tag:blogger.com,1999:blog-39240382100362696972023-11-16T20:17:43.091+08:00SaturnologyAn extraterrestrial photoblog about Saturn.JDsghttp://www.blogger.com/profile/04735390644321868222noreply@blogger.comBlogger391125tag:blogger.com,1999:blog-3924038210036269697.post-15326546940051979712014-10-31T00:00:00.000+08:002014-11-02T20:26:12.295+08:00Sunglint South of Titan's Kraken Mare<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjz55QlGNeAwsvF27FUNGASWYhNpabonX5PFTsn-dEVvYSaddAeQU9npLVw6pgBZ_2eBxqGSdTc34DMhcx_xGeL1BMwCUA7TN5Cae5ozl8iYDP3ztIAT-HQDSKL-UDwXpgHsqV4Ek_IGMeM/s1600/Titan+-+Sunglint+South+of+Kraken+Mare+by+Cassini+VIMS.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjz55QlGNeAwsvF27FUNGASWYhNpabonX5PFTsn-dEVvYSaddAeQU9npLVw6pgBZ_2eBxqGSdTc34DMhcx_xGeL1BMwCUA7TN5Cae5ozl8iYDP3ztIAT-HQDSKL-UDwXpgHsqV4Ek_IGMeM/s1600/Titan+-+Sunglint+South+of+Kraken+Mare+by+Cassini+VIMS.jpg" height="640" width="640" /></a></div><br />
<blockquote>This near-infrared, color mosaic from NASA's Cassini spacecraft shows the sun glinting off of Titan's north polar seas. While Cassini has captured, separately, views of the polar seas (see <a href="http://photojournal.jpl.nasa.gov/catalog/PIA17470">PIA17470</a>) and the sun glinting off of them (see <a href="http://photojournal.jpl.nasa.gov/catalog/PIA12481">PIA12481</a> and <a href="http://photojournal.jpl.nasa.gov/catalog/PIA18433">PIA18433</a>) in the past, this is the first time both have been seen together in the same view.<br />
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The sunglint, also called a specular reflection, is the bright area near the 11 o'clock position at upper left. This mirror-like reflection, known as the specular point, is in the south of Titan's largest sea, Kraken Mare, just north of an island archipelago separating two separate parts of the sea.<br />
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This particular sunglint was so bright as to saturate the detector of Cassini's Visual and Infrared Mapping Spectrometer (VIMS) instrument, which captures the view. It is also the sunglint seen with the highest observation elevation so far -- the sun was a full 40 degrees above the horizon as seen from Kraken Mare at this time -- much higher than the 22 degrees seen in <a href="http://photojournal.jpl.nasa.gov/catalog/PIA18433">PIA18433</a>. Because it was so bright, this glint was visible through the haze at much lower wavelengths than before, down to 1.3 microns.<br />
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The southern portion of Kraken Mare (the area surrounding the specular feature toward upper left) displays a "bathtub ring" -- a bright margin of evaporate deposits -- which indicates that the sea was larger at some point in the past and has become smaller due to evaporation. The deposits are material left behind after the methane & ethane liquid evaporates, somewhat akin to the saline crust on a salt flat.<br />
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The highest resolution data from this flyby -- the area seen immediately to the right of the sunglint -- cover the labyrinth of channels that connect Kraken Mare to another large sea, Ligeia Mare. Ligeia Mare itself is partially covered in its northern reaches by a bright, arrow-shaped complex of clouds. The clouds are made of liquid methane droplets, and could be actively refilling the lakes with rainfall.<br />
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The view was acquired during Cassini's August 21, 2014, flyby of Titan, also referred to as "T104" by the Cassini team.<br />
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The view contains real color information, although it is not the natural color the human eye would see. Here, red in the image corresponds to 5.0 microns, green to 2.0 microns, and blue to 1.3 microns. These wavelengths correspond to atmospheric windows through which Titan's surface is visible. The unaided human eye would see nothing but haze, as in <a href="http://photojournal.jpl.nasa.gov/catalog/PIA12528">PIA12528</a>.</blockquote><br />
<b>Image credit:</b> <a href="http://photojournal.jpl.nasa.gov/catalog/PIA18432">NASA/JPL-Caltech/University of Arizona/University of Idaho</a><br />
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<b>Note:</b> For more information, see <a href="http://photojournal.jpl.nasa.gov/catalog/PIA18433">PIA18433: Sunglint on a Hydrocarbon Lake</a> and <a href="http://www.jpl.nasa.gov/news/news.php?release=2014-378&rn=news.xml&rst=4359">Cassini Sees Sunny Seas on Titan</a>.JDsghttp://www.blogger.com/profile/04735390644321868222noreply@blogger.com0tag:blogger.com,1999:blog-3924038210036269697.post-65698997273386703442014-10-14T00:00:00.000+08:002015-01-01T20:46:14.791+08:00Tethys and the A- and F-Rings<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiEookeDR9Gil_JC7Sj9QmztI18zcT3iJwTPlt8CuP_Y_KpRZNslclE30M5w0KtM_zFUyHPGdC6Z37B6eTvj4DQRWq6YRyfRQTNwx09hJUYyTx43d7Yv13f_yH-9pB0naHgbyIQTeeA6Fmo/s1600/Tethys+and+the+A+and+F+Rings+by+Cassini.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiEookeDR9Gil_JC7Sj9QmztI18zcT3iJwTPlt8CuP_Y_KpRZNslclE30M5w0KtM_zFUyHPGdC6Z37B6eTvj4DQRWq6YRyfRQTNwx09hJUYyTx43d7Yv13f_yH-9pB0naHgbyIQTeeA6Fmo/s1600/Tethys+and+the+A+and+F+Rings+by+Cassini.jpg" height="640" width="640" /></a></div><br />
