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Dr. Edward C. Stone
Dr. Stone was appointed Dire
…
| Description |
Dr. Stone was appointed Director of the Jet Propulsion Laboratory on January 1, 1991. In this capacity he also serves as a Vice President of Caltech. Dr. Stone earned his associate of arts degree in 1956 from Burlington Junior College before continuing his studies at the University of Chicago. After receiving his master of science (1959) and Ph.D. (1964) degrees in physics, he joined Caltech as a research fellow in physics. Stone was subsequently appointed senior research fellow and assistant professor (1967), associate professor (1971), professor of physics (1976), chairman of Caltech's Division of Physics, Mathematics and Astronomy (1983 - 1988), and Vice President for Astronomical Facilities (1988 - 1990). Since his first cosmic-ray experiments on Discoverer satellites in 1961, Stone has been a principal investigator on nine NASA spacecraft missions and a co- investigator on five other NASA missions for which he developed high resolution instruments for measuring the isotopic and elemental composition of energetic cosmic-ray nuclei. Using these instruments, Stone and his colleagues undertook some of the first studies of the isotopic composition of three distinct samples of matter. The matter arrives at Earth as cosmic rays from nearby regions in our galaxy, as solar energetic particles from the Sun, and as the anomalous component from the local interstellar medium. These instruments also have been used for studies of planetary magnetospheres, including the discovery of energetic sulfur and oxygen ions from Jupiter's satellite, Io. Stone also jointly developed a large-area electronic satellite instrument for measuring the abundance of very rare heavy galactic cosmic-ray nuclei, such as lead and platinum, and collaborated in the development of an imaging gamma-ray telescope. Since 1972, Dr. Stone has served as the project scientist for the Voyager Mission, participating in both hardware development and mission operations. Following launch in 1977 of the twin Voyager spacecraft, he coordinated the efforts of 11 teams of scientists in their studies of Jupiter, Saturn, Uranus and Neptune. Among his many scientific awards and honors, Stone was a Sloan Foundation fellow and has received the NASA Exceptional Scientific Achievement Medal, the NASA Distinguished Service Medal, the American Institute of Aeronautics and Astronautics Dryden Medal and Space Science Award, and the NASA Distinguished Public Service Medal. He is the recipient of the NASA Outstanding Leadership Medal, the Aviation Week and Space Technology Aerospace Laurels Award, the National Space Club Science Award, the Association for Unmanned Vehicle Systems National Award for Operations, the National Medal of Science, the American Philosophical Society Magellanic Award, the American Academy of Achievement Golden Plate Award and the COSPAR Award for Outstanding Contribution to Space Science. He has received honorary degrees from Washington University, St. Louis, Harvard University, and the University of Chicago. Stone is a member of the National Academy of Sciences and the International Academy of Astronautics. He is a fellow of the American Physical Society, the American Geophysical Union, and the American Institute of Aeronautics and Astronautics. He is also a member of the American Astronomical Society, the International Astronomical Union and an honorary member of the Astronomical Society of the Pacific. ##### |
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S-1 C & BW -62
Voyager 1 looked back at Sat
…
12/4/80
| Date |
12/4/80 |
| Description |
Voyager 1 looked back at Saturn on Nov. 16, 1980, four days after the spacecraft flew past the planet, to observe the appearance of Saturn and its rings from this unique perspective. A few of the spokelike ring features discovered by Voyager appear in the rings as bright patches in this image, taken at a distance of 5.3 million kilometers (3.3 million miles) from the planet. Saturn's shadow falls upon the rings, and the bright Saturn crescent is seen through all but the densest portion of the rings. From Saturn, Voyager 1 is on a trajectory taking the spacecraft out of the ecliptic plane, away from the Sun and eventually out of the solar system (by about 1990). Although its mission to Jupiter and Saturn is nearly over (the Saturn encounter ends Dec. 18, 1980), Voyager 1 will be tracked by the Deep Space Network as far as possible in an effort to determine where the influence of the Sun ends and interstellar space begins. Voyager 1's flight path through interstellar space is in the direction of the constellation Ophiuchus. Voyager 2 will reach Saturn on August 25, 1981, and is targeted to encounter Uranus in 1986 and possibly Neptune in 1989. The Voyager project is managed for NASA by the Jet Propulsion Laboratory, Pasadena, California. ##### |
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Dr. Edward C. Stone
Dr. Stone was appointed Dire
…
| Description |
Dr. Stone was appointed Director of the Jet Propulsion Laboratory on January 1, 1991. In this capacity he also serves as a Vice President of Caltech. Dr. Stone earned his associate of arts degree in 1956 from Burlington Junior College before continuing his studies at the University of Chicago. After receiving his master of science (1959) and Ph.D. (1964) degrees in physics, he joined Caltech as a research fellow in physics. Stone was subsequently appointed senior research fellow and assistant professor (1967), associate professor (1971), professor of physics (1976), chairman of Caltech's Division of Physics, Mathematics and Astronomy (1983 - 1988), and Vice President for Astronomical Facilities (1988 - 1990). Since his first cosmic-ray experiments on Discoverer satellites in 1961, Stone has been a principal investigator on nine NASA spacecraft missions and a co- investigator on five other NASA missions for which he developed high resolution instruments for measuring the isotopic and elemental composition of energetic cosmic-ray nuclei. Using these instruments, Stone and his colleagues undertook some of the first studies of the isotopic composition of three distinct samples of matter. The matter arrives at Earth as cosmic rays from nearby regions in our galaxy, as solar energetic particles from the Sun, and as the anomalous component from the local interstellar medium. These instruments also have been used for studies of planetary magnetospheres, including the discovery of energetic sulfur and oxygen ions from Jupiter's satellite, Io. Stone also jointly developed a large-area electronic satellite instrument for measuring the abundance of very rare heavy galactic cosmic-ray nuclei, such as lead and platinum, and collaborated in the development of an imaging gamma-ray telescope. Since 1972, Dr. Stone has served as the project scientist for the Voyager Mission, participating in both hardware development and mission operations. Following launch in 1977 of the twin Voyager spacecraft, he coordinated the efforts of 11 teams of scientists in their studies of Jupiter, Saturn, Uranus and Neptune. Among his many scientific awards and honors, Stone was a Sloan Foundation fellow and has received the NASA Exceptional Scientific Achievement Medal, the NASA Distinguished Service Medal, the American Institute of Aeronautics and Astronautics Dryden Medal and Space Science Award, and the NASA Distinguished Public Service Medal. He is the recipient of the NASA Outstanding Leadership Medal, the Aviation Week and Space Technology Aerospace Laurels Award, the National Space Club Science Award, the Association for Unmanned Vehicle Systems National Award for Operations, the National Medal of Science, the American Philosophical Society Magellanic Award, the American Academy of Achievement Golden Plate Award and the COSPAR Award for Outstanding Contribution to Space Science. He has received honorary degrees from Washington University, St. Louis, Harvard University, and the University of Chicago. Stone is a member of the National Academy of Sciences and the International Academy of Astronautics. He is a fellow of the American Physical Society, the American Geophysical Union, and the American Institute of Aeronautics and Astronautics. He is also a member of the American Astronomical Society, the International Astronomical Union and an honorary member of the Astronomical Society of the Pacific. ##### |
