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NASA TV's This Week at NASA,
…
* Administrator Charlie Bold
…
01/08/2010
| Description |
* Administrator Charlie Bolden joined President Obama at a special White House ceremony honoring educators from across the country for their excellence in mathematics, science teaching and mentoring. The event was part of the President's ''Educate to Innovate'' campaign to boost student achievement in STEM subjects: science, technology, engineering and math. * More than 3,500 astronomers and students gathered in Washington for the annual meeting of the American Astronomical Society. This year's hot topics included the discovery of ''hot Jupiters",-- five new exoplanets detected by the Kepler telescope in deep space. These discoveries range in size from Neptune to larger than Jupiter and are known as ''hot Jupiters" because of their mass and extreme temperatures, 2,200 to 3,000 degrees Fahrenheit, they are far too hot to sustain life. * Space shuttle Endeavour moved from the Kennedy Space Center's Vehicle Assembly Building to Launch Pad 39A, signaling the start of STS-130's upcoming mock launch countdown activities. Endeavour's astronauts and ground crews will participate in a launch dress rehearsal, known as the Terminal Countdown Demonstration Test, starting Jan. 19. The test provides shuttle crews an opportunity to participate in various simulated countdown activities, including equipment familiarization and emergency training. STS-130 is scheduled to launch to the International Space Station on February 7 at 4:39 a.m. EST. * STS-130 will also take to the ISS a moon rock brought back from the lunar surface 40 years ago during the historic Apollo 11 mission, it'll be accompanied back to space by a small piece of the Earth's highest mountain. That rock was brought back from Mt. Everest last May by former NASA astronaut Scott Parazynski, who'd carried the Apollo lunar sample on his trek up the 29-thousand and 35-foot-high mountain. * STS-129 Mission Specialists Leland Melvin and Bobby Satcher were among the riders of a flower-adorned Space Odyssey float in this year's Rose Parade in Pasadena, California. |
| Date |
01/08/2010 |
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Pale Blue Orb (1)
| Description |
Pale Blue Orb |
| Full Description |
Not since NASA's Voyager 1 spacecraft saw our home as a pale blue dot from beyond the orbit of Neptune has Earth been imaged in color from the outer solar system. Now, Cassini casts powerful eyes on our home planet, and captures Earth, a pale blue orb -- and a faint suggestion of our moon -- among the glories of the Saturn system. Earth is captured here in a natural color portrait made possible by the passing of Saturn directly in front of the sun from Cassini's point of view. At the distance of Saturn's orbit, Earth is too narrowly separated from the sun for the spacecraft to safely point its cameras and other instruments toward its birthplace without protection from the sun's glare. The Earth-and-moon system is visible as a bright blue point on the right side of the image above center. Here, Cassini is looking down on the Atlantic Ocean and the western coast of north Africa. The phase angle of Earth, seen from Cassini is about 30 degrees. A magnified view of the image taken through the clear filter (monochrome) shows the moon as a dim protrusion to the upper left of Earth. Seen from the outer solar system through Cassini's cameras, the entire expanse of direct human experience, so far, is nothing more than a few pixels across. Earth no longer holds the distinction of being our solar system's only "water world," as several other bodies suggest the possibility that they too harbor liquid water beneath their surfaces. The Saturnian moon, Enceladus, is among them, and is also captured on the left in this image (see inset), with its plume of water ice particles and swathed in the blue E ring which it creates. Delicate fingers of material extend from the active moon into the E ring. See Ghostly Fingers of Enceladus, for a more detailed view of these newly-revealed features. The narrow tenuous G ring and the main rings are seen at the right. The view looks down from about 15 degrees above the un-illuminated side of the rings. Images taken using red, green and blue spectral filters were combined to create this view. The image was taken by the Cassini spacecraft wide-angle camera on Sept. 15, 2006, at a distance of approximately 2.1 million kilometers (1.3 million miles) from Saturn and at a sun-Saturn-spacecraft angle of almost 179 degrees. Image scale is 129 kilometers (80 miles) per pixel. At this time, Cassini was nearly 1.5 billion kilometers (930 million miles) from Earth. 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 operations center is based at the Space Science Institute in Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov ., The Cassini imaging team homepage is at http://ciclops.org . Credit: NASA/JPL/Space Science Institute |
| Date |
September 19, 2006 |
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Persistent Arc
| 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 movie shows a bright arc of material flashing around the edge of Saturn's G ring, a tenuous ring outside the main ring system. The arc is the same feature identified in images of the G ring taken in May 2005 (see Rings image titled "Arc in the Tenuous G Ring"). Scientists have seen the arc a handful of times over the past year, and it always appears to be a few times brighter than the rest of the ring and very tightly confined to a narrow strip along the inside edge of the G ring. Imaging team members believe that this feature is long-lived and may be held together by resonant interactions with the moon Mimas of the type that corral similar ring arcs around Neptune. The movie consists of 15 frames acquired every half hour over a period of seven-and-a-half hours. The version in the lower panel is vertically stretched by a factor of five to make the arc easier to see. The clear-filter images in this movie sequence were acquired by the Cassini spacecraft narrow-angle camera on April 25, 2006, at a distance of 2 million kilometers (1.2 million miles) from Saturn. The image scale on the sky at the distance of Saturn is about 24 kilometers (15 miles) 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 operations center is based at the Space Science Institute in Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org . Credit: NASA/JPL/Space Science Institute |
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Phoebe's Mineral Distributio
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| Description |
Phoebe's Mineral Distribution |
| Full Description |