<blockquote>Like a drop of dew hanging on a leaf, Tethys appears to be stuck to the A and F rings from this perspective.<br />
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Tethys (660 miles, or 1,062 kilometers across), like the ring particles, is composed primarily of ice. The gap in the A ring through which Tethys is visible is the Keeler gap, which is kept clear by the small moon Daphnis (not visible here).<br />
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This view looks toward the Saturn-facing hemisphere of Tethys. North on Tethys is up and rotated 43 degrees to the right. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on July 14, 2014.<br />
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The view was acquired at a distance of approximately 1.1 million miles (1.8 million kilometers) from Tethys and at a Sun-Tethys-spacecraft, or phase, angle of 22 degrees. Image scale is 7 miles (11 kilometers) per pixel.</blockquote><br />
<b>Image credit:</b> <a href="http://photojournal.jpl.nasa.gov/catalog/PIA18284">NASA/JPL-Caltech/Space Science Institute</a>JDsghttp://www.blogger.com/profile/04735390644321868222noreply@blogger.com0tag:blogger.com,1999:blog-3924038210036269697.post-89465270411098628132014-10-07T00:00:00.000+08:002014-10-12T16:48:46.416+08:00Saturn's North Polar Hexagon<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgxC9u__iOavEKI8LnzMTmMwX_CFGv0hlt3ikMmRnUNmFUAEe2gogxYtAfpjdvSm-e2Qxaf5l5JAgYXLWGRSJ5mCepWM4qvIu4HqCFwSFyopb7D_PoIDwaVWT2JAphFDB2pMa4Oda0qImua/s1600/Saturn+-+North+Polar+Hexagon+04+by+Cassini.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgxC9u__iOavEKI8LnzMTmMwX_CFGv0hlt3ikMmRnUNmFUAEe2gogxYtAfpjdvSm-e2Qxaf5l5JAgYXLWGRSJ5mCepWM4qvIu4HqCFwSFyopb7D_PoIDwaVWT2JAphFDB2pMa4Oda0qImua/s1600/Saturn+-+North+Polar+Hexagon+04+by+Cassini.jpg" height="640" width="640" /></a></div><br />
<blockquote>Nature is often more complex and wonderful than it first appears. For example, although it looks like a simple hexagon, this feature surrounding Saturn's north pole is really a manifestation of a meandering polar jet stream. Scientists are still working to understand more about its origin and behavior.<br />
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For more on the hexagon, see <a href="http://photojournal.jpl.nasa.gov/catalog/PIA11682">PIA11682</a>.<br />
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This view looks toward the sunlit side of the rings from about 33 degrees above the ringplane. The image was taken in red light with the Cassini spacecraft wide-angle camera on July 24, 2013.<br />
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The view was acquired at a distance of approximately 605,000 miles (973,000 kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 19 degrees. Image scale is 36 miles (58 kilometers) per pixel.</blockquote><br />
<b>Image credit:</b> <a href="http://photojournal.jpl.nasa.gov/catalog/PIA18287">NASA/JPL-Caltech/Space Science Institute</a>JDsghttp://www.blogger.com/profile/04735390644321868222noreply@blogger.com0tag:blogger.com,1999:blog-3924038210036269697.post-67950142200543778012014-10-02T00:00:00.000+08:002014-10-03T14:39:18.847+08:00Titan's South Polar Vortex<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiNdC-2jNf0EzWJcQ-d_Xq2R8c0-2yBPHC_giabeQQKoyQxpjOPTtqwfopFcGOhD2V_V5CIjxgA4DLf9PCICYHL87phxjRRV_APCuVYQ2fuV5-rUIzsXRuJMvcezI5ZAntocm-JnjeaZEqS/s1600/Titan+-+South+Polar+Vortex+08+by+Cassini+VIMS.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiNdC-2jNf0EzWJcQ-d_Xq2R8c0-2yBPHC_giabeQQKoyQxpjOPTtqwfopFcGOhD2V_V5CIjxgA4DLf9PCICYHL87phxjRRV_APCuVYQ2fuV5-rUIzsXRuJMvcezI5ZAntocm-JnjeaZEqS/s1600/Titan+-+South+Polar+Vortex+08+by+Cassini+VIMS.jpg" height="410" width="640" /></a></div><br />
<blockquote>These two views of Saturn's moon Titan show the southern polar vortex, a huge, swirling cloud that was first observed by NASA's Cassini spacecraft in 2012.<br />
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The view at left is a spectral map of Titan obtained with the Cassini Visual and Infrared Mapping Spectrometer (VIMS) on November 29, 2012. The inset image is a natural-color close-up of the polar vortex taken by Cassini's wide-angle camera (part of the view previously released as <a href="http://photojournal.jpl.nasa.gov/catalog/PIA14925">PIA14925</a>).<br />
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Three distinct components are evident in the VIMS image, represented by different colors: the surface of Titan (orange, near center), atmospheric haze along the limb (light green, at top) and the polar vortex (blue, at lower left).<br />
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To the VIMS instrument, the spectrum of the southern polar vortex shows a remarkable difference with respect to other portions of Titan's atmosphere: a signature of frozen hydrogen cyanide molecules (HCN). This discovery has suggested to researchers that the atmosphere of Titan's southern hemisphere is cooling much faster than expected. Observing seasonal shifts like this in the moon's climate is a major goal for Cassini's current extended mission.</blockquote><br />
