Showing posts with label Saturn. Show all posts
Showing posts with label Saturn. Show all posts

Thursday, December 10, 2015

Dione and Enceladus as seen by Cassini

Dione and Enceladus as seen by Cassini
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Although Dione (near) and Enceladus (far) are composed of nearly the same materials, Enceladus has a considerably higher reflectivity than Dione. As a result, it appears brighter against the dark night sky. The surface of Enceladus (504 kilometers across) endures a constant rain of ice grains from its south polar jets. As a result, its surface is more like fresh, bright, snow than Dione's (1123 kilometers across) older, weathered surface. As clean, fresh surfaces are left exposed in space, they slowly gather dust and radiation damage and darken in a process known as "space weathering". This view looks toward the leading hemisphere of Enceladus. North on Enceladus is up and rotated 1 degree to the right. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Sept. 8, 2015. The view was acquired at a distance of approximately 83,000 kilometers from Dione. Image scale is 500 meters per pixel. The distance from Enceladus was 364,000 kilometers for an image scale of 2.2 kilometers per pixel. The Cassini mission is a cooperative project of NASA, ESA (the European Space Agency) and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colorado.
Image Credit: NASA/JPL-Caltech/Space Science Institute
Image enhancement: Jean-Baptiste Faure

Sunday, December 25, 2011

A view of Saturn and its Rings, Enceladus and Epimetheus!

A view of Saturn and its Rings, Enceladus and Epimetheus!
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A pair of Saturn's moons appear insignificant compared to the immensity of the planet in this Cassini spacecraft view along the terminator where day transitions to night. The larger moon Enceladus (504 kilometers, or 313 miles across) is also on the left, just a bit closer to the center of the image. Epimetheus (113 kilometers, or 70 miles across) appears as a tiny black speck on the far left of the image, left of Enceladus, just below the thin line of the rings. The rings cast wide shadows on the southern hemisphere of the planet. This view looks toward the northern, sunlit side of the rings from just above the ringplane. The image was taken with the Cassini spacecraft wide-angle camera on Nov. 4, 2011 using a spectral filter sensitive to wavelengths of near-infrared light centered at 752 nanometers. The view was acquired at a distance of approximately 1.2 million kilometers (746,000 miles) from Saturn and roughly 1 million kilometers (600,000 miles) from Enceladus and Epimetheus. Image scale is about 75 kilometers (47 miles) per pixel on Saturn, 60 kilometers (37 miles) per pixel on Enceladus and 66 kilometers (41 miles) per pixel on Epimetheus.
Credit: NASA/JPL-Caltech/Space Science Institute

Sunday, November 20, 2011

Saturn's geyser moon Enceladus as seen by NASA's Cassini

Saturn's geyser moon Enceladus as seen by NASA's Cassini
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NASA's Cassini spacecraft successfully completed its Oct. 1 flyby of Saturn's moon Enceladus and its jets of water vapor and ice. At its closest approach, the spacecraft flew approximately 62 miles (100 kilometers) above the moon's surface. The close approach was designed to give some of Cassini's instruments, including the ion and neutral mass spectrometer, the chance to "taste" the jets themselves. At a higher vantage point during the encounter, Cassini's high-resolution camera captured pictures of the jets emanating from the moon's south polar region. The images of the surface include previously seen leading-hemisphere terrain. However, during this encounter, multi-spectral imaging of these terrains extended farther into the ultraviolet region of the electromagnetic spectrum than had previously been achieved at this resolution. By looking at the surface at ultraviolet wavelengths, scientists can better detect the difference between surface materials and shadows than they can at visible wavelengths, where icy materials are highly reflective and shadows are washed out. With both ultraviolet and visible images of the same terrain available to them, scientists will better understand how the surface coverage of icy particles coming from the vents and plumes changes with terrain type and age. Cassini's next pass of this fascinating moon will be Oct. 19, when the spacecraft flies by at an altitude of approximately 765 miles (1231 kilometers).
Credit: NASA/JPL-Caltech/Space Science Institute

Friday, November 4, 2011

A crescent Saturn nestled within encircling Rings!