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Old and New Again
| Description |
Old and New Again |
| Full Description |
Miranda, an icy moon of Uranus (see PIA 00141). Miranda is 470-kilometers-wide (290 miles), nearly as large as Enceladus (504 kilometers, or 313 miles wide). The similarities in size and tectonic history on these objects may suggest that remarkably similar physical processes have controlled the separate geological evolutions of these bodies. The images that comprise this mosaic were obtained during Cassini's closest approach to Enceladus on March 9, 2005. The images was taken in visible green light with the Cassini spacecraft narrow-angle camera at a distance of approximately 29,000 kilometers (18,000 miles) from Enceladus and at a Sun-Enceladus-spacecraft, or phase, angle of 46 degrees. Resolution in the original images is about 170 meters (560 feet) 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, Washington, D.C. 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, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . For additional images visit the Cassini imaging team homepage http://ciclops.org . *Credit:* NASA/JPL/Space Science Institute, This false-color Cassini mosaic of Saturn's moon Enceladus captures in a single view, much of the frigid moon's diverse geology. Cratered terrain dominates most of the scene. The relatively dense accumulation of impact craters implies that this terrain is among the oldest on the moon's surface. Near the bottom of the picture is a crater 20 kilometers wide (12-mile) with a prominent dome-shaped structure in its center. The entire area is transected by a complex web of fractures and faults, some are as narrow as a few hundred meters, others as wide as 5 kilometers (3 miles). The rims and interiors of many craters seem to be sliced by a pervasive system of narrow, parallel grooves into slabs or lanes that typically are a kilometer (about a half-mile) in width. The widely varied appearances of fractures in this region attest to the fact that the surface of Enceladus has been shaped by a long history of intense tectonic activity. The oldest fractures are characterized by a soft, muted appearance and are overprinted by numerous, superimposed impact craters. More recent fractures exhibit topographic relief that is relatively "crisp" in appearance, and they appear to slice through pre-existing impact craters and older fractures. On the right side of the image is a conspicuous and twisted network of ridges and troughs forming a distinct tectonic region on Enceladus. The paucity of craters and the sharp appearance of the topography in this area indicate that this is a relatively young terrain on Enceladus. This view is a composite of images taken using filters sensitive to ultraviolet (centered at 338 nanometers), green (centered at 568 nanometers), and near-infrared (centered at 930 nanometers) light, and has been processed to accentuate subtle color differences. The uppermost surface of these terrains has a relatively uniform grayish color in this picture, suggesting that it is covered with materials of homogeneous composition and grain size. However, many of the fractures reveal a distinctly different color (represented by pale-bluish tones in this false-color image) than the typical surface materials. These "colored" fractures seem to penetrate down to a material that is texturally or compositionally different than most of the material at the surface. One possibility is that the walls of the fractures expose outcrops of solid ice, or ice with different grain-sizes compared to powdery surface materials that blanket flat-lying surfaces. It is also possible that the color identifies some compositional difference between buried ice and ice at the surface. The distinct coloration of "youthful" fracture walls are nearly absent in the oldest fractures. This is consistent with the possibility that the older fractures are covered with a drape of particulate material which mantles nearly all the oldest features on the satellite. In the early 1980's, NASA's Voyager mission to the outer planets revealed a strikingly similar arrangement of terrains on |
| Date |
March 16, 2005 |
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| Description |
Here on the Gallery page you can find the very latest images, videos and products from the Cassini-Huygens mission to Saturn, including the spectacular launch, spacecraft assembly and the exciting trip to Saturn. |
| Full Description |
This 1981 Voyager 2 image shows the vast Saturn ring system, as well as three small icy satellites and the shadow of a fourth. Saturn is the second largest planet in the Solar System. It has a volume about 760 times that of Earth. Like Jupiter, Uranus, and Neptune, it has no solid surface, but is instead an enormous sphere of gas which gradually compresses into fluid at great depths beneath the clouds. Most of the visible markings are formed in a layer of ammonia ice clouds, which form at a pressure level in Saturn's atmosphere that is comparable to sea-level atmospheric pressure on Earth. Above those clouds, Saturn's atmosphere, like those of the Sun and the other three gas giant planets, is composed almost exclusively of hydrogen and helium. By contrast, Saturn's rings and icy satellites appear to be composed primarily of water ice. Image reprocessed by USGS. (P-43538) |
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Voyager 2 Launch
| title |
Voyager 2 Launch |
| date |
08.20.1977 |
| description |
Voyager 2 was launched August 20, 1977, sixteen days before Voyager 1 aboard a Titan-Centaur rocket. Their different flight trajectories caused Voyager 2 to arrive at Jupiter four months later than Voyager 1, thus explaining their numbering. The initial mission plan for Voyager 2 specified visits only to Jupiter and Saturn. The plan was augmented in 1981 to include a visit to Uranus, and again in 1985 to include a flyby of Neptune. After completing the tour of the outer planets in 1989, the Voyager spacecraft began exploring interstellar space. The Voyager mission has been managed by NASA's Office of Space Science and the Jet Propulsion Laboratory. *Image Credit*: NASA |
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Solar System Family Portrait
| title |
Solar System Family Portrait |
| description |
