot Cassini spacecraft now orbiting Saturn captured crescent phases of Saturn and its moon Rhea in color a few years ago. As striking as the above image is, it is but a single frame from a recently released 60-frame silent movie where Rhea can be seen gliding in front of its parent world. Since Cassini was nearly in the plane of Saturn's rings, the normally impressive rings are visible here only as a thin line across the image center. Although Cassini has now concluded its primary mission, its past successes and opportunistic location have prompted NASA to start a two-year Equinox Mission, further exploring not only Saturn's enigmatic moons Titan and Enceladus, but Saturn herself as her grand rings tilt right at the Sun in August 2009.

APOD: 2008 March 31 - Close Up of Enceladus Tiger Stripes
Explanation: Could life exist beneath Enceladus? A recent flyby of Saturn's icy moon has bolstered this fascinating idea. Two years ago, images from the robotic Cassini spacecraft orbiting Saturn led astronomers to the undeniable conclusion that Saturn's moon Enceladus was spewing fountains of gas and ice crystals through cracks in its surface dubbed tiger stripes. Last month, Cassini dove through some of these plumes and determined that they contained water vapor laced with small amounts of methane as well as simple and complex organic molecules. Surprisingly, the plumes of Enceladus appear similar in make-up to many comets. What's more, the temperature and density of the plumes indicate they might have originated from a warmer source -- possibly a liquid source -- beneath the surface. A liquid water sea containing organic molecules is a good place to look for life. Pictured above is a vertically exaggerated close-up of some long, venting tiger stripes. The computer composite was generated from images and shadows taken during recent Cassini flybys. Nine more flybys of Enceladus by Cassini are planned.

APOD: 2008 March 17 - Thirty Thousand Kilometers Above Enceladus
Explanation: What does the surface of Saturn's ice-spewing moon Enceladus look like? To help find out, the robotic Cassini spacecraft now orbiting Saturn was sent soaring past the cryovolcanic moon and even right through one of Enceladus' ice plumes. Cassini closed to about 52 kilometers during its closest encounter to date. The above unprocessed image was taken looking down from the north, from about 30,000 kilometers away. Visible are at least two types of terrain. The first type of terrain has more craters than occur near Enceladus' South Pole. The other type of terrain has few craters but many ridges and grooves that may have been created by surface-shifting tectonic activity. Exogeologists are currently poring over this and other Cassini images from last Wednesday's flyby to better understand the moon's patch-work surface, its unusual ice-geysers, and its potential to support life. Cassini is scheduled to fly by Enceladus at least nine more times, including an even closer pass of just 25 kilometers this coming October.

APOD: 2007 December 17 - Saturn's Ancient Rings
Explanation: How old are Saturn's rings? No one is quite sure. One possibility is that the rings formed relatively recently in our Solar System's history, perhaps only about 100 million years ago when a moon-sized object broke up near Saturn. Evidence for a young ring age includes a basic stability analysis for rings, and the fact that the rings are so bright and relatively unaffected by numerous small dark meteor impacts. New evidence, however, raises the possibility that some of Saturn's rings may be billions of years old and so almost as old as Saturn itself. Inspection of images by the Saturn-orbiting Cassini spacecraft indicates that some of Saturn's ring particles temporarily bunch and collide, effectively recycling ring particles by bringing fresh bright ices to the surface. Seen here, Saturn's rings were imaged in their true colors by the robotic Cassini in late October. Icy bright Tethys, a moon of Saturn likely brightened by a sandblasting rain of ice from sister moon Enceladus, is visible in front of the darker rings.

APOD: 2007 October 13 - Enceladus Ice Geysers
Explanation: Ice geysers erupt on Enceladus, bright and shiny inner moon of Saturn. Shown in this false-color image, a backlit view of the moon's southern limb, the majestic, icy plumes were discovered by instruments on the Cassini Spacecraft during close encounters with Enceladus in November of 2005. Eight source locations for these geysers have now been identified along substantial surface fractures in the moon's south polar region. Researchers suspect the geysers arise from near-surface pockets of liquid water with temperatures near 273 kelvins (0 degrees C). That's hot when compared to the distant moon's surface temperature of 73 kelvins (-200 degrees C). The cryovolcanism is a dramatic sign that tiny, 500km-diameter Enceladus is surprisingly active. Enceladus ice geysers also likely produce Saturn's faint but extended E ring.