These set of images were created during the Phoebe flyby on June 11, 2004. The images show the location and distribution of water-ice, ferric iron, carbon dioxide and an unidentified material on the tiny moon of Saturn. The first image was taken with Cassini's narrow angle camera and is shown for comparison purposes only. The other images were taken by the visual and infrared mapping spectrometer onboard Cassini. The infrared image of Phoebe obtained at a distance of about 16,000 km (10,000 miles) shows a large range of bright and dark features. The resolution of the image is about 4 km (2.5 miles). carbon dioxide on the surface of Phoebe is distributed globally, although it appears to be more prevalent in the darker regions of the satellite. The existence of carbon dioxide strongly suggests that Phoebe did not originate in the asteroid belt, but rather in much colder regions of the Solar System such as the Kuiper Belt. The Kuiper Belt is a vast reservoir of small, primitive bodies beyond the orbit of Neptune. An unidentified substance also appears to be more abundant in the darker regions. A map showing the distribution of water ice (blue), ferric iron (red), which is common in minerals on Earth and other planets, and the unidentified material (green). Water ice is associated with the brighter regions, while the other two materials are more abundant in the darker regions. 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 Cassini-Huygens mission for NASA's Office of Space Science, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The visual and infrared mapping spectrometer team is based at the University of Arizona, Tucson. For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and the visual and infrared mapping spectrometer home page at http://wwwvims.lpl.arizona.edu/ . Image Credit: NASA/JPL/University of Arizona |
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Phoebe Hi-Resolution Mosaic
| Description |
Phoebe Hi-Resolution Mosaic |
| Full Description |
During its historic close encounter with Phoebe, the Cassini spacecraft captured a series of high resolution images of the small moon, six of which have been put together to create this mosaic. Phoebe shows an unusual variation in brightness over its surface due to the existence on some crater slopes and floors of bright material - thought to contain ice - on what is otherwise one of the darkest known bodies in the solar system. Bright streaks on the rim of the large crater in the North (up in this image) may have been revealed by the collapse of overlying darker material from the crater wall. The large crater below right-of-center shows evidence of layered deposits of alternating bright and dark material. A possible mechanism for this apparent layering was discussed in an earlier image release. Hints of Phoebe's irregular topography can be seen peeking out from the shadows near the lower left and upper left parts of the image. These are real features - possibly crater rims or mountain peaks - that are just being hit by the first light of sunrise on Phoebe. Phoebe's surface shows many large- and small-scale craters. The emerging view of Phoebe is that it might have been part of an ancestral population of icy, comet-like bodies, some of which now reside in the Kuiper Belt beyond Neptune. The images in this mosaic were taken in visible light with the narrow-angle camera at distances ranging from 15,974 kilometers (9,926 miles) to 12,422 kilometers (7,719 miles). The image scale is 74 meters (243 feet) per pixel. Contrast in the image has been enhanced slightly to improve visibility. 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 Cassini-Huygens mission for NASA's Office of Space Science, 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 and the Cassini imaging team home page, http://ciclops.org . Image Credit: NASA/JPL/Space Science Institute |
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Neptune Moon
| title |
Neptune Moon |
| description |
Scientists used this faint, fuzzy image to pinpoint one of three new Neptunian moons more than 4 billion km (2.8 billion miles) from the Sun. This is S/2002 N1 as seen by the 4-meter Blanco telescope at Cerro Tololo Inter-American Observatory in Chile. |
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Moons of the Solar System
| title |
Moons of the Solar System |
| description |
All the planetary moons in our solar system are shown here at their correct relative size and true color. Their diversity of size and appearance is testament to the unique and fascinating geologic history that each of these bodies has undergone. Two of the moons are larger than the planet Mercury, and eight of them are larger than Pluto. Earth's Moon is the fifth largest of the set, with a diameter of 3476 kilometers (2160 miles). Most of the moons are thought to have formed from a disk of debris left over from formation of the planet they orbit. However Triton, Neptune's largest moon, and several of the smallest moons, including the moons of Mars, are thought to be captured planetesimals that formed elsewhere in the solar system. Earth's Moon is thought to have formed from the debris ejected from a roughly Mars-sized object colliding with the early Earth, perhaps a unique event in the history of the solar system. The moons are organized on the diagram by the planet they orbit (top to bottom with increasing distance from the Sun) and their position relative to the planet (left to right with increasing distance from the planet). Below is a listing of the names of all the moons and the planets they orbit. Most moons are named for mythological characters associated with the character the planet is named for. While most of the planets are named for Roman characters (with the exceptions of Pluto and Uranus), most of the moon have names from Greek mythology. For example, Phobos and Deimos are the sons of Ares, the Greek version of Mars. Jupiter?s moons are all named for lovers and other close associates of Zeus (Jupiter). Saturn?s moons are named for Titans, the race that included Cronos (Saturn), Zeus? father. Neptune?s moons are named for mythological characters associated with water, and Charon was the ferryman of the dead who brought people to Pluto?s realm. By tradition, the discoverer of a moon gets to name it (now subject to approval by the International Astronomical Union). The son of the discoverer of the first two moons of Uranus (Sir William Herschel) decided to name Uranus? moons not for mythological characters, but instead for the king and queen of fairies in Shakespear?s A Midsummer Night?s Dream . This began a tradition whereby all uranian satellites are named for fairy characters in English drama. To read more about the names of the planets and their satellites, go to the U.S. Geological Survey?s nomenclature guide at http://wwwflag.wr.usgs.gov/USGSFlag/Space/nomen/append7.html . *Earth* Moon *Mars * Phobos, Deimos *Jupiter* Metis, Adrastea, Amalthea, Thebe, Io, Europa, Ganymede, Callisto, Leda, Himalia, Lysithea, Elara, Ananke, Carme, Pasiphae, Sinope *Saturn * Pan, Atlas, Prometheus, Pandora, Epimetheus, Janus, Mimas, Enceladus, Tethys, Calypso, Telesto, Dione, Helene, Rhea, Titan, Hyperion, Iapetus, Phoebe *Uranus * Cordelia, Ophelia, Bianca, Cressida, Desdemona, Juliet, Portia, Rosalind, Belinda, Puck, Miranda,, Ariel, Umbriel, Titania, Oberon *Neptune* Naiad, Thalassa, Despina, Galatea, Larissa, Proteus, Triton, Nereid *Pluto * Charon *Image Credit*: Image processing by Tim Parker (Jet Propulsion Laboratory) and Paul Schenk and Robert Herrick (Lunar and Planetary Institute), based on NASA images. |