A crescent Saturn nestled within encircling Rings!
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A crescent Saturn appears nestled within encircling rings in this Cassini spacecraft image. Clouds swirl through the atmosphere of the planet. Prometheus (86 kilometers, or 53 miles across) orbits between the main rings and the thin F ring, and this moon appears as a speck above the rings near the middle of the image. This view looks toward the southern, unilluminated side of the rings from about 3 degrees below the ringplane. The image was taken with the Cassini spacecraft wide-angle camera on Sept. 14, 2010 using a spectral filter sensitive to wavelengths of near-infrared light centered at 890 nanometers. The view was obtained at a distance of approximately 2.6 million kilometers (1.6 million miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 100 degrees. Image scale on Saturn is 151 kilometers (94 miles) per pixel.
Credit: NASA/JPL/Space Science Institute

Cassini spacecraft views Saturn's Rings as never before!

Cassini spacecraft views Saturn's Rings as never before!
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With giant Saturn hanging in the blackness and sheltering Cassini from the sun's blinding glare, the spacecraft viewed the rings as never before, revealing previously unknown faint rings and even glimpsing its home world. This marvelous panoramic view was created by combining a total of 165 images taken by the Cassini wide-angle camera over nearly three hours on Sept. 15, 2006. The full mosaic consists of three rows of nine wide-angle camera footprints; only a portion of the full mosaic is shown here. Color in the view was created by digitally compositing ultraviolet, infrared and clear filter images and was then adjusted to resemble natural color. The mosaic images were acquired as the spacecraft drifted in the darkness of Saturn's shadow for about 12 hours, allowing a multitude of unique observations of the microscopic particles that compose Saturn's faint rings. Ring structures containing these tiny particles brighten substantially at high phase angles: i.e., viewing angles where the sun is almost directly behind the objects being imaged. During this period of observation Cassini detected two new faint rings: one coincident with the shared orbit of the moons Janus and Epimetheus, and another coincident with Pallene's orbit.
The narrowly confined G ring is easily seen here, outside the bright main rings. Encircling the entire system is the much more extended E ring. The icy plumes of Enceladus, whose eruptions supply the E ring particles, betray the moon's position in the E ring's left-side edge. Interior to the G ring and above the brighter main rings is the pale dot of Earth. Cassini views its point of origin from over a billion kilometers (and close to a billion miles) away in the icy depths of the outer solar system. Small grains are pushed about by sunlight and electromagnetic forces. Hence, their distribution tells much about the local space environment. A second version of the mosaic view is presented here in which the color contrast is greatly exaggerated. In such views, imaging scientists have noticed color variations across the diffuse rings that imply active processes sort the particles in the ring according to their sizes. Looking at the E ring in this color-exaggerated view, the distribution of color across and along the ring appears to be different between the right side and the left. Scientists are not sure yet how to explain these differences, though the difference in phase angle between right and left may be part of the explanation. The phase angle is about 179 degrees on Saturn. The main rings are overexposed in a few places. This view looks toward the unlit side of the rings from about 15 degrees above the ringplane. Cassini was approximately 2.2 million kilometers (1.3 million miles) from Saturn when the images in this mosaic were taken. Image scale on Saturn is about 260 kilometers (162 miles) per pixel.
Credit: NASA/JPL/Space Science Institute

Sunday, September 25, 2011

Water vapor and ice erupt from Saturn's moon Enceladus!

Water vapor and ice erupt from Saturn's moon Enceladus!
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Water vapor and ice erupt from Saturn's moon Enceladus, the source of a newly discovered donut-shaped cloud around Saturn. The small, dynamic moon spews out dramatic plumes of water vapor and ice - first seen by NASA's Cassini spacecraft in 2005. It possesses simple organic particles and may house liquid water beneath its surface. Its geyser-like jets create a gigantic halo of ice, dust and gas around Enceladus that helps feed Saturn's E ring. Now, thanks again to those icy jets, Enceladus is the only moon in our solar system known to influence substantially the chemical composition of its parent planet. In June, the European Space Agency announced that its Herschel Space Observatory, which has important NASA contributions, had found a huge donut-shaped cloud, or torus, of water vapor created by Enceladus encircling Saturn. The torus is more than 373,000 miles (600,000 kilometers) across and about 37,000 miles (60,000 kilometers) thick. It appears to be the source of water in Saturn's upper atmosphere.
Credit: NASA/JPL-Caltech/Space Science Institute