APOD: 2007 March 27 - Enceladus Creates Saturns E Ring
Explanation: The active moon Enceladus appears to be making Saturn's E ring. An amazing picture showing the moon at work was taken late last year by the Saturn-orbiting Cassini spacecraft and is shown above. Enceladus is the dark spot inside the bright flare, right near the center of Saturn's E ring. Streams of ice and water vapor can be seen pouring off Enceladus into the E ring. The above bright image of the normally faint E-ring was made possible by aligning Cassini so that Saturn blocked the Sun. From that perspective, small ring particles reflect incoming sunlight more efficiently. Cassini has now been orbiting Saturn for almost three years, and is scheduled to swoop by the unexpectedly cryovolcanic Enceladus at least several more times.

APOD: 2007 January 31 - Movie: Cassini Crosses Saturn's Ring Plane
Explanation: What would the rings of Saturn look like if you passed right through the ring plane? To find out, NASA aimed cameras from the Cassini spacecraft right at Saturn's rings as the robotic explorer passed from the sunlit side of the rings to the shadowed side. Resulting images from a vantage point outside the rings and most moons, but inside the orbit of Titan, have been gathered together in the above time-lapse movie. The dramatic movie demonstrates that ring particle density and reflectivity makes some parts of the shadowed side nearly the photographic negative of the sunlit side, but nearly empty regions remain continually dark. Visible also are Saturn-orbiting moons Enceladus, Mimas, Janus, Epimetheus, Prometheus, and Pandora. The extreme thinness of Saturn's rings can be appreciated from frames taken near the crossing time.

APOD: 2006 December 31 - A Year of Extraterrestrial Fountains and Flows
Explanation: The past year was extraordinary for the discovery of extraterrestrial fountains and flows -- some offering new potential in the search for liquid water and the origin of life beyond planet Earth.. Increased evidence was uncovered that fountains spurt not only from Saturn's moon Enceladus, but from the dunes of Mars as well. Lakes were found on Saturn's moon Titan, and the residual of a flowing liquid was discovered on the walls of Martian craters. The diverse Solar System fluidity may involve forms of slushy water-ice, methane, or sublimating carbon dioxide. Pictured above, the light-colored path below the image center is hypothesized to have been created sometime in just the past few years by liquid water flowing across the surface of Mars.

APOD: 2006 October 16 - In the Shadow of Saturn
Explanation: In the shadow of Saturn, unexpected wonders appear. The robotic Cassini spacecraft now orbiting Saturn recently drifted in giant planet's shadow for about 12 hours and looked back toward the eclipsed Sun. Cassini saw a view unlike any other. First, the night side of Saturn is seen to be partly lit by light reflected from its own majestic ring system. Next, the rings themselves appear dark when silhouetted against Saturn, but quite bright when viewed away from Saturn and slightly scattering sunlight, in the above exaggerated color image. Saturn's rings light up so much that new rings were discovered, although they are hard to see in the above image. Visible in spectacular detail, however, is Saturn's E ring, the ring created by the newly discovered ice-fountains of the moon Enceladus, and the outermost ring visible above. Far in the distance, visible on the image left just above the bright main rings, is the almost ignorable pale blue dot of Earth.

APOD: 2006 June 27 - The Moving Moons of Saturn
Explanation: The moons of Saturn never stop. A space traveler orbiting the ringed giant planet would witness a continuing silent dance where Saturn's multiple moons pass near each other in numerous combinations. Like a miniature Solar System, the innermost moons orbit Saturn the fastest. The above movie was centered on Saturn's moon Rhea, so that the moons Mimas and Enceladus appear to glide by. At 1,500 kilometers across, Rhea is over three times larger than the comparably sized Mimas and Enceladus. The Sun illuminates the scene from the lower right, giving all of the moons the same crescent phase. The above time lapse movie was created by the Saturn-orbiting robotic Cassini spacecraft over a period of about 40 minutes.