These six narrow-angle color images were made from the first ever 'portrait' of the solar system taken by Voyager 1, which was more than 4 billion miles from Earth and about 32 degrees above the ecliptic. The spacecraft acquired a total of 60 frames for a mosaic of the solar system which shows six of the planets. Mercury is too close to the sun to be seen. Mars was not detectable by the Voyager cameras due to scattered sunlight in the optics, and Pluto was not included in the mosaic because of its small size and distance from the sun. These blown-up images, left to right and top to bottom are Venus, Earth, Jupiter, and Saturn, Uranus, Neptune. The background features in the images are artifacts resulting from the magnification. The images were taken through three color filters -- violet, blue and green -- and recombined to produce the color images. Jupiter and Saturn were resolved by the camera but Uranus and Neptune appear larger than they really are because of image smear due to spacecraft motion during the long (15 second) exposure times. Earth appears to be in a band of light because it coincidentally lies right in the center of the scattered light rays resulting from taking the image so close to the sun. Earth was a crescent only 0.12 pixels in size. Venus was 0.11 pixel in diameter. The planetary images were taken with the narrow-angle camera (1500 mm focal length). *Image Note*: This 'Portrait' contains 18 frames taken through the Narrow Angle camera using the Violet, Blue, and Green Filters. The label information describes only 3 of these frames. *Image Credit*: NASA |
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Charon Discovery Image
| title |
Charon Discovery Image |
| date |
06.22.1978 |
| description |
On 22 June 1978, an astronomer at the U.S. Naval Observatory in Washington, D.C. was making routine measurements of photographic plates taken with the 1.55-meter (61-inch) Kaj Strand Astrometric Reflector at the USNO Flagstaff Station in Arizona. The purpose of these images was to refine the orbit of the far-flung planet Pluto to help compute a better ephemeris for this distant object. Astronomer James W. Christy had noticed that a number of the images of Pluto appeared elongated, but images of background stars on the same plate did not. Other plates showed the planet as a tiny, round dot. Christy examined a number of Pluto images from the USNO archives, and he noticed the elongations again. Furthermore, the elongations appeared to change position with respect to the stars over time. After eliminating the possibility that the elongations were produced by plate defects and background stars, the only plausible explanation was that they were caused by a previously unknown moon orbiting Pluto at a distance of about 19,600 kilometers (12,100 miles) with a period of just over six days. On 7 July 1978, the discovery was formally announced to the astronomical community and the world by the IAU Central Bureau for Astronomical Telegrams via IAU Circular 3241. The discovery received the provisional designation "1978 P 1", Christy proposed the name "Charon", after the mythological ferryman who carried souls across the river Acheron, one of the five mythical rivers that surrounded Pluto's underworld. Over the course of the next several years, another USNO astronomer, the late Robert S. Harrington, calculated that Pluto and its newly-found moon would undergo a series of mutual eclipses and occultations, beginning in early 1985. On 17 February 1985 the first successful observation of one of these transits was made at with the 0.9-meter (36-inch) reflector at the University of Texas McDonald Observatory, within 40 minutes of Harrington's predicted time. The IAU Circular announcing these confirming observations was issued on 22 February 1985. With this confirmation, the new moon was officially named Charon. Pluto was discovered at Lowell Observatory in 1930 by the late Clyde W. Tombaugh, an amateur astronomer from Kansas who was hired by the Observatory specifically to photograph the sky with a special camera and search for the planet predicted by the Observatory's founder, Percival Lowell. Lowell had deduced the existence of a "Planet X" by studying small anomalies in the orbits of Uranus and Neptune. As it turned out, Pluto's discovery was almost entirely serendipitous, Pluto's tiny mass was far too small to account for the anomalies, which were resolved when Voyager 2 determined more precise masses for Uranus and Neptune. The discovery of Charon has led to a much better understanding of just how tiny Pluto is. Its diameter is about 2274 km (1413 miles), and its mass is 0.25% of the mass of the Earth. Charon has a diameter of about 1172 kilometers (728, miles) and a mass of about 22% that of Pluto. The two worlds circle their common center of mass with a period of 6.387 days and are locked in a "super-synchronous" rotation: observers on Pluto's surface would always see Charon in the same part of the sky relative to their local horizon. Normally Pluto is considered the most distant world in the solar system, but during the period from January 1979 until February 1999 it was actually closer to the Sun than Neptune. It has the most eccentric and inclinced orbit of any of the major planets. This orbit won't bring Pluto back to its discovery position until the year 2178! *Image Credit*: U.S. Naval Observatory |
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Uranus' innermost satellite
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| title |
Uranus' innermost satellite Miranda |
| date |
01.24.1986 |
| description |
Miranda, innermost of Uranus' large satellites, is seen at close range in this Voyager 2 image, taken Jan. 24, 1986, as part of a high-resolution mosaicing sequence. Voyager was some 36,000 kilometers (22,000 miles) away from Miranda. This clear-filter, narrow-angle image shows an area about 250 km (150 mi) across, at a resolution of about 800 meters (2,600 feet). Two distinct terrain types are visible: a rugged, higher-elevation terrain (right) and a lower, striated terrain. Numerous craters on the rugged, higher terrain indicate that it is older than the lower terrain. Several scarps, probably faults, cut the different terrains. The impact crater in the lower part of this image is about 25 km (15 mi) across. The Voyager project is managed for NASA by the Jet Propulsion Laboratory. *Image Credit*: NASA |
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Uranus
| title |
Uranus |
| description |
This is a view of Uranus taken by Voyager 2. This image was taken through three color filters and recombined to produce the color image. JPL manages and controls the Voyager project for NASA's Office of Space Science. *Image Credit*: NASA |
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Uranus Ring System
| title |
Uranus Ring System |
| description |
This dramatic Voyager 2 picture reveals a continuous distribution of small particles throughout the Uranus ring system. Voyager took this image while in the shadow of Uranus, at a distance of 236,000 kilometers (142,000 miles and a resolution of about 33 km (20 ml). This unique geometry -- the highest phase angle at which Voyager imaged the rings -- allows us to see lanes of fine dust particles not visible from other viewing angles. All the previously known rings are visible here, however, some of the brightest features in the image are bright dust lanes not previously seen. The combination of this unique geometry and a long, 96 second exposure allowed this spectacular observation, acquired through the clear filter of Voyager's wide-angle camera. The long exposure produced a noticeable, non-uniform smear as well as streaks due to trailed stars. The Voyager project is managed for NASA by the Jet Propulsion Laboratory. *Image Credit*: JPL |
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Hubble Captures Detailed Ima
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| title |