Thursday, June 16, 2011

Striking view of Saturn embraced by the shadows of its Rings

Striking view of Saturn embraced by the shadows of its Rings
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Few sights in the solar system are more strikingly beautiful than softly hued Saturn embraced by the shadows of its stately rings. The gas planet's subtle northward gradation from gold to azure is a striking visual effect that scientists don't fully understand. Current thinking says that it may be related to seasonal influences, tied to the cold temperatures in the northern (winter) hemisphere. Despite Cassini's revelations, Saturn remains a world of mystery. Currently, the rings' shadows shield the mid-northern latitudes from the harshest of the sun's rays. As Saturn travels around the sun in its 29-year orbit, the shadows will narrow and head southward, eventually blanketing the opposite hemisphere. Images taken with blue, green and red spectral filters were used to create this color view, which approximates the scene as it would appear to the human eye. The view was brightened to enhance detail visible in the rings and within their shadows. The images were obtained with the Cassini wide-angle camera from a distance of approximately 999,000 kilometers (621,000 miles) from Saturn on May 4, 2005, as the spacecraft cruised a few degrees above the ring plane. The image scale is about 60 kilometers (37 miles) per pixel on Saturn.
Credit: NASA/JPL/Space Science Institute

Tuesday, May 17, 2011

NASA's Cassini spacecraft's view of Golden Night on Saturn

NASA's Cassini spacecraft's view of Golden Night on Saturn
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Saturn's B and C rings shine in diffuse, scattered light as the Cassini spacecraft looks on the planet's night side. The southern hemisphere is lit by sunlight reflecting off the rings, while the north shines much more feebly in the dim light that filters through the rings and is scattered on the northern hemisphere. The fine, innermost rings are seen silhouetted against the southern hemisphere of the planet before partially disappearing into shadow. The color of the rings appears more golden because of the increased scattering in the rings brought about by the high phase angle and the view being toward rings' the unlit side. Saturn also looks more golden because of the high phase angle here.
Images taken using red, green and blue spectral filters were combined to create this natural color view. The images were obtained by the Cassini spacecraft wide-angle camera on Sept. 28, 2006 at a distance of approximately 1.4 million kilometers (900,000 miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 151 degrees. Image scale is 83 kilometers (51 miles) per pixel.
Credit: NASA/JPL/Space Science Institute

Monday, May 9, 2011

Cassini Orbiter view of Saturn and Rings: the Rite of Spring!