APOD: 2006 June 8 - Enceladus Ice Volcanos
Explanation: In this stunning Saturnian vista - one in a series of artist's visions of volcanos on alien worlds - icy geysers erupt along narrow fractures in inner moon Enceladus. The majestic plumes were actually discovered by instruments on the Cassini Spacecraft during close encounters with bright and shiny Enceladus last year. Researchers now suspect the plumes originate from near-surface pockets of liquid water with temperatures near 273 kelvins (0 degrees C) - hot when compared to the distant moon's surface temperature of 73 kelvins (-200 degrees C). A dramatic sign that tiny, 500km-diameter Enceladus is surprisingly active, these ice volcanos hold out another potential site in the search for water and origin of life beyond planet Earth. Enceladus' ice volcanos also likely produce Saturn's faint but extended E ring.

APOD: 2006 May 3 - Saturn in Blue and Gold
Explanation: Why is Saturn partly blue? The above picture of Saturn approximates what a human would see if hovering close to the giant ringed world. The above picture was taken in mid-March by the robot Cassini spacecraft now orbiting Saturn. Here Saturn's majestic rings appear directly only as a thin vertical line. The rings show their complex structure in the dark shadows they create on the image left. Saturn's fountain moon Enceladus, only about 500 kilometers across, is seen as the bump in the plane of the rings. The northern hemisphere of Saturn can appear partly blue for the same reason that Earth's skies can appear blue -- molecules in the cloudless portions of both planet's atmospheres are better at scattering blue light than red. When looking deep into Saturn's clouds, however, the natural gold hue of Saturn's clouds becomes dominant. It is not known why southern Saturn does not show the same blue hue -- one hypothesis holds that clouds are higher there. It is also not known why Saturn's clouds are colored gold.

APOD: 2006 March 22 - Enceladus Near Saturn
Explanation: Some images of Saturn appear surreal. Earlier this year, the robot spacecraft Cassini now orbiting Saturn took this surreal image of the gas giant Saturn, its majestic rings, and its enigmatic world Enceladus all in one frame. Enceladus, recently found to emit jets of ice from possible underground seas, appears white as its surface is covered with relatively clean water-ice. Below Enceladus are the rings of Saturn, seen nearly edge on. Compared to Enceladus, Saturn's rings show their comparatively high density of dirt with their golden-brown color in this natural color image. The planet Saturn, in the background, appears relatively featureless with the exception of thin ring shadows visible on the upper left. The terminator between night and day is seen vertically across the face of this distant world.

APOD: 2006 March 10 - Enceladus and the Search for Water
Explanation: Based on data from Cassini spacecraft instruments, researchers are now arguing that liquid water reservoirs exist only tens of meters below the surface of Saturn's small (500 kilometer diameter) but active moon Enceladus. The exciting new results center around towering jets and plumes of material erupting from the moon's surface. The plumes originate in the long tiger stripe fractures of the south polar region pictured here. Detailed models suport conclusions that the plumes arise from near-surface pockets of liquid water at temperatures of 273 kelvins (0 degrees Celsius), even though Enceladus has a surface temperature of about 73 kelvins (-200 degrees Celsius). Clearly an important step in the search for water and the potential for the origin of life beyond planet Earth, such near-surface reservoirs of water would be far more accessible than, for example, the internal ocean detected on the Jovian moon Europa.

APOD: 2005 December 19 - Thin Rings Around Polarized Saturn
Explanation: How thin are the rings of Saturn? Brightness measurements from different angles have shown Saturn's rings to be about one kilometer thick, making them many times thinner, in relative proportion, than a razor blade. This thinness sometimes appears in dramatic fashion during an image taken nearly along the ring plane. The robot Cassini spacecraft now orbiting Saturn has now captured another shot that dramatically highlights the ring's thinness. The above artistic looking image was taken early last month in infrared polarized light. If alone in space, the unlit part of Saturn would be much darker. Reflection of light off of moons like Enceladus (pictured) and the billions of small particles in Saturn's rings, however, gives the giant space orb an unusual glow, an effect highlighted in polarized light.