<b>Image credit:</b> NASA/JPL-Caltech/ASI/University of Arizona/SSI/Leiden Observatory and SRON<br />
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<b>Note:</b> For more information, see <a href="http://sci.esa.int/cassini-huygens/54718-titans-swirling-polar-cloud-is-cold-and-toxic/">Titan's Swirling Polar Cloud is Cold and Toxic</a> (ESA) and <a href="http://www.jpl.nasa.gov/news/news.php?release=2014-331&rn=news.xml&rst=4314">Swirling Cloud at Titan's Pole is Cold and Toxic</a> (JPL).JDsghttp://www.blogger.com/profile/04735390644321868222noreply@blogger.com0tag:blogger.com,1999:blog-3924038210036269697.post-20673651936430857532014-10-01T00:00:00.000+08:002014-10-05T21:12:30.432+08:00Unusual Changing Feature in Titan's Ligeia Mare<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhirisC7YVQYfV3h3TJkpoHrhBFyGTNEn_ENa9x2wqWEb40Ao3f3euDGfCd6ZvX8ncjEf8BY8etKAJXQFj3F-nwW66vSRV-CEZdO-iMod6iSaYwDR60aFibHVkhwCXFykJp9Lt9zHScEVVI/s1600/Titan+-+Unusual+Changing+Feature+in+Ligeia+Mare+by+Cassini.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhirisC7YVQYfV3h3TJkpoHrhBFyGTNEn_ENa9x2wqWEb40Ao3f3euDGfCd6ZvX8ncjEf8BY8etKAJXQFj3F-nwW66vSRV-CEZdO-iMod6iSaYwDR60aFibHVkhwCXFykJp9Lt9zHScEVVI/s1600/Titan+-+Unusual+Changing+Feature+in+Ligeia+Mare+by+Cassini.jpg" height="210" width="640" /></a></div><br />
<blockquote>These three images, created from Cassini Synthetic Aperture Radar (SAR) data, show the appearance and evolution of a mysterious feature in Ligeia Mare, one of the largest hydrocarbon seas on Saturn's moon Titan. The views, taken during three different Cassini flybys of Titan, show that this feature was not visible in earlier radar images of the same region and its appearance changed between 2013 and 2014.<br />
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In the images, the dark areas represent the sea, which is thought to be composed of mostly methane and ethane. Most of the bright areas represent land surface above or just beneath the water line. The mysterious bright feature appears off the coast below center in the middle and right images.<br />
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The mystery feature had not been seen in preceding SAR observations of the region from 2007 to 2009. After its first appearance in early July 2013, it was not visible in observations by Cassini's Visible and Infrared Mapping Spectrometer, obtained later in July and in September 2013. Low-resolution SAR images obtained in October 2013 also failed to recover the feature.<br />
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The SAR observation from Cassini's August 21, 2014 Titan flyby shows that the feature was still visible, although its appearance changed during the 11 months since it was last observed. The feature seems to have changed in size between the images from 2013 and 2014 -- doubling from about 30 square miles (about 75 square kilometers) to about 60 square miles (about 160 square kilometers). Ongoing analyses of these data may eliminate some of the explanations previously put forward, or reveal new clues as to what is happening in Titan's seas.<br />
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The Cassini radar team is investigating possible origins for the feature, including surface waves, rising bubbles, floating solids, solids that are suspended just below the surface or perhaps something more exotic. Researchers suspect that the appearance of this feature could be related to changing seasons on Titan, as summer draws near in the moon's northern hemisphere. Monitoring such changes is a major goal for Cassini's current extended mission.<br />
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The upper half of the middle image uses data from the April 26, 2007 Titan flyby. That area did not receive SAR coverage during the July 10, 2013 encounter, so the earlier data was used to fill-in the scene.</blockquote><br />
<b>Image credit:</b> <a href="http://photojournal.jpl.nasa.gov/catalog/PIA18430">NASA/JPL-Caltech/ASI/Cornell</a><br />
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JDsghttp://www.blogger.com/profile/04735390644321868222noreply@blogger.com0tag:blogger.com,1999:blog-3924038210036269697.post-61938811006728150982014-09-30T00:00:00.000+08:002014-10-05T21:07:22.389+08:00Saturn<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNJQjthxm06C456OxvuwvBSu0Whfu8i6oAmUxfXMdsNvKCoGpBUX-9oggCFNQ5OHtaAlBMa_YRhsrelLCDTna34Dw59c-8YS859i_JOjuljfc6VNmKTLCyY7aZHR2LPKA6MArj-BDkL2yU/s1600/Saturn+by+Cassini+14.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNJQjthxm06C456OxvuwvBSu0Whfu8i6oAmUxfXMdsNvKCoGpBUX-9oggCFNQ5OHtaAlBMa_YRhsrelLCDTna34Dw59c-8YS859i_JOjuljfc6VNmKTLCyY7aZHR2LPKA6MArj-BDkL2yU/s1600/Saturn+by+Cassini+14.jpg" height="640" width="640" /></a></div><br />
<blockquote>Saturn's many cloud patterns, swept along by high-speed winds, look as if they were painted on by some eager alien artist.<br />
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With no real surface features to slow them down, wind speeds on Saturn can top 1,100 mph (1,800 kph), more than four times the top speeds on Earth.<br />