Cassini Orbiter view of Saturn and Rings: the Rite of Spring!
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Of the countless equinoxes Saturn has seen since the birth of the solar system, this one, captured here in a mosaic of light and dark, is the first witnessed up close by an emissary from Earth... none other than our faithful robotic explorer, Cassini. Seen from our planet, the view of Saturn's rings during equinox is extremely foreshortened and limited. But in orbit around Saturn, Cassini had no such problems. From 20 degrees above the ring plane, Cassini's wide angle camera shot 75 exposures in succession for this mosaic showing Saturn, its rings, and a few of its moons a day and a half after exact Saturn equinox, when the sun's disk was exactly overhead at the planet's equator. The novel illumination geometry that accompanies equinox lowers the sun’s angle to the ring plane, significantly darkens the rings, and causes out-of-plane structures to look anomalously bright and to cast shadows across the rings. These scenes are possible only during the few months before and after Saturn's equinox which occurs only once in about 15 Earth years. Before and after equinox, Cassini's cameras have spotted not only the predictable shadows of some of Saturn's moons, but also the shadows of newly revealed vertical structures in the rings themselves. Also at equinox, the shadows of the planet's expansive rings are compressed into a single, narrow band cast onto the planet as seen in this mosaic. The images comprising the mosaic, taken over about eight hours, were extensively processed before being joined together. First, each was re-projected into the same viewing geometry and then digitally processed to make the image "joints" seamless and to remove lens flares, radially extended bright artifacts resulting from light being scattered within the camera optics. At this time so close to equinox, illumination of the rings by sunlight reflected off the planet vastly dominates any meager sunlight falling on the rings. Hence, the half of the rings on the left illuminated by planetshine is, before processing, much brighter than the half of the rings on the right. On the right, it is only the vertically extended parts of the rings that catch any substantial sunlight. With no enhancement, the rings would be essentially invisible in this mosaic. To improve their visibility, the dark (right) half of the rings has been brightened relative to the brighter (left) half by a factor of three, and then the whole ring system has been brightened by a factor of 20 relative to the planet. So the dark half of the rings is 60 times brighter, and the bright half 20 times brighter, than they would have appeared if the entire system, planet included, could have been captured in a single image. The moon Janus (179 kilometers, 111 miles across) is on the lower left of this image. Epimetheus (113 kilometers, 70 miles across) appears near the middle bottom. Pandora (81 kilometers, 50 miles across) orbits outside the rings on the right of the image. The small moon Atlas (30 kilometers, 19 miles across) orbits inside the thin F ring on the right of the image. The brightnesses of all the moons, relative to the planet, have been enhanced between 30 and 60 times to make them more easily visible. Other bright specks are background stars. Spokes - ghostly radial markings on the B ring - are visible on the right of the image. This view looks toward the northern side of the rings from about 20 degrees above the ring plane. The images were taken on Aug. 12, 2009, beginning about 1.25 days after exact equinox, using the red, green and blue spectral filters of the wide angle camera and were combined to create this natural color view. The images were obtained at a distance of approximately 847,000 kilometers (526,000 miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 74 degrees. Image scale is 50 kilometers (31 miles) per pixel.
Credit: NASA/JPL/Space Science Institute

Friday, May 6, 2011

Quadruple Saturn moon transit snapped by Hubble's WFPC2

Quadruple Saturn moon transit snapped by Hubble's WFPC2
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This close-up view of Saturn's disc captures the transit of several moons across the face of the gas giant planet. The giant orange moon Titan - larger than the planet Mercury - can be seen at upper right. The white icy moons that are much closer to Saturn, hence much closer to the ring plane in this view, are, from left to right: Enceladus, Dione, and Mimas. The dark band running across the face of the planet slightly above the rings is the shadow of the rings cast on the planet. This picture was taken with Hubble's Wide Field Planetary Camera 2 (WFPC2) on 24 February 2009, when Saturn was at a distance of roughly 1.25 billion kilometres from Earth. Hubble can see details as small as 300 kilometres across on Saturn.
Credit: NASA, ESA and the Hubble Heritage Team (STScI/AURA)
Acknowledgment: M. Wong (STScI/UC Berkeley) and C. Go (Philippines)

Monday, March 21, 2011

Cassini spacecraft sees seasonal rains transform Titan's surface

Cassini spacecraft sees seasonal rains transform Titan's surface
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NASA's Cassini spacecraft chronicles the change of seasons as it captures clouds concentrated near the equator of Saturn's largest moon, Titan. Methane clouds in the troposphere, the lowest part of the atmosphere, appear white here and are mostly near Titan's equator. The darkest areas are surface features that have a low albedo, meaning they do not reflect much light. Cassini observations of clouds like these provide evidence of a seasonal shift of Titan's weather systems to low latitudes following the August 2009 equinox in the Saturnian system. During equinox, the sun lies directly over the equator. In 2004, during Titan's late southern summer, extensive cloud systems were common in Titan's south polar region. Since 2005, southern polar systems have been observed infrequently, and one year after the equinox, extensive near-equatorial clouds have been seen. This image was taken on Oct. 18, 2010, a little more than one Earth year after the Saturnian equinox, which happens once in roughly 15 Earth years.
The cloud patterns observed from late southern summer to early southern fall on Titan suggest that Titan's global atmospheric circulation is influenced by both the atmosphere and the surface. The temperature of the surface responds more rapidly to changes in illumination than does the thick atmosphere. Outbreaks such as the clouds seen here may be the Titan equivalent of what creates the Earth's tropical rainforest climates, even though the delayed reaction to the change of seasons and the apparently sudden shift is more reminiscent of the behavior over Earth's tropical oceans than over tropical land areas.
A few clouds can be seen in Titan's southern latitudes here. Some clouds are also visible in the high northern latitudes here. This view looks toward the Saturn-facing side of Titan (5,150 kilometers or 3,200 miles across). North is up. The image appears slightly grainy because it was re-projected to a scale of 6 kilometers (4 miles) per pixel. Scale in the original image was 15 kilometers (9 miles) per pixel.
This view consists of an average of three images taken using a filter sensitive to near-infrared light centered at 938 nanometers, which allows for detection of Titan's surface and lower atmosphere, plus an image taken using a filter sensitive to visible light centered at 619 nanometers.
The images were taken with the Cassini spacecraft's narrow-angle camera at a distance of approximately 2.5 million kilometers (1.6 million miles) from Titan and at a sun-Titan-spacecraft, or phase, angle of 56 degrees.
Credit: NASA/JPL/SSI