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Pale Blue Orb (2)
| title |
Pale Blue Orb (2) |
| date |
09.15.2006 |
| description |
Not since NASA's Voyager 1 spacecraft saw our home as a pale blue dot from beyond the orbit of Neptune has Earth been imaged in color from the outer solar system. Now, Cassini casts powerful eyes on our home planet, and captures Earth, a pale blue orb -- and a faint suggestion of our moon -- among the glories of the Saturn system. Earth is captured here in a natural color portrait made possible by the passing of Saturn directly in front of the sun from Cassini's point of view. At the distance of Saturn's orbit, Earth is too narrowly separated from the sun for the spacecraft to safely point its cameras and other instruments toward its birthplace without protection from the sun's glare. The Earth-and-moon system is visible as a bright blue point on the right side of the image above center. Here, Cassini is looking down on the Atlantic Ocean and the western coast of north Africa. The phase angle of Earth, seen from Cassini is about 30 degrees. A magnified view of the image taken through the clear filter (monochrome) shows the moon as a dim protrusion to the upper left of Earth. Seen from the outer solar system through Cassini's cameras, the entire expanse of direct human experience, so far, is nothing more than a few pixels across. Earth no longer holds the distinction of being our solar system's only "water world," as several other bodies suggest the possibility that they too harbor liquid water beneath their surfaces. The Saturnian moon, Enceladus, is among them, and is also captured on the left in this image, with its plume of water ice particles and swathed in the blue E ring which it creates. Delicate fingers of material extend from the active moon into the E ring. See Ghostly Fingers of Enceladus [ http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2276 ], for a more detailed view of these newly-revealed features. The narrow tenuous G ring and the main rings are seen at the right. The view looks down from about 15 degrees above the un-illuminated side of the rings. Images taken using red, green and blue spectral filters were combined to create this view. The image was taken by the Cassini spacecraft wide-angle camera on Sept. 15, 2006, at a distance of approximately 2.1 million kilometers (1.3 million miles) from Saturn and at a sun-Saturn-spacecraft angle of almost 179 degrees. Image scale is approximately 250 kilometers (155 miles) per pixel. At this time, Cassini was nearly 1.5 billion kilometers (930 million miles) from Earth. 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 operations center is based at the Space Science Institute in Boulder, Colo. For, more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov [ http://saturn.jpl.nasa.gov ] . The Cassini imaging team homepage is at http://ciclops.org [ http://ciclops.org ] . Credit: NASA/JPL/Space Science Institute |
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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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Phoebe's Mineral Map
| title |
Phoebe's Mineral Map |
| date |
06.11.2004 |
| description |
This set of images were created during the Cassini spacecraft's Phoebe flyby on June 11, 2004. The images show the location and distribution of water-ice, ferric iron, carbon dioxide and an unidentified material on the tiny moon of Saturn. The first image was taken with Cassini's narrow angle camera and is shown for comparison purposes only. The other images were taken by the visual and infrared mapping spectrometer onboard Cassini. The infrared image of Phoebe obtained at a distance of about 16,000 km (10,000 miles) shows a large range of bright and dark features. The resolution of the image is about 4 km (2.5 miles). carbon dioxide on the surface of Phoebe is distributed globally, although it appears to be more prevalent in the darker regions of the satellite. The existence of carbon dioxide strongly suggests that Phoebe did not originate in the asteroid belt, but rather in much colder regions of the Solar System such as the Kuiper Belt. The Kuiper Belt is a vast reservoir of small, primitive bodies beyond the orbit of Neptune. An unidentified substance also appears to be more abundant in the darker regions. A map showing the distribution of water ice (blue), ferric iron (red), which is common in minerals on Earth and other planets, and the unidentified material (green). Water ice is associated with the brighter regions, while the other two materials are more abundant in the darker regions. *Image Credit*: NASA/JPL/University of Arizona |
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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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Montage of Neptune and Trito
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| Title |
Montage of Neptune and Triton |
| Full Description |
This computer generated montage shows Neptune as it would appear from a spacecraft approaching Triton, Neptune's largest moon at 2706 km (1683 mi) in diameter. The wind and sublimation eroded south polar cap of Triton is shown at the bottom of the Triton image, a cryovolcanic terrain at the upper right, and the enigmatic "cantaloupe terrain" at the upper left. Triton's surface is mostly covered by nitrogen frost mixed with traces of condensed methane, carbon dioxide, and carbon monoxide. The tenuous atmosphere of Triton, though only about one hundredth of one percent of Earth's atmospheric density at the surface, is thick enough to produce wind-deposited streaks of dark and bright materials of unknown composition in the south polar cap region. The southern polar cap was sublimating at the time of the Voyager 2 flyby, as indicated by the irregular and eroded appearance of the edge of the cap. |
| Date |
01/06/1990 |
| NASA Center |
Jet Propulsion Laboratory |
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Neptune and Tritron
| Title |
Neptune and Tritron |
| Full Description |
This image was returned by the Voyager 2 spacecraft on July 3, 1989, when it was 76 million kilometers (47 million miles) from Neptune. The planet and its largest satellite, Triton, are captured in the field of view of Voyager's narrow-angle camera through violet, clear and orange filters. Triton appears in the lower right corner at about 5 o'clock relative to Neptune. Measurements from Voyager images show Triton to be between 1,400 and 1,800 kilometers (about 870 to 1,100 miles) in radius with a surface that is about as bright as freshly fallen snow. Because Triton is barely resolved in current narrow-angle images, it is too early to see features on its surface. Scientists believe Triton has at least a small atmosphere of methane and possibly other gases. During its closest approach to Triton on August 25, 1989, Voyager provided high-resolution views of the moon's icy surface and reveal whether Triton's atmosphere has clouds. JPL manages the Voyager Project for NASA's Office of Space Science and Applications, Washington, DC. |