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This view looks toward the sunlit side of the rings from about 29 degrees above the ringplane. The image was taken with the Cassini spacecraft wide-angle camera on April 4, 2014 using a spectral filter which preferentially admits wavelengths of near-infrared light centered at 752 nanometers.<br />
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The view was obtained at a distance of approximately 1.1 million miles (1.8 million kilometers) from Saturn. Image scale is 68 miles (109 kilometers) per pixel.</blockquote><br />
<b>Image credit:</b> <a href="http://photojournal.jpl.nasa.gov/catalog/PIA18280">NASA/JPL-Caltech/Space Science Institute</a>JDsghttp://www.blogger.com/profile/04735390644321868222noreply@blogger.com0tag:blogger.com,1999:blog-3924038210036269697.post-13638895178114748882014-09-24T00:00:00.000+08:002014-09-25T21:29:10.614+08:00Tethys, Hyperion, Prometheus, and the Rings<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjB9UheZX_tohRF_F1R5dH_Qb-m07fRxaliqP4uAKE0GbEwuCVY6H-MucJKhjgnNmmjn45k_5iX4rXCbQr_RPRQtAYhD8CURVpkbBzDe9bxaM35eIqIVd46YVLafzlxysGqclbIn_xvw-81/s1600/Tethys,+Hyperion+upper-left,+and+Prometheus+lower-left+by+Cassini.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjB9UheZX_tohRF_F1R5dH_Qb-m07fRxaliqP4uAKE0GbEwuCVY6H-MucJKhjgnNmmjn45k_5iX4rXCbQr_RPRQtAYhD8CURVpkbBzDe9bxaM35eIqIVd46YVLafzlxysGqclbIn_xvw-81/s1600/Tethys,+Hyperion+upper-left,+and+Prometheus+lower-left+by+Cassini.jpg" height="640" width="640" /></a></div><br />
<blockquote>The Cassini spacecraft captures a rare family photo of three of Saturn's moons that couldn't be more different from each other! As the largest of the three, Tethys (image center) is round and has a variety of terrains across its surface. Meanwhile, Hyperion (to the upper-left of Tethys) is the "wild one" with a chaotic spin and Prometheus (lower-left) is a tiny moon that busies itself sculpting the F ring.<br />
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To learn more about the surface of Tethys (660 miles, or 1,062 kilometers across), see <a href="http://photojournal.jpl.nasa.gov/catalog/PIA17164">PIA17164</a>. More on the chaotic spin of Hyperion (168 miles, or 270 kilometers across) can be found at <a href="http://photojournal.jpl.nasa.gov/catalog/PIA07683">PIA07683</a>. And discover more about the role of Prometheus (53 miles, or 86 kilometers across) in shaping the F ring in <a href="http://photojournal.jpl.nasa.gov/catalog/PIA12786">PIA12786</a>.<br />
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This view looks toward the sunlit side of the rings from about 1 degree above the ringplane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on July 14, 2014.<br />
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The view was acquired at a distance of approximately 1.2 million miles (1.9 million kilometers) from Tethys and at a Sun-Tethys-spacecraft, or phase, angle of 22 degrees. Image scale is 7 miles (11 kilometers) per pixel.</blockquote><br />
<b>Image credit:</b> <a href="http://photojournal.jpl.nasa.gov/catalog/PIA18283">NASA/JPL-Caltech/Space Science Institute</a>JDsghttp://www.blogger.com/profile/04735390644321868222noreply@blogger.com0tag:blogger.com,1999:blog-3924038210036269697.post-28274771941876387552014-09-23T00:00:00.000+08:002014-09-25T21:19:59.939+08:00Saturn's North Polar Hexagon<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEirC360LN8QO8A6G2HGAo1x9h_1lqKuHhFkQHQhyF1yqThFfYnWN-HHxknwzgrC356lwWYmIUX1SIO4c-6ppo7-OFQNkg3T6756dFeuuAVgDClHURHITkxGQJN-LQ_kC8y4o03TWi1so7RU/s1600/Saturn+-+North+Polar+Hexagon+01+by+Cassini.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEirC360LN8QO8A6G2HGAo1x9h_1lqKuHhFkQHQhyF1yqThFfYnWN-HHxknwzgrC356lwWYmIUX1SIO4c-6ppo7-OFQNkg3T6756dFeuuAVgDClHURHITkxGQJN-LQ_kC8y4o03TWi1so7RU/s1600/Saturn+-+North+Polar+Hexagon+01+by+Cassini.jpg" height="640" width="640" /></a></div><br />
<blockquote>The giant planet Saturn is mostly a gigantic ball of rotating gas, completely unlike our solid home planet. But Earth and Saturn do have something in common: weather, although the gas giant is home to some of the most bizarre weather in our Solar System, such as the swirling storm shown in this Cassini view.<br />
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Known as “the hexagon”, this weather feature is an intense, six-sided jet stream at Saturn’s north pole. Spanning some 30,000 km across, it hosts howling 320 km/h winds that spiral around a massive storm rotating anticlockwise at the heart of the region.<br />
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Numerous small vortices rotate in the opposite direction to the central storm and are dragged around with the jet stream, creating a terrifically turbulent region. While a hurricane on Earth may last a week or more, the hexagon has been raging for decades, and shows no signs of letting up.<br />
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This false-color image of the hexagon was made using ultraviolet, visible and infrared filters to highlight different regions.<br />
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The dark center of the image shows the large central storm and its eye, which is up to 50 times bigger than a terrestrial hurricane eye. The small vortices show up as pink-red clumps. Towards the lower right of the frame is a white-tinted oval storm that is bigger than any of the others — this is the largest of the vortices at some 3500 km across, twice the size of the largest hurricane ever recorded on Earth.<br />