Monday, February 28, 2011

Huge storm on Saturn witnessed by the Cassini spacecraft!

Huge storm on Saturn witnessed by the Cassini spacecraft!
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The huge storm churning through the atmosphere in Saturn's northern hemisphere overtakes itself as it encircles the planet in this true-color view from NASA's Cassini spacecraft. This picture was taken about 12 weeks after the storm began, and the clouds by this time had formed a tail that wrapped around the planet. Some of the clouds moved south and got caught up in a current that flows to the east (to the right) relative to the storm head. This tail, which appears as slightly blue clouds south and west (left) of the storm head, can be seen encountering the storm head in this view. This storm is the largest, most intense storm observed on Saturn by NASA's Voyager or Cassini spacecraft. It is still active today. As scientists have tracked this storm over several months, they have found it covers 500 times the area of the largest of the southern hemisphere storms observed earlier in the Cassini mission (see PIA06197). The shadow cast by Saturn's rings has a strong seasonal effect, and it is possible that the switch to powerful storms now being located in the northern hemisphere is related to the change of seasons after the planet's August 2009 equinox. Huge storms called Great White Spots have been observed in previous Saturnian years (each of which is about 30 Earth years), usually appearing in late northern summer. Saturn is now experiencing early northern spring, so this storm, if it is a Great White Spot, is happening earlier than usual. This storm is about as large as the largest of the Great White Spots, which also encircled the planet but had latitudinal sizes ranging up to 20,000 kilometers (12,000 miles). The Voyager and Cassini spacecraft were not at Saturn for previous Great White Spot appearances. The storm is a prodigious source of radio noise, which comes from lightning deep in the planet's atmosphere. The lightning is produced in the water clouds, where falling rain and hail generate electricity. The mystery is why Saturn stores energy for decades and releases it all at once. This behavior is unlike that at Jupiter and Earth, which have numerous storms going on at all times. This view looks toward the sunlit side of the rings from just above the ring plane. Images taken using red, green and blue spectral filters were combined to create this natural color view. The images were acquired with the Cassini spacecraft wide-angle camera at a distance of approximately 1.4 million miles (2.2 million kilometers) from Saturn. Image scale is 80 miles (129 kilometers) per pixel.
Credit: NASA/JPL/Space Science Institute

Sunday, February 6, 2011

Smog-enshrouded Titan, Epimetheus and Saturn's A and F rings!

Smog-enshrouded Titan, Epimetheus and Saturn's A and F rings!
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Cassini delivers this stunning vista showing small, battered Epimetheus and smog-enshrouded Titan, with Saturn's A and F rings stretching across the scene. The color information in the colorized view is completely artificial: it is derived from red, green and blue images taken at nearly the same time and phase angle as the clear filter image. This color information was overlaid onto the previously released clear filter view in order to approximate the scene as it might appear to human eyes. The prominent dark region visible in the A ring is the Encke gap (325 kilometers wide), in which the moon Pan (26 kilometers across) and several narrow ringlets reside. Moon-driven features which score the A ring can easily be seen to the left and right of the Encke gap. A couple of bright clumps can be seen in the F ring. Epimetheus is 116 kilometers across and giant Titan is 5,150 kilometers across. The view was acquired with the Cassini spacecraft narrow-angle camera on April 28, 2006, at a distance of approximately 667,000 kilometers from Epimetheus and 1.8 million kilometers from Titan. The image captures the illuminated side of the rings. The image scale is 4 kilometers per pixel on Epimetheus and 11 kilometers per pixel on Titan.
Credit: NASA/JPL/Space Science Institute