Hubble Captures Detailed Image of Uranus' Atmosphere |
| date |
07.03.1995 |
| description |
Hubble Space Telescope has peered deep into Uranus' atmosphere to see clear and hazy layers created by a mixture of gases. Using infrared filters, Hubble captured detailed features of three layers of Uranus' atmosphere. Hubble's images are different from the ones taken by the Voyager 2 spacecraft, which flew by Uranus 10 years ago. Those images - not taken in infrared light - showed a greenish-blue disk with very little detail. The infrared image allows astronomers to probe the structure of Uranus' atmosphere, which consists of mostly hydrogen with traces of methane. The red around the planet's edge represents a very thin haze at a high altitude. The haze is so thin that it can only be seen by looking at the edges of the disk, and is similar to looking at the edge of a soap bubble. The yellow near the bottom of Uranus is another hazy layer. The deepest layer, the blue near the top of Uranus, shows a clearer atmosphere. Image processing has been used to brighten the rings around Uranus so that astronomers can study their structure. In reality, the rings are as dark as black lava or charcoal. This false color picture was assembled from several exposures taken July 3, 1995 by the Wide Field Planetary Camera-2. The Wide Field/Planetary Camera 2 was developed by the Jet Propulsion Laboratory and managed by the Goddard Spaced Flight Center for NASA's Office of Space Science. This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu *Image Credit*: Erich Karkoschka (University of Arizona Lunar & Planetary Lab) and NASA |
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Hubble Spots Northern Hemisp
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| title |
Hubble Spots Northern Hemispheric Clouds on Uranus |
| date |
07.31.1997 |
| description |
Using visible light, astronomers for the first time this century have detected clouds in the northern hemisphere of Uranus. The newest images, taken July 31 and Aug. 1, 1997 with NASA Hubble Space Telescope's Wide Field and Planetary Camera 2, show banded structure and multiple clouds. Using these images, Dr. Heidi Hammel (Massachusetts Institute of Technology) and colleagues Wes Lockwood (Lowell Observatory) and Kathy Rages (NASA Ames Research Center) plan to measure the wind speeds in the northern hemisphere for the first time. Uranus is sometimes called the "sideways" planet, because its rotation axis tipped more than 90 degrees from the planet's orbit around the Sun. The "year" on Uranus lasts 84 Earth years, which creates extremely long seasons - winter in the northern hemisphere has lasted for nearly 20 years. Uranus has also been called bland and boring, because no clouds have been detectable in ground-based images of the planet. Even to the cameras of the Voyager spacecraft in 1986, Uranus presented a nearly uniform blank disk, and discrete clouds were detectable only in the southern hemisphere. Voyager flew over the planet's cloud tops near the dead of northern winter (when the northern hemisphere was completely shrouded in darkness). Spring has finally come to the northern hemisphere of Uranus. The newest images, both the visible-wavelength ones described here and those taken a few days earlier with the Near Infrared and Multi-Object Spectrometer (NICMOS) by Erich Karkoschka (University of Arizona), show a planet with banded structure and detectable clouds. Two images are shown here. The "aqua" image (on the left) is taken at 5,470 Angstroms, which is near the human eye's peak response to wavelength. Color has been added to the image to show what a person on a spacecraft near Uranus might see. Little structure is evident at this wavelength, though with image-processing techniques, a small cloud can be seen near the planet's northern limb (rightmost edge). The "red" image (on the right) is taken at 6,190 Angstroms, and is sensitive to absorption by methane molecules in the planet's atmosphere. The banded structure of Uranus is evident, and the small cloud near the northern limb is now visible. Scientists are expecting that the discrete clouds and banded structure may become even more pronounced as Uranus continues in its slow pace around the Sun. "Some parts of Uranus haven't seen the Sun in decades," says Dr. Hammel, "and historical records suggest that we may see the development of more banded structure and patchy clouds as the planet's year progresses." Some scientists have speculated that the winds of Uranus are not symmetric around the planet's equator, but no clouds were visible to test those theories. The new data will provide the opportunity to measure the northern winds. Hammel and colleagues expect to have results soon. The Wide Field/Planetary Camera 2 was developed by the Jet Propulsion Laboratory and managed by, the Goddard Spaced Flight Center for NASA's Office of Space Science. This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu *Image Credit*: Heidi Hammel (Massachusetts Institute of Technology), NASA |
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Uranian Moons
| title |
Uranian Moons |
| date |
01.26.1986 |
| description |
This "family portrait" of Uranus' five largest moons was compiled from images sent back Jan. 20, 1986, by the Voyager 2 spacecraft. The pictures were taken through a clear filter from distances of 5.0 million to 6.1 million kilometers (3.1 million to 3.8 million miles). In this comparison, we see the relative sizes and relativities of the satellites. From left, in order of increasing distance from the planet, they are Miranda, Ariel, Umbriel, Titania and Oberon. The two largest, Oberon and Titania, are about half the size of Earth's Moon, or roughly, 1,600 kilometers (1,000 miles) in diameter. Miranda, smallest of the five, has about one-quarter to one-third the diameter. Even in these distant views, the satellites exhibit distinct differences in appearance. On average, Oberon and Titania reflect about 20 percent of the sunlight, Umbriel about 12 percent, Ariel and Miranda about 30 percent. Ariel shows the largest contrast on its surface, with the brightest areas about 25 percent. All five satellites show only slight color variations on their surfaces, with their average color being very nearly gray. The best views of the satellites will be obtained Jan. 24, the day of closest approach. *Image Credit*: NASA |
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Hubble Tracks Clouds on Uran
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| title |
Hubble Tracks Clouds on Uranus |
| date |
07.28.1997 |
| description |