APOD: 2005 December 5 - Ice Fountains Discovered on Saturns Enceladus
Explanation: Fountains of ice shoot out from Saturn's moon Enceladus. Clear discovery images of the fountains were made using observations from the robot Cassini spacecraft currently orbiting Saturn. During a recent pass, Cassini was programmed to look back toward the Sun where Enceladus would appear as a thin crescent. From this vantage point, particles emitted from the surface would better show themselves by reflecting sunlight. The tactic was successful -- the above frame shows several plumes emanating from regions previously known to contain gashes in the surface dubbed tiger stripes. Cassini detected an increase in particle emissions from these regions during a July flyby. Some of these ice particles likely contribute to the make up of Saturn's mysterious E ring.

APOD: 2005 September 6 - Fresh Tiger Stripes on Saturns Enceladus
Explanation: The tiger stripes on Saturn's moon Enceladus might be active. Even today, they may be spewing ice from the moon's icy interior into space, creating a cloud of fine ice particles over the moon's South Pole and creating Saturn's mysterious E-ring. Recent evidence for this has come from the robot Cassini spacecraft now orbiting Saturn. Cassini detected a marked increase in particle collisions during its July flyby only 270 kilometers over a South Polar region of Enceladus. Pictured above, a high resolution image of Enceladus is shown from the close flyby. The unusual surface features dubbed tiger stripes are visible on the left in false-color blue. Why Enceladus is active remains a mystery, as the neighboring moon Mimas, approximately the same size, appears quite dead.

APOD: 2005 June 6 - Saturn: Dirty Rings and a Clean Moon
Explanation: Eating surface ice from Enceladus might be healthier than eating ice from Saturn's rings -- it certainly appears cleaner. From their apparent densities and reflectance properties, both the rings of Saturn and its shiniest moon, Enceladus, are thought to be composed predominantly of water ice. For reasons that are not yet understood, however, many of Saturn's ring particles have become partly coated with some sort of relatively dark dust, while the surface of Enceladus appears comparatively bright and clean. The contrast between the two can be seen in the above image taken last month by the robot Cassini spacecraft now in orbit around Saturn. Bright Enceladus shines in the background in contrast to the darker foreground rings. The reason why Enceladus is so bright is currently unknown but might involve bringing fresh water to its surface with water volcanoes.

APOD: 2005 April 18 - Saturnian Moon and Rings
Explanation: When can a robot produce art? When it glides past the rings of Saturn. As the robot spacecraft Cassini orbiting Saturn crossed outside the famous photogenic ring plane of the expansive planet, the rings were imaged from the outside, nearly edge on, and in the shadow of Saturn. From the upper left, ring features include the A ring, the Cassini gap, the B ring, and the darker C ring that includes the Titan gap and a gap yet unnamed. Last month when the above image was taken, the gliding spacecraft was about one million kilometers from foreground Enceladus, a small Saturnian moon only about 500 kilometers across. Cassini is scheduled to continue its 70 orbit tour of Saturn over the next three years, sending back images of the gas giant, its rings, and its moons that will be studied for decades to come.

APOD: 2005 March 17 - Enceladus Close Up
Explanation: The surface of Enceladus is as white as fresh snow. Still, an impressive variety of terrain is revealed in this contrast enhanced image. At a resolution of about 30 meters per pixel, the close-up view spans over 20 kilometers - recorded during the touring Cassini spacecraft's March flyby of the icy Saturnian moon. Enceladus is known to be the most reflective moon in the solar system, and the recent Cassini encounters have also detected the presence of an atmosphere, making Enceladus the second moon of Saturn with such a distinction. In fact, Enceladus' fresh looking surface and significant atmosphere both indicate that the tiny, 500 kilometer diameter moon is active. Researchers suspect that ice volcanos or geysers coat the surface with fresh material and replenish the moon's atmosphere, ultimately providing the icy particles that compose Saturn's tenuous E ring.