Thursday, February 3, 2011

NASA's Cassini craft shoots the jets of Saturn's moon Enceladus

NASA's Cassini craft shoots the jets of Saturn's moon Enceladus
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On Jan. 31, 2011, NASA's Cassini spacecraft passed by several of Saturn's intriguing moons, snapping images along the way. Cassini passed within about 37,282 miles of Enceladus and 17,398 miles of Helene. It also caught a glimpse of Mimas in front of Saturn's rings. In this image, Cassini snapped a picture of the famous jets erupting from the south polar terrain of Enceladus.
Credit: NASA/JPL/SSI

Tuesday, January 18, 2011

NASA's Cassini spacecraft captures gigantic Saturn's storm

NASA's Cassini spacecraft captures gigantic Saturn's storm
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This spectacular image of a huge Saturn's storm was captured by NASA's Cassini spacecraft on January 15, 2011. The image was acquired through IR, Green, and Blue filters.
Credit: JPL/NASA

Thursday, January 6, 2011

The magic of illumination geometry: Saturn's rings and shadows

The magic of illumination geometry: Saturn's rings and shadows
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The shadows of Saturn's rings cast onto the planet appear as a thin band at the equator in this image taken as the planet approached its August 2009 equinox. The novel illumination geometry that accompanies equinox lowers the sun's angle to the ringplane, significantly darkens the rings, and causes out-of-plane structures to look anomalously bright and to cast shadows across the rings. These scenes are possible only during the few months before and after Saturn's equinox which occurs only once in about 15 Earth years. Before and after equinox, Cassini's cameras have spotted not only the predictable shadows of some of Saturn's moons, but also the shadows of newly revealed vertical structures in the rings themselves. For an earlier view of the rings' wide shadows draped high on the northern hemisphere. The planet's southern hemisphere can be seen through the transparent D ring in the lower right of the image. The rings have been brightened by a factor of 9.5 relative to the planet to enhance visibility. This view looks toward the northern, unilluminated side of the rings from about 30 degrees above the ringplane. Images taken using red, green and blue spectral filters were combined to create this natural color view. The images were obtained with the Cassini spacecraft wide-angle camera on July 18, 2009 at a distance of approximately 2.1 million kilometers (1.3 million miles) from Saturn. Image scale is 122 kilometers (76 miles) per pixel.
Credit: NASA/JPL/Space Science Institute

Wednesday, December 29, 2010

Elaborate image of Saturn's moon Rhea by the Cassini spacecraft

Elaborate image of Saturn's moon Rhea by the Cassini spacecraft
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Hemispheric color differences on Saturn's moon Rhea are apparent in this false-color view from NASA's Cassini spacecraft. This image shows the side of the moon that always faces the planet.
In this image, the left half of the visible disk of Rhea faces in the direction of Rhea's orbital motion around Saturn, while the right side faces the trailing direction. It is not unusual for large icy Saturnian satellites to exhibit hemispheric albedo (reflectivity) and color differences. These differences are likely related to systematic regional changes in surface composition or the sizes and mechanical structure of grains making up the icy soil. Such large-scale variations can arise from numerous processes, such as meteoritic debris preferentially hitting one side of Rhea. The differences can also arise from "magnetic sweeping," a process that happens when ions that are trapped in Saturn's magnetic field drag over and implant themselves in Rhea's icy surface. The slightly reddish false-color hues near Rhea's poles identify subtle composition changes that might be caused by differences in the surface exposure to meteoric debris falling into the moon or implantation of ions. These differences could vary by latitude. They suggest that at least some of the color differences are exogenic, or derived externally.
This view was captured during Cassini's March 2, 2010 flyby of Rhea. To create the false-color view, ultraviolet, green and infrared images were combined into a single picture that isolates and maps regional color differences. This "color map" was then superimposed over a clear-filter image that preserves the relative brightness across the body.
This view looks toward the Saturn-facing side of Rhea (1528 kilometers, 949 miles across). North is up. The images were taken with the Cassini spacecraft wide-angle camera. The view was acquired at a distance of approximately 35,000 kilometers (22,000 miles) from Rhea and at a sun-Rhea-spacecraft, or phase, angle of 3 degrees. Image scale is 2 kilometers (1 mile) per pixel.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate in Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colorado.
Credit: NASA/JPL/SSI