| Date |
07/27/1989 |
| NASA Center |
Jet Propulsion Laboratory |
|
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
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| 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 |
|
Global Color Mosaic of Trito
…
| Title |
Global Color Mosaic of Triton |
| Full Description |
Global color mosaic of Triton, taken in 1989 by Voyager 2 during its flyby of the Neptune system. Color was synthesized by combining high- resolution images taken through orange, violet, and ultraviolet filters, these images were displayed as red, green, and blue images and combined to create this color version. With a radius of 1,350 (839 mi), about 22% smaller than Earth's moon, Triton is by far the largest satellite of Neptune. It is one of only three objects in the Solar System known to have a nitrogen-dominated atmosphere (the others are Earth and Saturn's giant moon, Titan). Triton has the coldest surface known anywhere in the Solar System (38 K, about -391 degrees Farenheit), it is so cold that most of Triton's nitrogen is condensed as frost, making it the only satellite in the Solar System known to have a surface made mainly of nitrogen ice. The pinkish deposits constitute a vast south polar cap believed to contain methane ice, which would have reacted under sunlight to form pink or red compounds. The dark streaks overlying these pink ices are believed to be an icy and perhaps carbonaceous dust deposited from huge geyser-like plumes, some of which were found to be active during the Voyager 2 flyby. The bluish-green band visible in this image extends all the way around Triton near the equator, it may consist of relatively fresh nitrogen frost deposits. The greenish areas include what is called the cataloupe terrain, whose origin is unknown, and a set of "cryovolcanic" landscapes apparently produced by icy-cold liquids (now frozen) erupted from Triton's interior. |
| Date |
05/01/1980 |
| NASA Center |
Jet Propulsion Laboratory |
|
Hubble Sheds Light on the "F
…
| Title |
Hubble Sheds Light on the "Faint Blue Galaxy" Mystery |
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Hubble Follows Rapid Changes
…
| Title |
Hubble Follows Rapid Changes in Jupiter's Aurora |
|
Asteroid or Mini-Planet? Hub
…
| Title |
Asteroid or Mini-Planet? Hubble Maps the Ancient Surface of Vesta |
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Hubble Uncovers Dust Disk ar
…
| Title |
Hubble Uncovers Dust Disk around a Massive Black Hole |
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Hubble Uncovers Dust Disk ar
…
| Title |
Hubble Uncovers Dust Disk around a Massive Black Hole |
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Hubble Uncovers Dust Disk ar
…
| Title |
Hubble Uncovers Dust Disk around a Massive Black Hole |
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Hubble Simulcast Links Outer
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| Title |
Hubble Simulcast Links Outer Space to Cyberspace |
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Hubble Space Telescope Helps
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| Title |
Hubble Space Telescope Helps Find Evidence that Neptune's Largest Moon Is Warming Up |
|
Farthest, Faintest Solar Sys
…
| Title |
Farthest, Faintest Solar System Objects Found Beyond Neptune |
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Hubble Confirms New Moons of
…
| Title |
Hubble Confirms New Moons of Pluto |
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First ESA Faint Object Camer
…
| Title |
First ESA Faint Object Camera Science Images Pluto - the "Double Planet |
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A89-7024
Photographer : JPL P-34679 R
…
8/23/89
| Description |
Photographer : JPL P-34679 Range : 2 million km. ( 1.2 million miles ) In this Voyager 2, wide-angle image, the two main rings of Neptune can be clearly seen. In the lower part of the frame, the originally-announced ring arc, consisting of three distinct features, is visible. This feature covers about 35 degrees of longitude and has yet to be radially resolved in Voyager Images. from higher resolution images it is known that this region contains much more material than the diffuse belts seen elsewhere in its orbit, which seem to encircle the planet. This is consistent with the fact that ground-based observations of stellar occultations by the rings show them to be very broken and clumpy. The more sensitive, wide-angle camera is revealing more widely distributed but fainter material. Each of these rings of material lies just outside of the orbit of a newly discovered moon. One of these moons, 1989N2, may be seen in the upper right corner. The moon is streaked by its orbital motion, whereas the stars in the frame are less smeared. the dark area around the bright moon and star are artifacts of the processing required to bring out the faint rings. |
| Date |
8/23/89 |
|
A89-7042
Photographer: JPL P-34578 BW
…
8/11/89
| Description |
Photographer: JPL P-34578 BW One of two new ring arcs, or partial rings, discovered by Voyager 2, is faintly visible just outside the orbit of the Neptunian moon 1989N4.The 155-second exposure taken by the spacecraft's narrow-angle camera shows the glare of an overexposed Neptune to the right of the moon and ring arc. The two bright streaks below the moon and ring arc are stars. The ring arc is approximately 50,000 kilometers (30,000 miles) long. The second ring arc, not apparent here, is about 10,000 kilometers (6,000 miles) long and is assoiciated with moon 1989N3. The ring arc, along with 1989N4, orbits about 62,000 kilometers (38,000 miles) from the planet's cloud tops. Astronomers long suspected the existence of such an irregular ring system around Neptune. Data from repeated ground-based observations hinted at the existence of irregular strands of partial rings orbiting Neptune. Voyager's photographs of the ring arcs are the first photographic evidence that such a ring system exists. Voyager scientists said the ring arcs may be comprised of debris associated with the nearby moons, or may be the remnants of moons that have been torn apart or ground down through collisions. Close-up studies of the ring arcs by Voyager 2 will help determine their composition. |
| Date |
8/11/89 |
|
AC89-7002
Photographer : JPL P-34615 T
…
8/21/89
| Description |
Photographer : JPL P-34615 These three color images of Triton were taken at three different orbital longitudes to show different faces of the neptune moon. the overall pinkish cast of the images may be due to the presence of reddish material on Triton produced by irradiation of methane gas and ice on Triton. In these pictures the south pole is at roughly 6 o'clock, about 1/6th of the way from the bottom. Near the top of the left on Triton's equator are several large dark spots that are probably suface markings. These markings rotate with a 5.88-day orbital period of Triton. The left image has a central longitude 288 degrees, the center at 351 degrees ( nearly the hemisphere that will be seen at Voyager's closest approach to Triton), and the right image is at 35 degrees logitude. |