APOD: 2005 February 24 - Ski Enceladus
Explanation: Small, icy, inner moon of Saturn, Enceladus is only about 500 kilometers in diameter. But the distant world does reflect over 90 percent of the sunlight it receives, giving its surface about the same reflectivity as fresh snow. Seen here in a sharp view from the Cassini spacecraft's recent flyby, Enceladus shows a variety of surface features and very few impact craters - indicating that it has been an active world even though this tiny moon should have completely cooled off long ago. In fact, the resurfaced appearance of Enceladus could be the result of liquid water geysers or water volcanos. Since Enceladus orbits within the outer E ring of Saturn, the moon's surface may be kept snow-bright as it is continuously bombarded with icy ring particles. Eruptions on Enceladus itself would in turn supply material to the E ring. Interplanetary ski bums take note: tiny Enceladus has only about 1/100th the surface gravity of planet Earth and a surface temperature of -200 degrees C (-330 degrees F).

APOD: 2003 August 17 - Natural Saturn On The Cassini Cruise
Explanation: What could you see approaching Saturn aboard an interplanetary cruise ship? Your view would likely resemble this subtly shaded image of the gorgeous ringed gas giant. Processed by the Hubble Heritage project, the picture intentionally avoids overemphasizing color contrasts and presents a natural looking Saturn with cloud bands, storms, nearly edge-on rings, and the small round shadow of the moon Enceladus near the center of the planet's disk. Of course, seats were not available on the only ship currently en route, the Cassini spacecraft. Cassini flew by Jupiter at the turn of the millennium and is scheduled to arrive at Saturn in the year 2004. After an extended cruise to a world 1,400 million kilometers from the Sun, Cassini will tour the Saturnian system, conducting a remote, robotic exploration with software and instruments designed by denizens of planet Earth.

APOD: 2002 May 11 - Natural Saturn On The Cassini Cruise
Explanation: What could you see approaching Saturn aboard an interplanetary cruise ship? Your view would likely resemble this subtly shaded image of the gorgeous ringed gas giant. Processed by the Hubble Heritage project, the picture intentionally avoids overemphasizing color contrasts and presents a natural looking Saturn with cloud bands, storms, nearly edge-on rings, and the small round shadow of the moon Enceladus near the center of the planet's disk. Of course, seats were not available on the only ship currently enroute, the Cassini spacecraft. Cassini flew by Jupiter at the turn of the millennium and is scheduled to arrive at Saturn in the year 2004. After an extended cruise to a world 1,400 million kilometers from the Sun, Cassini will tour the Saturnian system, conducting a remote, robotic exploration with software and instruments designed by denizens of planet Earth.

APOD: 2002 January 24 - Ski Enceladus
Explanation: A small inner moon of Saturn, Enceladus is only about 500 kilometers in diameter. But the cold, distant world does reflect over 90 percent of the sunlight it receives, giving its surface about the same reflectivity as new-fallen snow. Seen here in a mosaic of Voyager 2 images from 1981, Enceladus shows a variety of surface features and very few impact craters - indicating that it is an active world even though this ice moon should have completely cooled off long ago. In fact the fresh, resurfaced appearance of Enceladus suggests that an internal mechanism, perhaps driven by tidal pumping, generates heat and supplies liquid water to geysers or water volcanos. Since Enceladus orbits within the tenuous outer E ring of Saturn, the moon's surface may be kept snow-bright as it is continuously bombarded with icy ring particles. Eruptions on Enceladus itself would in turn supply material to the E ring. Interplanetary ski bums take note: tiny Enceladus has only about one hundredth the surface gravity of planet Earth.

APOD: 2000 January 29 - Natural Saturn On The Cassini Cruise
Explanation: What could you see approaching Saturn aboard an interplanetary cruise ship? Your view would likely resemble this subtly shaded image of the gorgeous ringed gas giant. Processed by the Hubble Heritage project, the picture intentionally avoids overemphasizing color contrasts and presents a natural looking Saturn with cloud bands, storms, nearly edge-on rings, and the small round shadow of the moon Enceladus near the center of the planet's disk. Of course, seats were not available on the only ship currently enroute - the Cassini spacecraft, launched in 1997 and scheduled to arrive at Saturn in the year 2004. After an extended cruise to a world 1,400 million kilometers from the Sun, Cassini will tour the Saturnian system, conducting a remote, robotic exploration with software and instruments designed by denizens of planet Earth. But where is Cassini now? Still about 980 million kilometers from Saturn, last Sunday the spacecraft flew by asteroid 2685 Masursky.