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The darker blue region within the hexagon is filled with small haze particles, whereas the paler blue region is dominated by larger particles. This divide is caused by the hexagonal jet stream acting as a shepherding barrier — large particles cannot enter the hexagon from the outside.<br />
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These large particles are created when sunlight shines onto Saturn’s atmosphere, something that only started relatively recently in the northern hemisphere with the beginning of northern spring in August 2009.<br />
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Cassini will continue to track changes in the hexagon, monitoring its contents, shape and behavior as summer reaches Saturn’s northern hemisphere in 2017.<br />
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An animated version is available <a href="http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA17652">here</a>.</blockquote><br />
<b>Image credit:</b> <a href="http://www.esa.int/spaceinimages/Images/2014/09/A_cosmic_hurricane">NASA/JPL-Caltech/SSI/Hampton University</a>JDsghttp://www.blogger.com/profile/04735390644321868222noreply@blogger.com0tag:blogger.com,1999:blog-3924038210036269697.post-50489631135055998152014-09-16T00:00:00.000+08:002014-09-17T12:46:49.922+08:00Crescent Mimas<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhEqgSlKHM7IVsjUUjQ6zH3zyuMb3Jp2eWC-MUB6nap42UOYf9OeVRepUoHkT8QuH9n6qrNcBEPkjmwYkcR8FnZDUVRvihwaBierYxg6wmkHsMOIGxq2ocW_di1LkgmQExAuWGrJ5C_1mJp/s1600/Mimas+by+Cassini+03.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhEqgSlKHM7IVsjUUjQ6zH3zyuMb3Jp2eWC-MUB6nap42UOYf9OeVRepUoHkT8QuH9n6qrNcBEPkjmwYkcR8FnZDUVRvihwaBierYxg6wmkHsMOIGxq2ocW_di1LkgmQExAuWGrJ5C_1mJp/s1600/Mimas+by+Cassini+03.jpg" height="640" width="622" /></a></div><br />
<blockquote>A thin sliver of Mimas is illuminated, the long shadows showing off its many craters, indicators of the moon's violent history.<br />
<br />
The most famous evidence of a collision on Mimas (246 miles, or 396 kilometers across) is the crater Herschel that gives Mimas its Death Star-like appearance. See <a href="http://photojournal.jpl.nasa.gov/catalog/PIA12568">PIA12568</a> for more on Herschel.<br />
<br />
This view looks toward the anti-Saturn hemisphere of Mimas. North on Mimas is up and rotated 40 degrees to the right. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on May 20, 2013.<br />
<br />
The view was acquired at a distance of approximately 100,000 miles (200,000 kilometers) from Mimas and at a Sun-Mimas-spacecraft, or phase, angle of 130 degrees. Image scale is 4,000 feet (1 kilometer) per pixel.</blockquote><br />
<b>Image credit:</b> <a href="http://photojournal.jpl.nasa.gov/catalog/PIA18285">NASA/JPL-Caltech/Space Science Institute</a>JDsghttp://www.blogger.com/profile/04735390644321868222noreply@blogger.com0tag:blogger.com,1999:blog-3924038210036269697.post-85984167393309852932014-09-10T00:00:00.000+08:002014-09-10T00:00:00.721+08:00Bright Clumps in Saturn Ring Now Mysteriously Scarce<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjJR-2BPnr3uNEzEwMfS9V5WVY-aZlKkMwo2E1jzpdyea6EwdcKu-LXwKqenTjcIcfPvaxngTYJLMIKDqUa-rO2c1Np2w3vtelvacJCMGoG2pDrfnk4Y0AJ0NV8FEahCs2Aet2rqIuFJf8K/s1600/Remaining+Bright+Clumps+in+Saturn's+F-Ring+green+box+by+Cassini.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjJR-2BPnr3uNEzEwMfS9V5WVY-aZlKkMwo2E1jzpdyea6EwdcKu-LXwKqenTjcIcfPvaxngTYJLMIKDqUa-rO2c1Np2w3vtelvacJCMGoG2pDrfnk4Y0AJ0NV8FEahCs2Aet2rqIuFJf8K/s1600/Remaining+Bright+Clumps+in+Saturn's%2BF-Ring%2Bgreen%2Bbox%2Bby%2BCassini.jpg" height="640" width="640" /></a></div><br />
<blockquote><i>A map of Saturn's F ring from 2006 shows one of the few bright, extended clumps (indicated by a green box) seen during six years of observation by Cassini.</i><br />
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Compared to the age of the solar system -- about four-and-a-half billion years -- a couple of decades are next to nothing. Some planetary locales change little over many millions of years, so for scientists who study the planets, any object that evolves on such a short interval makes for a tempting target for study. And so it is with the ever-changing rings of Saturn.<br />
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Case in point: Saturn's narrow, chaotic and clumpy F ring. A recent NASA-funded study compared the F ring's appearance in six years of observations by the Cassini mission to its appearance during the Saturn flybys of NASA's Voyager mission, 30 years earlier. The study team found that, while the overall number of clumps in the F ring remained the same, the number of exceptionally bright clumps of material plummeted during that time. While the Voyagers saw two or three bright clumps in any given observation, Cassini spied only two of the features during a six-year period. What physical processes, they wondered, could cause only the brightest of these features to decline sharply?<br />