| Date |
8/21/89 |
|
Eris: The Largest Known Dwar
…
| Title |
Eris: The Largest Known Dwarf Planet |
| Explanation |
Is Pluto the largest dwarf planet? No! Currently, the largest known dwarf planet is (136199) Eris [ http://en.wikipedia.org/wiki/136199_Eris ], renamed last week from 2003 UB313 [ http://antwrp.gsfc.nasa.gov/apod/ap060207.html ]. Eris is just slightly larger than Pluto, but orbits as far as twice Pluto [ http://antwrp.gsfc.nasa.gov/apod/ap060903.html ]'s distance from the Sun. Eris is shown above [ http://www.keckobservatory.org/view_album.php?album_id=4 ] in an image taken by a 10-meter Keck Telescope [ http://antwrp.gsfc.nasa.gov/apod/ap971227.html ] from Hawaii [ http://antwrp.gsfc.nasa.gov/apod/ap951216.html ], USA [ https://www.cia.gov/cia/publications/factbook/geos/us.html ]. Like Pluto, Eris has a moon, which has been officially named [ http://cfa-www.harvard.edu/iau/special/08747.pdf ] by the International Astronomical Union [ http://www.iau.org/ ] as (136199) Eris I (Dysnomia). Dysnomia [ http://en.wikipedia.org/wiki/Dysnomia_%28moon%29 ] is visible above just to the right of Eris. Dwarf planets [ http://en.wikipedia.org/wiki/Dwarf_planet ] Pluto and Eris are trans-Neptunian objects [ http://www.planetary.org/explore/topics/trans_neptunian_objects/ ] that orbit in the Kuiper belt [ http://www.ifa.hawaii.edu/~jewitt/kb.html ] of objects past Neptune. Eris [ http://antwrp.gsfc.nasa.gov/apod/ap050801.html ] was discovered in 2003, and is likely composed of frozen water-ice and methane [ http://en.wikipedia.org/wiki/Methane ]. Since Pluto's recent demotion by the IAU [ http://en.wikipedia.org/wiki/International_Astronomical_Union ] from planet to dwarf planet status, Pluto [ http://voyagesolarsystem.org/gallery/gallery_10.html ] has recently also been given a new numeric designation: (134340) Pluto. Currently, the only other officially designated "dwarf planet" is (1) Ceres [ http://antwrp.gsfc.nasa.gov/apod/ap060821.html ]. |
|
Titania's Trenches
| Title |
Titania's Trenches |
| Explanation |
British astronomer Sir William Herschel [ http://star.arm.ac.uk/history/herschel.html ] discovered Titania and Oberon in January of 1787. He wasn't reading Shakespeare's [ http://the-tech.mit.edu/Shakespeare/works.html ]"A Midsummer Night's Dream" though, he was making the first telescopic observations of moons of the planet Uranus [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/uranus.html ] (a planet which he himself discovered in 1781 [ http://www-groups.dcs.st-and.ac.uk/~history/ HistTopics/Neptune_and_Pluto.html ]). In January of 1986, nearly 200 years later, NASA's robot explorer Voyager 2 became the only spacecraft to visit the remote Uranian [ http://antwrp.gsfc.nasa.gov/apod/ap990531.html ] system [ http://antwrp.gsfc.nasa.gov/apod/ap971103.html ]. Above is Voyager's highest resolution picture of Titania [ http://photojournal.jpl.nasa.gov/cgi-bin/ PIAGenCatalogPage.pl?PIA00039 ], Uranus' largest moon. The picture is a composite of two images recorded from a distance of 229,000 miles. The icy, rocky world [ http://antwrp.gsfc.nasa.gov/apod/ap960304.html ] is seen to be covered with impact craters. A prominent system of fault valleys, some nearly 1,000 miles long, is visible as trench-like features near the terminator (shadow line). Deposits of highly reflective material which may represent frost can be seen along the sun-facing valley walls. The large impact crater near the top, known as Gertrude [ http://wwwflag.wr.usgs.gov/USGSFlag/Space/nomen/uranus/titacrat.html ], is about 180 miles across. At the bottom the 60 mile wide fault valley, Belmont Chasma [ http://wwwflag.wr.usgs.gov/USGSFlag/Space/nomen/uranus/titachas.html ], cuts into crater Ursula. Titania itself [ http://wwwflag.wr.usgs.gov/USGSFlag/Space/wall/titania.html ] is 1,000 miles in diameter. |
|
Triton: Neptune's Largest Mo
…
| Title |
Triton: Neptune's Largest Moon |
| Explanation |
In October of 1846, William Lassell [ http://en.wikipedia.org/wiki/William_Lassell ] was observing the newly discovered planet Neptune [ http://www.seds.org/nineplanets/nineplanets/neptune.html ]. He was attempting to confirm his observation, made just the previous week, that Neptune [ http://en.wikipedia.org/wiki/Neptune ] had a ring. But this time he discovered that Neptune had a satellite as well. Lassell soon proved that the ring was a product of his new telescope's distortion, but the satellite Triton [ http://www.seds.org/nineplanets/nineplanets/triton.html ] remained. The above picture [ http://nssdc.gsfc.nasa.gov/imgcat/html/object_page/vg2_p34764.html ] of Triton [ http://en.wikipedia.org/wiki/Triton_%28moon%29 ] was taken in 1989 by the only spacecraft ever to pass Triton [ http://antwrp.gsfc.nasa.gov/apod/ap950805.html ]: Voyager [ http://antwrp.gsfc.nasa.gov/apod/ap020831.html ] 2. Voyager 2 found fascinating terrain [ http://nssdc.gsfc.nasa.gov/photo_gallery/caption/triton_close.txt ], a thin atmosphere, and even evidence for ice volcanoes [ http://antwrp.gsfc.nasa.gov/apod/ap010629.html ] on this world of peculiar orbit and spin. Ironically, Voyager 2 also confirmed the existence of complete thin rings [ http://nssdc.gsfc.nasa.gov/imgcat/html/object_page/vg2_1135023.html ] around Neptune - but these would have been quite invisible [ http://www.youtube.com/watch?v=OQWxIrSRDQQ ] to Lassell! |
|
Pluto: New Horizons
| Title |
Pluto: New Horizons |
| Explanation |
Pluto's [ http://dosxx.colorado.edu/plutohome.html ] horizon spans the foreground in this artist's vision, gazing sunward across that distant and not yet explored [ http://antwrp.gsfc.nasa.gov/apod/ap960212.html ] world. Titled New Horizons, the painting also depicts Pluto's [ http://maps.jpl.nasa.gov/pluto.html ] companion, Charon [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/ pluto.html#charon ], as a darkened, ghostly apparition with a luminous crescent [ http://www.lowell.edu/users/buie/pluto/chphases.html ] against a starry background. Beyond Charon [ http://www.jpl.nasa.gov/ice_fire/CharonDiscovery.htm ], the diminished Sun is immersed in a flattened cloud of zodiacal dust [ http://antwrp.gsfc.nasa.gov/apod/ap010912.html ]. Here, Pluto's ruddy colors are based on existing astronomical [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query? bibcode=2000DPS....32.4601Y ] observations while imagined but scientifically [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query? bibcode=1999AJ....117.1063Y ] tenable details provided by the artist include high atmospheric cirrus and dark plumes from surface vents, in analogy to Neptune's large moon Triton [ http://antwrp.gsfc.nasa.gov/apod/ap950805.html ] explored by the Voyager [ http://vraptor.jpl.nasa.gov/voyager/voyager_fs.html ] 2 spacecraft in 1989. Craters suggest bombardment by Kuiper Belt [ http://www.ifa.hawaii.edu/faculty/jewitt/kb.html ] objects, a newly understood population of [ http://www.solstation.com/stars/kuiper.htm ] outer solar system bodies likely related to [ http://antwrp.gsfc.nasa.gov/apod/ap010830.html ] the Pluto-Charon system [ http://www.jpl.nasa.gov/ice_fire//alans.htm ]. NASA is now considering a future robotic reconnaissance mission to [ ftp://ftp.hq.nasa.gov/pub/pao/pressrel/2001/01-114.txt ] Pluto-Charon and the Kuiper Belt which could reach the distant worlds late in the next decade. |