APOD: November 5, 1998 - Natural Saturn On The Cassini Cruise
Explanation: What you could see approaching Saturn aboard an interplanetary cruise ship would closely resemble this subtly shaded view of the gorgeous ringed gas giant. Processed by the Hubble Heritage project, the picture intentionally avoids overemphasizing color contrasts and presents a natural looking Saturn with cloud bands, storms, nearly edge-on rings, and the small round shadow of the moon Enceladus near the center of the planet's disk. Of course, seats were not available on the only ship currently enroute - the Cassini spacecraft, launched just over a year ago and scheduled to arrive at Saturn in the year 2004. After an extended cruise to a world 1,400 million kilometers from the Sun, Cassini will tour the Saturnian system, conducting a remote, robotic exploration with software and instruments designed by denizens of planet Earth.

APOD: October 18, 1998 - Saturns Rings Seen Sideways
Explanation: Saturn's rings are actually very thin. This picture from the Hubble Space Telescope was taken on August 6, 1995 when the rings lined up sideways as seen from Earth. Saturn's largest moon Titan is seen on the left, and Titan's shadow can be seen on Saturn's cloud tops! Titan itself looks a brownish color because of its thick atmosphere. Four other moons of Saturn can be seen just above the ring plane, which are, from left to right: Mimas, Tethys, Janus, and Enceladus. If you look carefully, you will note that the dark band across the planet is actually the shadow of the rings, and is slightly displaced from the real rings - which are best seen away from the planet. Saturn's rings are not solid - they are composed of ice chunks which range in size from a grain of sand to a house.

APOD: May 24, 1997 - Saturn's Rings Seen Sideways
Explanation: Saturn's rings are actually very thin. This picture from the Hubble Space Telescope was taken on August 6, 1995 when the rings lined up sideways as seen from Earth. Saturn's largest moon Titan is seen on the left, and Titan's shadow can be seen on Saturn's cloud tops! Titan itself looks a brownish color because of its thick atmosphere. Four other moon's of Saturn can be seen just above the ring plane, which are, from left to right: Mimas, Tethys, Janus, and Enceladus. If you look carefully, you will note that the dark band across the planet is actually the shadow of the rings, and is slightly displaced from the real rings - which are best seen away from the planet. Saturn's rings are not solid - they are composed of ice chunks which range in size from a grain of sand to a house.

APOD: April 29, 1996 - Saturn's Rings Seen Sideways
Explanation: Saturn's rings are actually very thin. This picture from the Hubble Space Telescope was taken on August 6, 1995 when the rings lined up sideways as seen from Earth. Saturn's largest moon Titan is seen on the left, and Titan's shadow can be seen on Saturn's cloud tops! Titan itself looks a brownish color because of its thick atmosphere. Four other moon's of Saturn can be seen just above the ring plane, which are, from left to right: Mimas, Tethys, Janus, and Enceladus. If you look carefully, you will note that the dark band across the planet is actually the shadow of the rings, and is slightly displaced from the real rings - which are best seen away from the planet. Saturn's rings are not solid - they are composed of ice chunks which range in size from a grain of sand to a house.

APOD: November 25, 1995 - Saturn's Cleanest Moon: Enceladus
Explanation: Enceladus orbits Saturn between the smaller Mimas and the larger Tethys. Enceladus is composed mostly of water ice and has the cleanest and purest ice surface in the Solar System. It's surface therefore appears nearly white. The surface also has many unusual groves and relatively few craters, like Jupiter's moon Ganymede. This indicates that the surface is young and/or newly reformed. To explain this, some astronomers speculate that Enceladus is susceptible to some sort of volcanic activity. Enceladus was originally discovered in 1789 by William Herschel.