Taking its first peek at Uranus, NASA Hubble Space Telescope's Near Infrared Camera and Multi-Object Spectrometer (NICMOS) has detected six distinct clouds in images taken July 28,1997. The image on the right, taken 90 minutes after the left-hand image, shows the planet's rotation. Each image is a composite of three near-infrared images. They are called false-color images because the human eye cannot detect infrared light. Therefore, colors corresponding to visible light were assigned to the images. (The wavelengths for the "blue,""green," and "red" exposures are 1.1, 1.6, and 1.9 micrometers, respectively.) At visible and near-infrared light, sunlight is reflected from hazes and clouds in the atmosphere of Uranus. However, at near-infrared light, absorption by gases in the Uranian atmosphere limits the view to different altitudes, causing intense contrasts and colors. In these images, the blue exposure probes the deepest atmospheric levels. A blue color indicates clear atmospheric conditions, prevalent at mid-latitudes near the center of the disk. The green exposure is sensitive to absorption by methane gas, indicating a clear atmosphere, but in hazy atmospheric regions, the green color is seen because sunlight is reflected back before it is absorbed. The green color around the south pole (marked by "+") shows a strong local haze. The red exposure reveals absorption by hydrogen, the most abundant gas in the atmosphere of Uranus. Most sunlight shows patches of haze high in the atmosphere. A red color near the limb (edge) of the disk indicates the presence of a high-altitude haze. The purple color to the right of the equator also suggests haze high in the atmosphere with a clear atmosphere below. The five clouds visible near the right limb rotated counterclockwise during the time between both images. They reach high into the atmosphere, as indicated by their red color. Features of such high contrast have never been seen before on Uranus. The clouds are almost as large as continents on Earth, such as Europe. Another cloud (which barely can be seen) rotated along the path shown by the black arrow. It is located at lower altitudes, as indicated by its green color. The rings of Uranus are extremely faint in visible light but quite prominent in the near infrared. The brightest ring, the epsilon ring, has a variable width around its circumference. Its widest and thus brightest part is at the top in this image. Two fainter, inner rings are visible next to the epsilon ring. Eight of the 10 small Uranian satellites, discovered by Voyager 2, can be seen in both images. Their sizes range from about 25 miles (40 kilometers) for Bianca to 100 miles (150 kilometers) for Puck. The smallest of these satellites have not been detected since the departure of Voyager 2 from Uranus in 1986. These eight satellites revolve around Uranus in less than a day. The inner ones are faster than the outer ones. Their motion in the 90 minutes between both images is, marked in the right panel. The area outside the rings was slightly enhanced in brightness to improve the visibility of these faint satellites. The Wide Field/Planetary Camera 2 was developed by the Jet Propulsion Laboratory and managed by the Goddard Spaced Flight Center for NASA's Office of Space Science. This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu/ *Image Credit*: NASA |
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Miranda as seen by Voyager 2
| Title |
Miranda as seen by Voyager 2 |
| Full Description |
Flying by in early 1986, Voyager 2 captured this picture of Miranda, which enabled scientists to study this moon of Uranus in much greater detail than ever before. Discovered in 1948 by Gerard Peter Kuiper, Miranda is named for the daughter of the wily Prospero in Shakespeare's "The Tempest." It is the eleventh known satellite of Uranus and the innermost large moon of Uranus It was necessary that Voyager 2 passed by Miranda, not for scientific reasons, but simply for the gravity assist it needed to go on to Neptune. Due to the position of the entire Solar System, Miranda provided the energy to throw Voyager 2 to Neptune. Before Voyager, Miranda was largely ignored as it is not the largest moon and did not seem to have any other outstanding qualities. Fortunately, however, Voyager passed close enough to Miranda to provide scientists with fascinating photographs that captivated astronomers. About half ice and half rock, Miranda's surface has terraced layers that indicate both older and new surfaces coexisting. Since the mixing of ancient and recent surfaces is rare in planetary geology, scientists have postulated two explanations for the different ages of the numerous valleys and cliffs on Miranda. One theory is that Miranda could have shattered as many as five times and was then reassembled. Another hypothesis is that partly melted ice upwells forced new surfaces to emerge. |
| Date |
01/25/1986 |
| NASA Center |
Jet Propulsion Laboratory |
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Solar System Montage
| Title |
Solar System Montage |
| Full Description |
This is a montage of planetary images taken by spacecraft managed by the Jet Propulsion Laboratory in Pasadena, CA. Included are (from top to bottom) images of Mercury, Venus, Earth (and Moon), Mars, Jupiter, Saturn, Uranus and Neptune. The spacecraft responsible for these images are as follows: the Mercury image was taken by Mariner 10, the Venus image by Magellan, the Earth image by Galileo, the Mars image by Viking, and the Jupiter, Saturn, Uranus and Neptune images by Voyager. Pluto is not shown as no spacecraft has yet visited it. The inner planets (Mercury, Venus, Earth, Moon, and Mars) are roughly to scale to each other, the outer planets (Jupiter, Saturn, Uranus, and Neptune) are roughly to scale to each other. Actual diameters are given below: Sun 1,390,000 km Mercury 4,879 km Venus 12,104 km Earth 12,756 km Moon 3,475 km Mars 6,794 km Jupiter 142.984 km Saturn 120,536 km Uranus 51,118 km Neptune 49,528 km Pluto 2,390 km |
| Date |
04/09/1999 |
| NASA Center |
Jet Propulsion Laboratory |
|
Solar System Montage of Voya
…
| Title |
Solar System Montage of Voyager Images |
| Full Description |
This montage of images taken by the Voyager spacecraft of the planets and four of Jupiter's moons is set against a false-color Rosette Nebula with Earth's moon in the foreground. Studying and mapping Jupiter, Saturn, Uranus, Neptune, and many of their moons, Voyager provided scientists with better images and data than they had ever had before or expected from the program. Although launched sixteen days after Voyager 2, Voyager 1's trajectory was a faster path, arriving at Jupiter in March 1979. Voyager 2 arrived about four months later in July 1979. Both spacecraft were then directed to Saturn with Voyager 1 arriving in November 1980 and Voyager 2 in August 1981. Voyager 2 was then diverted to the remaining gas giants, Uranus in January 1986 and Neptune in August 1989. Data collection continues by both Voyager 1 and 2 as the renamed Voyager Interstellar Mission searches for the edge of the solar wind influence (the heliopause) and exits the Solar System. A shortened list of the discoveries of Voyager 1 and 2 include:the discovery of the Uranian and Neptunian magnetospheres (magnetic environments caused by various types of planet cores), the discovery of twenty-two new satellites including three at Jupiter, three at Saturn, ten at Uranus, and six at Neptune, Io was found to have active volcanism (the only other Solar System body than Earth to be confirmed), Triton was found to have active geyser-like structures and an atmosphere, Auroral Zones (where gases become excited after being hit by solar particles) were discovered at Jupiter, Saturn, and Neptune, Jupiter was found to have rings, Neptune, originally thought to be too cold to support such atmospheric disturbances, had large-scale storms. |
| Date |
UNKNOWN |
| NASA Center |
Jet Propulsion Laboratory |
|
Uranus
| Title |
Uranus |
| Full Description |
This computer enhancement of a Voyager 2 image, emphasizes the high-level haze in Uranus' upper atmosphere. Clouds are obscured by the overlying atmosphere. JPL manages and controls the Voyager project for NASA's Office of Space Science, Washington, DC. |
| Date |
01/01/1986 |
| NASA Center |
Jet Propulsion Laboratory |
|
Voyager 2 Launch
| Title |
Voyager 2 Launch |
| Full Description |