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While a variety of features in Saturn's many rings display marked changes over multiple years, the F ring seems to change on a scale of days, and even hours. Trying to work out what is responsible for the ring's tumultuous behavior is a major goal for ring scientists working on Cassini.<br />
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"Saturn's F ring looks fundamentally different from the time of Voyager to the Cassini era," said Robert French of the SETI Institute in Mountain View, California, who led the study along with SETI Principal Investigator Mark Showalter. "It makes for an irresistible mystery for us to investigate."<br />
<br />
The researchers hypothesize that the brightest clumps in the F ring are caused by repeated impacts into its core by small moonlets up to about 3 miles (5 kilometers) wide, whose paths around Saturn lie close to the ring and cross into it every orbit. They propose that the diminishing number of bright clumps results from a drop in the number of these little moonlets between the Voyager and Cassini eras.<br />
<br />
As for what might have caused the moonlets to become scarce, the team has a suspect: Saturn's moon Prometheus. The F ring encircles the planet at a special location, near a place called the Roche limit -- get any closer to Saturn than this, and tidal forces from the planet's gravity tear apart smaller bodies. "Material at this distance from Saturn can't decide whether it wants to remain as a ring or coalesce to form a moon," French said. Prometheus orbits just inside the F ring, and adds to the pandemonium by stirring up the ring particles, sometimes leading to the creation of moonlets, and sometimes leading to their destruction.<br />
<br />
Every 17 years, the orbit of Prometheus aligns with the orbit of the F ring in such a way that its influence is particularly strong. The study team thinks this periodic alignment might spur the creation of many new moonlets. The moonlets would then crash repeatedly through the F ring, like cars in a Hollywood high-speed chase, creating bright clumps as they smash across lanes of ring material. Fewer clumps would be created as time goes by, because the moonlets themselves are eventually destroyed by all the crashes.<br />
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As with any good scientific hypothesis, the researchers offer a way to test their ideas. It happens that the Voyager encounters with Saturn occurred a few years after the 1975 alignment between Prometheus and the F ring, and Cassini was present for the 2009 alignment. If the moon's periodic influence is indeed responsible for creating new moonlets, then the researchers expect that Cassini would see the F ring return to a Voyager-like number of bright clumps in the next couple of years.<br />
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"Cassini's continued presence at Saturn gives us an interesting opportunity to test this prediction," said Linda Spilker, Cassini project scientist at NASA's Jet Propulsion Laboratory in Pasadena, California, who was not involved in the study. "Whatever the result, we're certain to learn something valuable about how rings, as well as planets and moons, form and evolve."<br />
<br />
The study by French and colleagues was published in the online edition of the Journal <i>Icarus</i> on July 15, 2014.</blockquote><br />
<b>Image credit:</b> <a href="http://www.jpl.nasa.gov/news/news.php?release=2014-302&rn=news.xml&rst=4279">NASA/JPL-Caltech/SSI</a>JDsghttp://www.blogger.com/profile/04735390644321868222noreply@blogger.com0tag:blogger.com,1999:blog-3924038210036269697.post-36714713766850442512014-09-09T00:00:00.000+08:002014-09-09T05:18:27.622+08:00Pan in the Encke Gap<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjBffBbEK-QdjS89JdsqMXfS4dPYVoeVSt25itqLNFM1Y_HPAvxzE6gfVxQIcquJkFDyvVAvqF1K2Icea-uKb5aWezNXgf5TGU0xPdq8OOg99cHaPpO-snwUiRca_Mtb8-swtYgNlOCaRjT/s1600/Pan+in+the+Encke+Gap+by+Cassini+05.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjBffBbEK-QdjS89JdsqMXfS4dPYVoeVSt25itqLNFM1Y_HPAvxzE6gfVxQIcquJkFDyvVAvqF1K2Icea-uKb5aWezNXgf5TGU0xPdq8OOg99cHaPpO-snwUiRca_Mtb8-swtYgNlOCaRjT/s1600/Pan+in+the+Encke+Gap+by+Cassini+05.jpg" height="640" width="640" /></a></div><br />
<blockquote>Saturn's innermost moon Pan orbits the giant planet seemingly alone in a ring gap its own gravity creates.<br />
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Pan (17 miles, or 28 kilometers across) maintains the Encke Gap in Saturn's A ring by gravitationally nudging the ring particles back into the rings when they stray in the gap. Scientists think similar processes might be at work as forming planets clear gaps in the circumstellar disks from which they form.<br />
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This view looks toward the sunlit side of the rings from about 38 degrees above the ringplane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on May 3, 2014.<br />
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The view was acquired at a distance of approximately 2 million miles (3.2 million kilometers) from Pan and at a Sun-Pan-spacecraft, or phase, angle of 56 degrees. Image scale is 12 miles (19 kilometers) per pixel.</blockquote><br />