|
Jupiter's Rings
| Title |
Jupiter's Rings |
| Explanation |
Astronomers using NASA's Voyager [ http://nssdc.gsfc.nasa.gov/planetary/voyager.html ] spacecraft to search for a ring system around Jupiter discovered these faint rings in 1979. Unlike Saturn's bright rings which are composed of chunks of rock and ice, Jupiter's rings [ http://ringside.arc.nasa.gov/www/jupiter/jupiter.html ] appear to consist of fine particles of dust. One possibility is that the dust is produced by impacts with Jupiter's inner moons. This false color image has been computer enhanced. The gas giant planets, Jupiter, Saturn, Uranus, and Neptune are all known to have rings. For more information about planetary ring systems see the Planetary Rings Node [ http://ringside.arc.nasa.gov/ ]. Tomorrow's picture: A Volcanic Moon |
|
Neptune: Big Blue Giant
| Title |
Neptune: Big Blue Giant |
| Explanation |
This picture was taken by the Voyager 2 [ http://nssdc.gsfc.nasa.gov/planetary/voyager.html ] spacecraft in 1986 - the only spacecraft ever to visit Neptune. Neptune [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/neptune.html ] will be the farthest planet from the Sun [ http://antwrp.gsfc.nasa.gov/apod/ap950813.html ] until 1999, when the elliptical orbit of Pluto will cause it to once again resume this status. Neptune [ http://www.c3.lanl.gov/~cjhamil/SolarSystem/neptune.html ], like Uranus [ http://antwrp.gsfc.nasa.gov/apod/ap950816.html ], is composed mostly of liquid water, methane and ammonia, is surrounded by a thick gas atmosphere of mostly hydrogen and helium, and has many moons and rings. Neptune [ http://nssdc.gsfc.nasa.gov/photo_gallery/photogallery-neptune.html ]'s moon Triton [ http://antwrp.gsfc.nasa.gov/apod/ap950805.html ] is unlike any other and has active volcanoes. The nature of Triton [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/triton.html ]'s unusual orbit around Neptune is the focus of much discussion and speculation. Tomorrow's picture: Pluto: The Frozen Planet |
|
Pluto: The Frozen Planet
| Title |
Pluto: The Frozen Planet |
| Explanation |
The Hubble Space Telescope imaged [ http://www.ast.cam.ac.uk/HST/press/pluto.html ] Pluto and its moon Charon in 1994. Pluto [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/pluto.html ] is usually the most distant planet from the Sun [ http://antwrp.gsfc.nasa.gov/apod/ap950813.html ] but because of its elliptic orbit Pluto crossed inside of Neptune [ http://antwrp.gsfc.nasa.gov/apod/ap950817.html ]'s orbit in 1979 and will cross back out again in 1999. Compared to the other planets, very little is known about Pluto. Pluto [ http://www.c3.lanl.gov/~cjhamil/SolarSystem/pluto.html ] is smaller than any other planet and even smaller than several other planet's moons. From Pluto, the Sun is just a tiny point of light. Pluto [ http://dosxx.colorado.edu/plutohome.html ] is probably composed of frozen rock and ice, much like Neptune's moon Triton [ http://antwrp.gsfc.nasa.gov/apod/ap950805.html ]. Pluto has not yet been visited by a spacecraft, but a mission [ http://www.jpl.nasa.gov/pluto/ ] is being planned for the next decade. Tomorrow's picture: Our Solar System from Voyager |
|
Geysers on Triton
| Title |
Geysers on Triton |
| Explanation |
In August of 1989 NASA's Voyager 2 [ http://nssdc.gsfc.nasa.gov/planetary/voyager.html ] spacecraft passed by Neptune, the most distant of the solar system's gas giant planets. Its encounter with Neptune climaxed with its closest approach to Neptune's largest moon Triton. From a distance of about 24,000 miles the robot space probe surveyed Triton's surface, whose temperature averages nearly -400 degrees Fahrenheit, and discovered surprising evidence of a complex and active world. For example, the prominent dark streaks in this image seem to come from small volcanoes and may consist of nitrogen frost mixed with organic compounds ejected during geyser-like eruptions. For more information about Triton, see Calvin J. Hamilton's Triton page [ http://www.c3.lanl.gov/~cjhamil/SolarSystem/triton.html ]. Tomorrow's picture: Liftoff of Space Shuttle Columbia. |
|
Titan: Saturn's Smog Moon
| Title |
Titan: Saturn's Smog Moon |
| Explanation |
The largest moon of Saturn [ http://antwrp.gsfc.nasa.gov/apod/ap950705.html ] is a rare wonder. Titan is the only one of Saturn [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/titan.html ]'s moons with an atmosphere, and one of only two moons in the Solar System [ http://antwrp.gsfc.nasa.gov/apod/ap950819.html ] with this distinction (Neptune [ http://antwrp.gsfc.nasa.gov/apod/ap950817.html ]'s Triton [ http://antwrp.gsfc.nasa.gov/apod/ap950805.html ] is the other). Titan [ http://www.c3.lanl.gov/~cjhamil/SolarSystem/titan.html ]'s thick cloudy atmosphere is mostly nitrogen, like Earth [ http://antwrp.gsfc.nasa.gov/apod/ap950622.html ]'s, but contains much higher percentages of "smog-like" chemicals such as methane and ethane. The smog may be so thick that it actually rains "gasoline-like" liquids. The organic nature of some of the chemicals found in Titan's atmosphere cause some to speculate that Titan may harbor life! Because of its thick cloud cover, however, Titan's actual surface properties remain mysterious. Voyager [ http://vraptor.jpl.nasa.gov/voyager/voyager.html ] 1 flew by in 1980 taking the above picture, and recently much has been learned from Hubble Space Telescope observations [ http://www.stsci.edu/pubinfo/PR/94/55.html ]. The Cassini mission [ http://www.jpl.nasa.gov/mip/cassini.html ] currently scheduled for launch in 1997 will map Titan's surface, helping to solve some of its mysteries. |
|
Neptune's Moon Proteus
| Title |
Neptune's Moon Proteus |
| Explanation |
Proteus is the second largest moon of Neptune [ http://antwrp.gsfc.nasa.gov/apod/ap950817.html ] behind the mysterious Triton [ http://antwrp.gsfc.nasa.gov/apod/ap950805.html ]. Proteus was discovered only in 1982 by the Voyager 2 spacecraft. This is unusual since Neptune has a smaller moon - Nereid - which was discovered 33 years earlier from Earth. The reason Proteus [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/proteus.html ] was not discovered sooner is that its surface is very dark and it orbits much closer to Neptune. Proteus [ http://www.c3.lanl.gov/~cjhamil/SolarSystem/proteus.html ] has an odd box-like shape and were it even slightly more massive, its own gravity would cause it to reform itself into a sphere. |
|
Uranus' Largest Moon: Titani
…
| Title |
Uranus' Largest Moon: Titania |
| Explanation |