Sunday, December 19, 2010

A rare picture of Saturn in natural colours, taken by Hubble

A rare picture of Saturn in natural colours, taken by Hubble
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The NASA/ESA Hubble Space Telescope has provided images of Saturn in many colors, from black-and-white, to orange, to blue, green, and red. But in this picture, image processing specialists have worked to provide a crisp, extremely accurate view of Saturn, which highlights the planet's pastel colors. Bands of subtle colour - yellows, browns, grays - distinguish differences in the clouds over Saturn, the second largest planet in the solar system.
The ring swirling around Saturn consists of chunks of ice and dust. Saturn itself is made of ammonia ice and methane gas. The little dark spot on Saturn is the shadow from Saturn's moon Enceladus.
Credit: Hubble Heritage Team (AURA/STScI/NASA/ESA)

Sunday, December 5, 2010

A stunning image of Enceladus by NASA's Cassini spacecraft

A stunning image of Enceladus by NASA's Cassini spacecraft
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Just after coming within 25 kilometers (15.6 miles) of the surface of Enceladus, NASA's Cassini captured this stunning mosaic as the spacecraft sped away from this geologically active moon of Saturn.
Craters and cratered terrains are rare in this view of the southern region of the moon's Saturn-facing hemisphere. Instead, the surface is replete with fractures, folds, and ridges--all hallmarks of remarkable tectonic activity for a relatively small world. In this enhanced-color view, regions that appear blue-green are thought to be coated with larger grains than those that appear white or gray.
Portions of the tiger stripe fractures, or sulci, are visible along the terminator at lower right, surrounded by a circumpolar belt of mountains. The icy moon's famed jets emanate from at least eight distinct source regions, which lie on or near the tiger stripes. However, in this view, the most prominent feature is Labtayt Sulci, the approximately one-kilometer (0.6 miles) deep northward-trending chasm located just above the center of the mosaic.
Near the top, the conspicuous ridges are Ebony and Cufa Dorsae. This false-color mosaic was created from 28 images obtained at seven footprints, or pointing positions, by Cassini's narrow-angle camera. At each footprint, four images using filters sensitive to ultraviolet, visible and infrared light (spanning wavelengths from 338 to 930 nanometers) were combined to create the individual frames. The mosaic is an orthographic projection centered at 64.49 degrees south latitude, 283.87 west longitude, and it has an image scale of 196 kilometers (122.5 miles) per pixel. The original images ranged in resolution from 180 meters (594 feet) to 288 meters (950 feet) per pixel and were acquired at distances ranging from 30,000 to 48,000 kilometers (18,750 to 30,000 miles) as the spacecraft receded from Enceladus. The view was acquired at a Sun-Enceladus-spacecraft, or phase, angle of 73 degrees.
Credit: NASA/JPL/Space Science Institute

The first color view of Titan's surface taken by the Huygens probe

The first color view of Titan's surface taken by the Huygens probe
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This image was captured by the European Space Agency's Huygens probe during its successful descent to land on Titan. This is the colored view, following processing to add reflection spectra data, and gives a better indication of the actual color of the surface.
Initially thought to be rocks or ice blocks, they are more pebble-sized. The two rock-like objects just below the middle of the image are about 15 centimeters (about 6 inches) (left) and 4 centimeters (about 1.5 inches) (center) across respectively, at a distance of about 85 centimeters (about 33 inches) from Huygens. The surface is darker than originally expected, consisting of a mixture of water and hydrocarbon ice. There is also evidence of erosion at the base of these objects, indicating possible fluvial activity.
The image was taken with the Descent Imager/Spectral Radiometer, one of two NASA instruments on the probe.
Credit: NASA/JPL/ESA/University of Arizona