<b>Image credit:</b> <a href="http://photojournal.jpl.nasa.gov/catalog/PIA18281">NASA/JPL-Caltech/Space Science Institute</a>JDsghttp://www.blogger.com/profile/04735390644321868222noreply@blogger.com0tag:blogger.com,1999:blog-3924038210036269697.post-2965065007540095672014-09-03T00:00:00.000+08:002014-09-03T11:50:54.046+08:00Mimas and Ring Shadow<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhxvXAQu4b0HSWKk7Vwx3uNmcSAkka8Ekvn2n9U7zM0C3LrApdjBKnoKQ7KiYASQx7KrSCsHaxNW2Fv3HHt8oPpw2vUTFWLRlu5uVxa5kDOPRPx8VNoYVAzEBzbPZEjzlC2sPwaxdTDpVXB/s1600/Mimas+and+Ring+Shadow+by+Cassini.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhxvXAQu4b0HSWKk7Vwx3uNmcSAkka8Ekvn2n9U7zM0C3LrApdjBKnoKQ7KiYASQx7KrSCsHaxNW2Fv3HHt8oPpw2vUTFWLRlu5uVxa5kDOPRPx8VNoYVAzEBzbPZEjzlC2sPwaxdTDpVXB/s1600/Mimas+and+Ring+Shadow+by+Cassini.jpg" height="640" width="640" /></a></div><br />
<blockquote>As if trying to get our attention, Mimas is positioned against the shadow of Saturn's rings, bright on dark. As we near summer in Saturn's northern hemisphere, the rings cast ever larger shadows on the planet.<br />
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With a reflectivity of about 96 percent, Mimas (246 miles, or 396 kilometers across) appears bright against the less-reflective Saturn.<br />
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This view looks toward the sunlit side of the rings from about 10 degrees above the ringplane. The image was taken with the Cassini spacecraft wide-angle camera on July 13, 2014 using a spectral filter which preferentially admits wavelengths of near-infrared light centered at 752 nanometers.<br />
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The view was acquired at a distance of approximately 1.1 million miles (1.8 million kilometers) from Saturn and approximately 1 million miles (1.6 million kilometers) from Mimas. Image scale is 67 miles (108 kilometers) per pixel at Saturn and 60 miles (97 kilometers) per pixel at Mimas.</blockquote><br />
<b>Image credit:</b> <a href="http://photojournal.jpl.nasa.gov/catalog/PIA18282">NASA/JPL-Caltech/Space Science Institute</a>JDsghttp://www.blogger.com/profile/04735390644321868222noreply@blogger.com0tag:blogger.com,1999:blog-3924038210036269697.post-1592486308046959902014-09-02T00:00:00.000+08:002014-09-04T13:52:27.625+08:00Titan's Subsurface Reservoirs<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj7_iDkdxW4YyLvratQ0nE6jFGbEzX1smeEghM3h0hZZ7wh8Ixw8x33h5w83WC_URJRBN3lb8w8_fNh_NE5eIBThfPtJoK9he_O7H3u0FsvhNjli2eVmIGlyNZOCoukYMGAC9p1YTexP0xi/s1600/Titan's+Subsurface+Reservoirs.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj7_iDkdxW4YyLvratQ0nE6jFGbEzX1smeEghM3h0hZZ7wh8Ixw8x33h5w83WC_URJRBN3lb8w8_fNh_NE5eIBThfPtJoK9he_O7H3u0FsvhNjli2eVmIGlyNZOCoukYMGAC9p1YTexP0xi/s1600/Titan's%2BSubsurface%2BReservoirs.jpg" height="362" width="640" /></a></div><br />
<blockquote>Hundreds of lakes and seas are spread across the surface of Saturn's moon Titan. These lakes are filled with hydrocarbons, a form of organic compound that is also found naturally on Earth and includes methane.<br />
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While most of the liquid in the lakes is thought to be replenished by rainfall from clouds in Titan's atmosphere, the cycling of liquid between the subsurface, surface and atmosphere is still not well understood.<br />
<br />
Scientists have modeled how a subsurface reservoir ('alkanofer') of liquid hydrocarbons, filled with rainfall runoff, would diffuse throughout Titan's porous icy crust. They found that this diffusion could cause a new reservoir – formed from clathrates - to form where the bottom of the original reservoir meets layers of non-porous ice.<br />
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Clathrates are compounds that form a crystal structure with small cages that trap other substances like methane and ethane. Titan's subsurface clathrate reservoirs would interact with and fractionate (separate) the liquid phase within the original underground hydrocarbon lake, slowly changing its composition. Eventually, subsurface lakes that had come into contact with the clathrate layer would mainly be composed of either propane or ethane, depending on the type of clathrate that had formed.<br />
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Importantly, this would continue up to Titan's surface. Lakes fed by these propane or ethane subsurface reservoirs would show the same kind of composition, whereas those fed by rainfall would be different and contain methane, nitrogen, and trace amounts of argon and carbon monoxide. The composition of the lake would indicate what was happening deep underground.</blockquote><br />
<b>Illustration credit:</b> <a href="http://sci.esa.int/cassini-huygens/54587-titans-subsurface-reservoirs/">ESA/ATG medialab</a><br />
<br />