Titania's tortured terrain is a mix of valleys and craters. NASA's interplanetary robot spacecraft Voyager [ http://spacelink.msfc.nasa.gov/NASA.Projects/Planetary.Probes/Voyager/Mission.Summary ] 2 passed this moon of Uranus [ http://antwrp.gsfc.nasa.gov/apod/ap950816.html ] in 1986 and took the above photograph. The photograph was then transmitted back to earth by radio [ http://www.science.uwaterloo.ca/physics/p13news/number_2/maxnew-2.html ]. The valleys of Titania [ http://bang.lanl.gov/solarsys/titania.htm ] resemble those on Ariel [ http://antwrp.gsfc.nasa.gov/apod/ap960303.html ] indicate that Titania underwent some unknown tumultuous resurfacing event in its distant past. Although Titania [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/titania.html ] is Uranus' largest moon, it is still much smaller than Triton [ http://antwrp.gsfc.nasa.gov/apod/ap950805.html ] - the largest moon of Uranus' sister planet Neptune [ http://antwrp.gsfc.nasa.gov/apod/ap950817.html ]. Titania is essentially a large dirty iceball that orbits Uranus - it is composed of about half water-ice and half rock. Titania was discovered by William Hershel [ http://www.dsi.unimi.it/Users/Students/amoroso/sun/fortunes/life-e.html ] in 1787. |
|
Ringed Planet Uranus
| Title |
Ringed Planet Uranus |
| Explanation |
Yes it does look like Saturn, but Saturn is only one of four [ http://antwrp.gsfc.nasa.gov/apod/ap020616.html ] giant [ http://antwrp.gsfc.nasa.gov/apod/ap020215.html ] ringed [ http://antwrp.gsfc.nasa.gov/apod/ap981020.html ] planets [ http://ringmaster.arc.nasa.gov/neptune/neptune.html ] in our Solar System. And while Saturn has the brightest rings, this system of rings and moons actually belongs to planet Uranus, imaged here [ http://www.eso.org/outreach/press-rel/pr-2002/ phot-31-02.html ] in near-infrared light by the Antu [ http://antwrp.gsfc.nasa.gov/apod/ap000707.html ] telescope at the ESO Paranal Observatory in Chile. Since gas giant Uranus' [ http://www.seds.org/nineplanets/nineplanets/uranus.html ] methane-laced atmosphere absorbs sunlight at near-infrared wavelengths the planet appears substantially darkened, improving the contrast between the otherwise relatively bright planet and the normally faint rings. In fact, the narrow Uranian rings [ http://ringmaster.arc.nasa.gov/uranus/ uranus.html ] are all but impossible to see in visible light with earthbound telescopes and were discovered [ http://tdc-www.harvard.edu/occultations/ uranus25/ ] only in 1977 as careful astronomers noticed the then unknown rings blocking light from background stars. The rings are thought to be younger than 100 million years and may be formed of debris from the collision of a small moon with a passing comet or asteroid-like object. With moons [ http://antwrp.gsfc.nasa.gov/apod/ap000930.html ] named for characters [ http://antwrp.gsfc.nasa.gov/apod/ap990227.html ] in Shakespeare's plays, the distant ringed world Uranus [ http://vraptor.jpl.nasa.gov/voyager/vgrur_fs.html ] was last visited in 1986 by the Voyager 2 spacecraft. |
|
Old Faithful Meets Hale-Bopp
| Title |
Old Faithful Meets Hale-Bopp |
| Explanation |
As Comet Hale-Bopp leaves our Northern Skies, it provides us with yet another burst of joy. On May 11th the fading comet was photographed [ http://galileo.ivv.nasa.gov/comet/van56.html ] behind the famous "Old Faithful [ http://pcsel10.scu.edu/jshiau/coen296/old.html ]" water geyser of Yellowstone National Park [ http://volcano.und.nodak.edu/vwdocs/Parks/yellowstone/yellowstone.html ], Wyoming, USA, Planet Earth. Perhaps more familiar to Earth Dwellers than the dark geysers on Neptune [ http://www.seds.org/nineplanets/nineplanets/neptune.html ]'s moon Triton [ http://antwrp.gsfc.nasa.gov/apod/ap950805.html ], the gas geysers on Jupiter [ http://www.seds.org/nineplanets/nineplanets/jupiter.html ]'s moon Io [ http://antwrp.gsfc.nasa.gov/apod/ap970321.html ], and the dirty water geysers hypothesized on Jupiter's moon Europa [ http://antwrp.gsfc.nasa.gov/apod/ap970410.html ], Earth [ http://www.seds.org/nineplanets/nineplanets/earth.html ]'s Old Faithful is also reliable - every 60-80 minutes it gushes a plume of water and steam high into the air. Comet Hale-Bopp [ http://galileo.ivv.nasa.gov/comet/ ] will continue to be visible to observers in the Southern Hemisphere [ http://antwrp.gsfc.nasa.gov/apod/ap970515.html ] as it moves away from the Sun towards the outer Solar System. |
|
Neptune and Triton from Palo
…
| Title |
Neptune and Triton from Palomar |
| Explanation |
How's the weather on Neptune? Tracking major weather patterns [ http://vathena.arc.nasa.gov/curric/weather/hsweathr/patterns.html ] on the Solar System [ http://www.exploratorium.edu/ronh/solar_system/ ]'s outermost gas giant can help in the understanding of global weather patterns here on Earth [ http://antwrp.gsfc.nasa.gov/apod/ap010204.html ]. Each summer for the past five years, Neptune [ http://www.nineplanets.org/neptune.html ] has been imaged and major weather patterns studied. The latest picture, taken on September 15, is shown above in false color [ http://earthobservatory.nasa.gov:81/Library/glossary.php3?mode=alpha&seg=f&segend=h ]. Visible in pink near Neptune [ http://antwrp.gsfc.nasa.gov/apod/ap961028.html ]'s lower right is a new storm dubbed Annabelle that is several times larger than her terrestrial sister Isabel [ http://antwrp.gsfc.nasa.gov/apod/ap030916.html ], a concurrent storm system [ http://www.firstscience.com/site/articles/cornell.asp ] that occurred here on Earth. Although Isabel lasted a few weeks, no one knows how long [ http://antwrp.gsfc.nasa.gov/apod/ap011201.html ] Annabelle will endure. On the upper right is Neptune [ http://antwrp.gsfc.nasa.gov/apod/ap010619.html ]'s largest moon Triton [ http://antwrp.gsfc.nasa.gov/apod/ap991010.html ], an unusual moon [ http://www.nineplanets.org/triton.html ] that sports volcanoes that spew ice [ http://antwrp.gsfc.nasa.gov/apod/ap950805.html ]. |
|
Triton: Neptune's Largest Mo
…
| Title |
Triton: Neptune's Largest Moon |
| Explanation |
On October 10th, 1846, William Lassell was observing the newly discovered planet Neptune. He was attempting to confirm his observation, made just the previous week, that Neptune had a ring. But this time he discovered that Neptune had a satellite as well. Lassell soon proved that the ring was a product of his new telescope's distortion, but the satellite Triton remained. The above picture of Triton was taken in 1989 by the only spacecraft ever to pass Triton: Voyager 2. Voyager 2 found fascinating terrain, a thin atmosphere, and even evidence for ice volcanoes on this world of peculiar orbit and spin. Ironically, Voyager 2 also confirmed the existence of complete thin rings around Neptune - but these would have been quite invisible to Lassell! |
|
A Sky Full Of Planets
| Title |
A Sky Full Of Planets |
| Explanation |