Voyager 2 was launched August 20, 1977, sixteen days before Voyager 1 aboard a Titan-Centaur rocket. Their different flight trajectories caused Voyager 2 to arrive at Jupiter four months later than Voyager 1, thus explaining their numbering. The initial mission plan for Voyager 2 specified visits only to Jupiter and Saturn. The plan was augmented in 1981 to include a visit to Uranus, and again in 1985 to include a flyby of Neptune. After completing the tour of the outer planets in 1989, the Voyager spacecraft began exploring interstellar space. The Voyager mission has been managed by NASA's Office of Space Science and the Jet Propulsion Laboratory. |
| Date |
08/20/1977 |
| NASA Center |
Kennedy Space Center |
|
Voyager Spacecraft During Vi
…
| Title |
Voyager Spacecraft During Vibration Testing |
| Full Description |
Two Voyager spacecraft were launched in 1977 to explore the outer planets and some of their satellites. A prototype Voyager spacecraft is shown at NASA's Jet Propulsion Laboratory in Pasadena, California, as it successfully passed vibration tests which simulated the expected launch environment. The large parabolic antenna at the top is 3.7 meters in diameter and was used at both S-band and X-band radio frequencies for communicating with Earth over the great distances from the outer planets. The spacecraft received electrical power from three nuclear power sources (lower left). The shiny cylinder on the left side under the antenna contained a folded boom, which extended after launch to hold a magnetometer instrument thirteen meters away from the body of the spacecraft. The truss-like structure on the right side is the stowed instrument boom which supported three science instruments and a scan platform. The scan platform allowed the accurate pointing of two cameras and three other science instruments at Jupiter, Saturn, the rings of Saturn, Jupiter's moons, Saturn's moons, Uranus, moons of Uranus, and Neptune. |
| Date |
03/25/1977 |
| NASA Center |
Jet Propulsion Laboratory |
|
Voyager Tour Montage
| Title |
Voyager Tour Montage |
| Full Description |
This montage of images of the planets visited by Voyager 2 was prepared from an assemblage of images taken by the Voyager 2 spacecraft. The Voyager Project is managed for NASA by the Jet Propulsion Laboratory, Pasadena, California. |
| Date |
08/01/1989 |
| NASA Center |
Jet Propulsion Laboratory |
|
Hubble Observes the Moons an
…
| Title |
Hubble Observes the Moons and Rings of the Planet Uranus |
|
Hubble Observes the Moons an
…
| Title |
Hubble Observes the Moons and Rings of the Planet Uranus |
|
Hubble Captures Detailed Ima
…
| Title |
Hubble Captures Detailed Image of Uranus's Atmosphere |
|
Hubble Watches Uranus
| Title |
Hubble Watches Uranus |
|
Hubble Watches Uranus
| Title |
Hubble Watches Uranus |
|
Hubble Uncovers Smallest Moo
…
| Title |
Hubble Uncovers Smallest Moons Yet Seen Around Uranus |
|
Hubble Uncovers Smallest Moo
…
| Title |
Hubble Uncovers Smallest Moons Yet Seen Around Uranus |
|
Hubble Discovers Dark Cloud
…
| Title |
Hubble Discovers Dark Cloud in the Atmosphere of Uranus |
|
Going, Going, Gone: Hubble C
…
| Title |
Going, Going, Gone: Hubble Captures Uranus's Rings on Edge |
|
NASA's Hubble Discovers New
…
| Title |
NASA's Hubble Discovers New Rings and Moons Around Uranus |
|
Hubble Observes the Moons an
…
| Title |
Hubble Observes the Moons and Rings of the Planet Uranus |
|
A77-0851
Photographer: N/A Voyager Sa
…
7/6/77
| Description |
Photographer: N/A Voyager Saturn Mission Artwork (Mariner - Jupiter - Saturn - Uranus) show slingshot technique |
| Date |
7/6/77 |
|
A86-7001
Photographer : JPL Range: 72
…
11/28/85
| Description |
Photographer : JPL Range: 72.3 million km. ( 44.9 million miles ) P-29314B/W This Voyager 2 photograph of Uranus shows the planets outermost, or epsilon, ring. This is a computerized summation of six images shot by the narrow angle camera. It is the first photo to show the epsilon ring unblurred by Earth's atmosphere. The Epsilon ring, some 51,200 km. ( 31,800 miles ) from the planets center, is the most prominent of Uranus' nine known rings. Ground based observations of stellar occulations by the rings have determined that the Epsilon ring is eccentric, or elliptical, with its widest portion about 100 km. ( 60 miles ) wide and its narrowest portion about 20 km. (12 miles ). Estimates of the rings brightness suggest that it is also very dark, with a reflectance of only 1 or 2 percent and a probable composition of carbonaceous material similiar to that on dark asteroids and the dark side of Saturn's moon Lapetus. Because the ring is so narrow and dark, at this range, the Voyager camera could not resolve even the widest part, resulting in long exposure times so obtain a good image. six exposures of 11 or 15 second duration were added together by computer to produce this image. In this image, the central portion is greatly overexposed. Various artifacts due to electronic effects and image proccessing can be seen in the central portion of the frame, including the dark image just above the planets image, the diffuse brightening below it and the small, bright projection from the edge of the planet in the upper left. The ring is distinctly less prominent in the lower left portion and more prominent in the upper right. This is in agreement with the predicted locations of the narrow and wide portions of the ring, respectively. |
| Date |
11/28/85 |
|
A86-7007
Photographer : JPL Range : 1
…
1/14/81
| Description |
Photographer : JPL Range : 12.9 million km. ( 8.0 million miles ) P-29467B/W Time lapse Voyager 2 images of Uranus show the movement of two small, bright, streaky clouds, the first such features ever seen on the planet. The clouds were detected in this series of orange filtered images, over a 4.6 hour interval ( from top to bottom ). Uranus, which is tipped on its side with respect to the other planets, is rotating in a counter-clockwise direction, with its pole of rotation near the center of the disk, as are the two clouds seen here as bright streaks. The larger of the two clouds is ata lattitude of 33 degrees. The smaller cloud, seen faintly in the three lower images, lies at 26 degrees ( a lower alttitude and hence closer to the limb). Their counterclockwise periods of rotation are 16.2 and 16.9 hours, respectively. This difference implies that the lower lattitude feature is lagging behind the higher latitude feture at a speed of almost 100 meters pers second (220 mph). Latitudinal bands are also visible in these images, the faint bands, more numerous now then in previous Voyager images from longer range, are concentric with the pole rotation. thatis, they circle the planet in lines of contant latitude. |
| Date |
1/14/81 |
|
A86-7011
Photographer : JPL Range : 2
…
1/14/86
| Description |
Photographer : JPL Range : 2.52 million miles (1.56 million miles) P-29481B/W Voyager 2 returned this photograph with all nine known Uranus rings visible from a 15 sec. exposure through the narrow angle camera. The rings are quite dark and very narrow. The most prominent and outermost of the nine, Epsilon, is seen at top. The next three in toward Uranus, called Delta, Gamma, and Eta, are much fainter and more narrow than Epsilon ring. Then come Beta and Alpha rings, and finally, the innermost grouping, known simply as the 4,5, & 6 rings. The last three are very faint and are at the limit of detection for the Voyager camera. Uranus' rings range in width from about 100 km. (60 mi.) at the widest part of the Epsilon ring, to only a few kilometers for most of the others. this iamge was processed to enhance narrow features, the bright dots are imperfections on the camera detector. The resolution scale is about 50 km. (30 mi.) |
| Date |
1/14/86 |
|
A86-7022
Photographer: JPL P-29506BW
…
1/25/86
| Description |
Photographer: JPL P-29506BW Range: 1.12 million kilometers (690,000 miles) This high-resolution image of the epsilon ring of Uranus is a clear-filter picture from Voyager's narrow-angle camera and has a resolution of about 10 km (6 mi). The epsilon ring, approx. 100 km (60 mi) wide at this location, clearly shows a structural variation. Visible here are a broad, bright outer component about 40 km (25 mi) wide, a darker, middle region of comparable width, and a narrow, bright inner strip about 15 km (9 mi) wide. The epsilon-ring structure seen by Voyager is similiar to that observed from the ground with stellar-occultation techniques. This frame represents the first Voyager image that resolves these features within the epsilon ring. The occasional fuzzy splotches on the outer and innerparts of the ring are artifacts left by the removal of reseau marks (used for making measurements on the image). |
| Date |
1/25/86 |
|
A86-7035
Photographer: JPL P-29519BW
…
1/27/86
| Description |
Photographer: JPL P-29519BW Range: 500,000 kilometers (300,000 miles) Several craters are seen on the surface of 1986U1, one of the several small moons of Uranus discovered by Voyager 2. This single image, a clear-filtered, narrow-angle picture with a resolution of about 10 km (6 mi), is the only closeup the spacecraft obtained of any of the new moons. The moon was found December 30, 1985, it was the first and largest of nine satellites discovered by the spacecraft's cameras. This image shows 1986U1 to be a dark, nearly spherical object, with a diameter of about 150 km (90 mi), the dark surface reflects only 7 percent of the incident light. The picture was inserted into the Voyager encounter sequence late in its development.This image has had a complex history, having been recorded on the spacecraft tape recorder and first played back during the late afternoon of its recording. An antenna-pointing problem at one of the Austrailian tracking stations led to the loss of the data, so the image had to be retransmitted. |
| Date |
1/27/86 |
|
A86-7036
Photographer: JPL P-29520 BW
…
1/27/86
| Description |
Photographer: JPL P-29520 BW Range: 130,000 kilometers (80,000 miles) This mosaic, taken through the clear-filter, narrow-angle camera, of the four highest-resolution images of Ariel represents the most detailed Voyager 2 picture of this satellite of Uranus. Ariel is about 1,200 km (750 mi) in diameter, the resolution here is 2.4 km (1.5 mi). Much of Ariel's surface is densely pitted with craters 5 to 10 km (3 to 6 mi) across. These craters are close to the threshold of detection in this picture. Numerous valleys and fault scarps crisscross the highly pitted terrain. voyager scientists believe the valleys have formed over down-dropped fault blocks (graben), apparently, extensive faulting has occured as a result of expansion and stretching of Ariel's crust. The largest fault valleys, near the terminator at right, as well as a smooth region near the center of this image, have been partly filled with deposits that are younger and less heavily cratered than the pitted terrain. Narrow, somewhat sinuous scarps and valleys have been formed, in turn, in these young deposits. It is not yet clear whether these sinuous features have been formed by faulting or by the flow of fluids. |
| Date |
1/27/86 |
|
A89-7039
Photographer: JPL P-34712 Ra
…
8/26/89
| Description |
Photographer: JPL P-34712 Range: 1.1 million kilometers (683,000 miles) This wide-angle Voyager 2 image, taken through the camera's clear filter, is the first to show Neptune's rings in detail. The two main rings, about 53,000 km (33,000 miles) and 63,000 km (39,000 miles) from Neptune, are 5 to 10 times brighter than in earlier images. The difference is due to lighting and viewing geometry. In approach images, the rings were seen in light scattered backward toward the spacecraft at a 15 _ phase angle. However, this image was taken at a 135 _ phase angle as Voyager left the planet. That geometry is ideal for detecting microscopic particles that forward scatter light preferentially. The fact that Neptune's rings are so much brighter at that angle means the particle-size distribution is quite different from most of Uranus' and Saturn's rings, which contain fewer dust-size grains. However, a few componenets of the Saturian and Uranian ring systems exhibit forward-scattering behavior: The F ring and the Encke Gap ringlet at Saturn and 1986U1R at Uranus. They are also narrow, clumpy ringlets with kinks, and are associated with nearby moonlets too small to detect directly. In this image, the main clumpy arc, composed of three features each about 6 to 8 degrees long, is clearly seen. Exposure time for this image was 111 seconds. |
| Date |
8/26/89 |
|
AC86-7008
Photographer : JPL Range : 1
…
1/14/86
| Description |
Photographer : JPL Range : 12.9 million miles (8.0 million miles) P-29468C This false color Voyager photograph of Uranus shows a discrete cloud seen as a bright streak near the planets limb. The cloud visible here is the most prominent feature seen in a series of Voyager images designed to track atmospheric motions. The occasional donut shaped features, including one at the bottom, are shadows cast by dust on the camera optics. The picture is a highly processed composite of three images. The processing necessary to bring out the faint features on the planet also brings out these camera blemishes. The three seperate images used where shot through violet, blue, and orange filters. Each color image showd the cloud to a different degree, because they were not exposed at the same time , the images were processed to provide a good spatial match. In a true color image, the cloud would be barely discernable, the false color helps to bring out additional details. The different colors imply variations in vertical structure, but as of yet it is not possible to be specific about such differences. One possiblity is that the uranian atmosphere may contain smog like constituents, in which case some color differences may represent differences in how these molecules are distributed. |
| Date |
1/14/86 |
|
AC86-7014
Photographer : JPL Range : 2
…
1/22/86
| Description |
Photographer : JPL Range : 2.7 million miles (1.7 million miles) P-29497C Tis Voyager 2, false color composite of Uranus demonstrates the usefulness of special filters in the Voyager cameras for revealing the presence of high altitude hazes in Uranus' atmosphere. The picture is a composite of images obtained through the single orange and two methane filters of Voyager's wide angle camera. Orange, short wavelength and long wavelength methane images are displayed, retrospectively, as blue, green, and orange. The pink area centered on the pole is due to the presence of hazes high in the atmosphere that reflect the light before it has traversed a long enough path through the atmosphere to suffer absorbtion by methane gas. The bluest region at mid-latitude represent the most haze free regions on Uranus, thus, deeper cloud levels can be detected in these areas. |
| Date |
1/22/86 |
|
AC86-7018
Photographer: JPL P-29502C R
…
1/25/86
| Description |