Look up tonight [ http://www.cnn.com/TECH/9712/01/heavenly.show.ap/ ]. Just after sunset, the crescent moon and all five "naked-eye" planets (Mercury [ http://antwrp.gsfc.nasa.gov/apod/ap971130.html ], Venus [ http://antwrp.gsfc.nasa.gov/apod/ap971014.html ], Mars [ http://antwrp.gsfc.nasa.gov/apod/ap970528.html ], Jupiter [ http://antwrp.gsfc.nasa.gov/apod/ap971030.html ], and Saturn [ http://antwrp.gsfc.nasa.gov/apod/ap970829.html ]) will be visible (depending on your latitude), lying near our solar system's ecliptic plane [ http://antwrp.gsfc.nasa.gov/apod/ap970927.html ]. Venus and Jupiter will shine brilliantly as the brightest "stars" in the sky, but Mercury will be near the horizon and hard to see. A pair of binoculars will also reveal Uranus and Neptune and observers with a telescope and a good site may even be able to glimpse faint Pluto just above the Western horizon in the fading twilight (not shown on the chart above). Enjoy this lovely spectacle any clear night [ http://www.skypub.com/whatsup/dec97sky.html ] through about December 8. A similar gathering is expected in May 2000 [ http://www.skypub.com/special/alignmnt/whypanic.html ] but the planets will be hidden from view by the solar glare. A night sky as full of planets as this one will occur again though ... in about 100 years. |
|
Phoebe: Comet Moon of Saturn
| Title |
Phoebe: Comet Moon of Saturn |
| Explanation |
Was Saturn's moon Phoebe once a comet? Images from the robotic Cassini spacecraft [ http://saturn.jpl.nasa.gov/spacecraft/index.cfm ] taken two weeks ago when entering the neighborhood of Saturn [ http://www.nineplanets.org/saturn.html ] indicate that Phoebe [ http://www.nineplanets.org/phoebe.html ] may have originated in the outer Solar System [ http://www.nineplanets.org/overview.html ]. Phoebe's irregular surface [ http://antwrp.gsfc.nasa.gov/apod/ap040614.html ], retrograde orbit [ http://en.wikipedia.org/wiki/Retrograde_orbit ], unusually dark surface, assortment of large and small craters, and low average density appear consistent with the hypothesis [ http://saturn.jpl.nasa.gov/news/press-releases-04/20040614-pr-a.cfm ] that Phoebe was once part of the Kuiper belt [ http://www.ifa.hawaii.edu/faculty/jewitt/kb.html ] of icy comets beyond Neptune before being captured by Saturn. Visible in the above image [ http://photojournal.jpl.nasa.gov/catalog/PIA06064 ] of Phoebe are craters, streaks, and layered deposits of light and dark material. The image was taken from around 30,000 kilometers out from this 200-kilometer diameter moon [ http://www.space.com/scienceastronomy/phoebe_unveiled_040615.html ]. Late today, Cassini will begin to fire its engines [ http://saturn.jpl.nasa.gov/ ] to decelerate into orbit around Saturn. |
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Pluto: The Frozen Planet
| Title |
Pluto: The Frozen Planet |
| Explanation |
This portrait of Pluto [ http://oposite.stsci.edu/pubinfo/pr/94/17.html ] and its companion Charon [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/ pluto.html#charon ] was taken by the Hubble Space Telescope in 1994. Pluto is [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/pluto.html ] usually the most distant planet from the Sun [ http://antwrp.gsfc.nasa.gov/apod/ap960916.html ] but because of its eccentric orbit Pluto crossed inside of Neptune's [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/neptune.html ] orbit in 1979. On Thursday, February 11th, it crossed back out, recovering its status [ http://www.lowell.edu/users/buie/pluto/ ] as the most distant of nine planets [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/ ]. Pluto [ http://www.iau.org/PlutoPR.html ] is still considered to be a planet, although very little is known about it compared to other planets. Pluto [ http://antwrp.gsfc.nasa.gov/apod/ap980708.html ] is smaller than any other planet and even smaller than several other planet's moons. Pluto is [ http://dosxx.colorado.edu/plutohome.html ] probably composed of frozen rock and ice, much like Neptune's moon Triton [ http://antwrp.gsfc.nasa.gov/apod/ap971123.html ]. Pluto has not yet been visited by a spacecraft, but a mission is being planned [ http://www.jpl.nasa.gov/pluto/pkexprss.htm ] for the next decade. |
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Titan: Saturn's Smog Moon
| Title |
Titan: Saturn's Smog Moon |
| Explanation |
The largest moon of Saturn [ http://www.seds.org/nineplanets/nineplanets/saturn.html ] is a rare wonder. Titan [ http://www.seds.org/nineplanets/nineplanets/titan.html ] is the only one of Saturn's moons with an atmosphere, and one of only two moons in the Solar System [ http://www.seds.org/nineplanets/nineplanets/overview.html ] with this distinction (Neptune's Triton [ http://antwrp.gsfc.nasa.gov/apod/ap971123.html ] is the other). Titan's thick cloudy atmosphere is mostly nitrogen, like Earth's, but contains much higher percentages of "smog-like" chemicals such as methane and ethane. The smog may be so thick that it actually rains "gasoline-like" liquids. The organic nature of some of the chemicals found in Titan [ http://antwrp.gsfc.nasa.gov/apod/ap951021.html ]'s atmosphere cause some to speculate that Titan may harbor life! Because of its thick cloud cover, however, Titan's actual surface properties remain mysterious. Voyager 1 flew by in 1980 taking the above picture, and more recently much has been learned from observations [ http://oposite.stsci.edu/pubinfo/pr/94/55.html ] by the Hubble Space Telescope [ http://antwrp.gsfc.nasa.gov/apod/ap970306.html ]. The Cassini mission [ http://www.jpl.nasa.gov/cassini/ ] launched in 1997 will map Titan's surface in 2004, helping to solve some of its mysteries. |
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Possible Pluto Moons
| Title |
Possible Pluto Moons |
| Explanation |
In 1930 [ http://www.lowell.edu/press_room/releases/recent_releases/ PL_75_rls.html ], tiny, icy world Pluto was discovered [ http://antwrp.gsfc.nasa.gov/apod/ap970204.html ] orbiting in the distant solar system. In 1978, its relatively large companion Charon [ http://en.wikipedia.org/wiki/Charon_(moon) ] was detected by ground-based observations. This year, the Hubble [ http://hubblesite.org/newscenter/newsdesk/archive/releases/ 2005/19/ ] Space Telescope may well have detected two further members of the Pluto system [ http://www.plutoportal.net/ ]. Provisionally designated S/2005 P1 and S/2005 P2, the two potential new moons are seen orbiting in [ http://hubblesite.org/newscenter/newsdesk/archive/ releases/2005/19/image/e ] a counterclockwise direction about 44,000 kilometers (27,000 miles) from Pluto in these deep Hubble images [ http://hubblesite.org/newscenter/newsdesk/archive/releases/ 2005/19/full/ ] recorded only three days apart. The diminutive and faint companions are also apparently detected on Hubble images of Pluto from 2002, but this coming February follow-up observations are planned in an effort to confirm the discovery of the new moons. Compared to Pluto's and Charon's diameters of 2,300 and 1,300 kilometers respectively, these moons are estimated to be between 60 and 200 kilometers across. Well within the Kuiper Belt [ http://pluto.jhuapl.edu/ ], an extensive region beyond the orbit of Neptune, the Pluto system could be the first quadruple Kuiper Belt object known [ http://pluto.jhuapl.edu/science/whatWeKnow.html ]. |
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