Photographer: JPL P-29502C Range: 1.04 million kilometers (650,000 miles) This color photo of Umbriel, the darkest of Uranus' five large moons was synthesized from frames exposed with the Voyager narrow-angle camera's violet and clear filters and has a resolution of 19 km (12 mi.). Umbriel is characterized by the darkest surface and smallest brightness variations of any of the large satellites of Uranus. As seen here, the surface is also generally gray and colorless. Nevertheless, at this resolution, considerable topographic detail is revealed, showing that Umbriel's surface is covered by impact craters. The brightest spot (shown at top near the equator at approxiamately 270 _ longitude) appears as a bright ring. Its geological significance is not yet understood. Umbriel has a diameter of about 1,200 km (750 miles) and orbits 267,000 km (166,000 mi) from Uranus' center. The satellite's name, from Alexander Pope's "Rape of the Lock," means "dark angel". |
| Date |
1/25/86 |
|
Jupiter, its great Red Spot
…
| Name of Image |
Jupiter, its great Red Spot three of its four largest satellites |
| Date of Image |
1979-02-05 |
| Full Description |
On February 5, 1979, Voyager 1 made its closest approach to Jupiter since early 1974 and 1975 when Pioneers 10 and 11 made their voyages to Jupiter and beyond. Voyager 1 completed its Jupiter encounter in early April, after taking almost 19,000 pictures and recording many other scientific measurements. Although astronomers had studied Jupiter from Earth for several centuries, scientists were surprised by many of Voyager 1 and 2's findings. They now understand that important physical, geological, and atmospheric processes go on that they had never observed from Earth. Discovery of active volcanism on the satellite Io was probably the greatest surprise. It was the first time active volcanoes had been seen on another body in the solar system. Voyager also discovered a ring around Jupiter. Thus Jupiter joins Saturn, Uranus, and Neptune as a ringed planet -- although each ring system is unique and distinct from the others. |
|
Ariel at Voyager Closest App
…
| Title |
Ariel at Voyager Closest Approach |
| Description |
This picture is part of the highest-resolution Voyager 2 imaging sequence of Ariel, a moon of Uranus about 1,300 kilometers (800 miles) in diameter. The clear-filter, narrow-angle image was taken Jan. 24, 1986, from a distance of 130,000 km (80,000 mi). The complexity of Ariel's surface indicates that a variety of geologic processes have occurred. The numerous craters, for example, are indications of an old surface bombarded by meteoroids over a long period. Also conspicuous at this resolution, about 2.4 km (1.5 mi), are linear grooves (evidence of tectonic activity that has broken up the surface) and smooth patches (indicative of deposition of material). The Voyager project is managed for NASA by the Jet Propulsion Laboratory. |
| Date |
01.26.1986 |
|
Ariel's Densely Pitted Surfa
…
| Title |
Ariel's Densely Pitted Surface |
| Description |
This mosaic of the four highest-resolution images of Ariel represents the most detailed Voyager 2 picture of this satellite of Uranus. The images were taken through the clear filter of Voyager's narrow-angle camera on Jan. 24, 1986, at a distance of about 130,000 kilometers (80,000 miles). Ariel is about 1,200 km (750 mi) in diameter, the resolution here is 2.4 km (1.5 mi). Much of Ariel's surface is densely pitted with craters 5 to 10 km (3 to 6 mi) across. These craters are close to the threshold of detection in this picture. Numerous valleys and fault scarps crisscross the highly pitted terrain. Voyager scientists believe the valleys have formed over down-dropped fault blocks (graben), apparently, extensive faulting has occurred as a result of expansion and stretching of Ariel's crust. The largest fault valleys, near the terminator at right, as well as a smooth region near the center of this image, have been partly filled with deposits that are younger and less heavily cratered than the pitted terrain. Narrow, somewhat sinuous scarps and valleys have been formed, in turn, in these young deposits. It is not yet clear whether these sinuous features have been formed by faulting or by the flow of fluids. JPL manages the Voyager project for NASA's Office of Space Science. |
| Date |
01.27.1986 |
|
Neptune's rings
| Title |
Neptune's rings |
| Description |
This wide-angle Voyager 2 image, taken through the camera's clear filter, is the first to show Neptune's rings in detail. The two main rings, about 53,000 km (33,000 miles) and 63,000 km (39,000 miles) from Neptune, are 5 to 10 times brighter than in earlier images. The difference is due to lighting and viewing geometry. In approach images, the rings were seen in light scattered backward toward the spacecraft at a 15-degree phase angle. However, this image was taken at a 135-degree phase angle as Voyager left the planet. That geometry is ideal for detecting microscopic particles that forward-scatter light preferentially. The fact that Neptune's rings are so much brighter at that angle means the particle-size distribution is quite different from most of Uranus' and Saturn's rings, which contain fewer dust-size grains. However, a few components of the Saturnian and Uranian ring systems exhibit forward-scattering behavior: The F ring and the Encke Gap ringlet at Saturn, and 1986U1R at Uranus. They are also narrow, clumpy ringlets with kinks, and are associated with nearby moonlets too small to detect directly. In this image, the main clumpy arc, composed of three features each about 6 to 8 degrees long, is clearly seen. This image was obtained when Voyager was 1.1 million km (683,000 miles) from Neptune. Exposure time was 111seconds. The Voyager Mission is conducted by JPL for NASA's Office of Space Science and Applications. |
| Date |
08.26.1989 |
|
Oberon at Voyager Closest Ap
…
| Title |
Oberon at Voyager Closest Approach |
| Description |
This Voyager 2 picture of Oberon is the best the spacecraft acquired of Uranus' outermost moon. The picture was taken shortly after 3:30 a.m. PST on Jan. 24, 1986, from a distance of 660,000 kilometers (410,000 miles). The color was reconstructed from images taken through the narrow-angle camera's violet, clear and green filters. The picture shows features as small as 12 km (7 mi) on the moon's surface. Clearly visible are several large impact craters in Oberon's icy surface surrounded by bright rays similar to those seen on Jupiter's moon Callisto. Quite prominent near the center of Oberon's disk is a large crater with a bright central peak and a floor partially covered with very dark material. This may be icy, carbon-rich material erupted onto the crater floor sometime after the crater formed. Another striking topographic feature is a large mountain, about 6 km (4 mi) high, peeking out on the lower left limb. The Voyager project is managed for NASA by the Jet Propulsion Laboratory. |
| Date |
01.25.1986 |
|
Bright patches on Ariel
| Title |
Bright patches on Ariel |
| Description |
Distinct bright patches are visible on Ariel, the brightest of Uranus' five largest satellites. Voyager 2 obtained this image Jan. 22, 1986, from a distance of 2.52 million kilometers (1.56 million miles). The clear-filter image, obtained with the narrow-angle camera, shows a resolution of 47 km (29 miles). Ariel is about 1,300 km (800 mi) in diameter. This image shows several distinct bright areas that reflect nearly 45 percent of the incident sunlight, on average, the satellite displays a reflectivity of about 25-30 percent. The bright areas are probably fresh water ice, perhaps excavated by impacts. The south pole of Ariel is slightly off center of the disk in this view. Voyager 2 will obtain its best views of the satellite on Jan. 24, at a closest-approach distance of 127,000 km (79,000 mi). The Voyager project is managed for NASA by the Jet Propulsion Laboratory. |
| Date |
01.23.1986 |
|
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