Note: For more information, see <a href="http://photojournal.jpl.nasa.gov/catalog/PIA18417">PIA18417: Titan's Subsurface Reservoirs (Artist's Concept)</a> and <a href="http://www.jpl.nasa.gov/news/news.php?release=2014-294&rn=news.xml&rst=4278">Icy Aquifers on Titan Transform Methane Rainfall</a>.JDsghttp://www.blogger.com/profile/04735390644321868222noreply@blogger.com0tag:blogger.com,1999:blog-3924038210036269697.post-68590538491794237722014-08-26T00:00:00.000+08:002014-08-26T21:08:12.472+08:00Two Ringlets in the Encke Gap<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhbRvrTNyT5XtEja8nVAgt_HW3lqCWE6K2Rulpm2GkFJxgxaRqy7RdpvDOnlPpu89LlQTVMzTZD89cD5shgeLrXTcXGrb28ZM6LOCfVVfRPO8d3eQfWBIuNtc4yDgsucMECEFiNbBF3sCA3/s1600/Two+Ringlets+in+the+Encke+Gap+by+Cassini.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhbRvrTNyT5XtEja8nVAgt_HW3lqCWE6K2Rulpm2GkFJxgxaRqy7RdpvDOnlPpu89LlQTVMzTZD89cD5shgeLrXTcXGrb28ZM6LOCfVVfRPO8d3eQfWBIuNtc4yDgsucMECEFiNbBF3sCA3/s640/Two+Ringlets+in+the+Encke+Gap+by+Cassini.jpg" height="640" width="640" /></a></div><br />
<blockquote>Although it appears empty from a distance, the Encke gap in Saturn's A ring has three ringlets threaded through it, two of which are visible here.<br />
<br />
Each ringlet has dynamical structure such as the clumps seen in this image. The clumps move about and even appear and disappear, in part due to the gravitational effects of Pan.<br />
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This view looks toward the sunlit side of the rings from about 27 degrees above the ringplane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on May 11, 2013.<br />
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The view was obtained at a distance of approximately 199,000 miles (321,000 kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 121 degrees. Image scale is 1 mile (2 kilometers) per pixel.</blockquote><br />
<b>Image credit:</b> <a href="http://photojournal.jpl.nasa.gov/catalog/PIA18277">NASA/JPL-Caltech/Space Science Institute</a>JDsghttp://www.blogger.com/profile/04735390644321868222noreply@blogger.com0tag:blogger.com,1999:blog-3924038210036269697.post-61851768781656106752014-08-19T00:00:00.000+08:002014-08-23T20:19:33.352+08:00Saturn From Above<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj9yFnKXBbksQd7T6bjN5IIqDwIZoVIZXJVj0ob3Jh-eyCIV6SBN2TEhFCQ936Ne_q20HrUFpA1WMSG3sWZJcv4v9chE0tYThH6Ov2X04Y_Iu2mOJ6By5ESCxGD59e21fMA0Qi9cP909EPe/s1600/Saturn+by+Cassini+12.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj9yFnKXBbksQd7T6bjN5IIqDwIZoVIZXJVj0ob3Jh-eyCIV6SBN2TEhFCQ936Ne_q20HrUFpA1WMSG3sWZJcv4v9chE0tYThH6Ov2X04Y_Iu2mOJ6By5ESCxGD59e21fMA0Qi9cP909EPe/s1600/Saturn+by+Cassini+12.jpg" height="640" width="640" /></a></div><br />
<blockquote>Saturn reigns supreme, encircled by its retinue of rings.<br />
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Although all four giant planets have ring systems, Saturn's is by far the most massive and impressive. Scientists are trying to understand why by studying how the rings have formed and how they have evolved over time.<br />
<br />
Also seen in this image is Saturn's famous north polar vortex and hexagon.<br />
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This view looks toward the sunlit side of the rings from about 37 degrees above the ringplane. The image was taken with the Cassini spacecraft wide-angle camera on May 4, 2014 using a spectral filter which preferentially admits wavelengths of near-infrared light centered at 752 nanometers.<br />
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The view was acquired at a distance of approximately 2 million miles (3 million kilometers) from Saturn. Image scale is 110 miles (180 kilometers) per pixel.</blockquote><br />
<b>Image credit:</b> <a href="http://photojournal.jpl.nasa.gov/catalog/PIA18278">NASA/JPL-Caltech/Space Science Institute</a><br />
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<b>Note:</b> For more information, see <a href="http://www.esa.int/spaceinimages/Images/2014/08/Supreme_Saturn">Supreme Saturn</a>.JDsghttp://www.blogger.com/profile/04735390644321868222noreply@blogger.com0tag:blogger.com,1999:blog-3924038210036269697.post-32084106138280237752014-08-14T00:00:00.000+08:002014-08-14T00:00:00.573+08:00Methane Clouds Over Titan's Ligeia Mare<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiy6K6dLk8-HYJiuCMK360Dsl52ittiIXTY7Uf4U9Q7jzQzU_6uy_vmQR5VgQDVMQ2gVoc5dV9zEauDm2SXQKcvNZQuyUn-1gK2UrPaaYRrYXfu0366E9GYTdquSg5F-RpC5UT8zw3CQVOC/s1600/Titan+-+Methane+Clouds+over+Ligeia+Mare+03+by+Cassini.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiy6K6dLk8-HYJiuCMK360Dsl52ittiIXTY7Uf4U9Q7jzQzU_6uy_vmQR5VgQDVMQ2gVoc5dV9zEauDm2SXQKcvNZQuyUn-1gK2UrPaaYRrYXfu0366E9GYTdquSg5F-RpC5UT8zw3CQVOC/s1600/Titan+-+Methane+Clouds+over+Ligeia+Mare+03+by+Cassini.jpg" height="640" width="640" /></a></div><br />
<blockquote>This animated sequence of Cassini images shows methane clouds moving above the large methane sea on Saturn's moon Titan known as Ligeia Mare.<br />
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The spacecraft captured the views between July 20 and July 22, 2014, as it departed Titan following a flyby. Cassini tracked the system of clouds as it developed and dissipated over Ligeia Mare during this two-day period. Measurements of the cloud motions indicate wind speeds of around 7 to 10 miles per hour (3 to 4.5 meters per second).<br />
<br />
The timing between exposures in the sequence varies. In particular, there is a 17.5-hour jump between the second and third frames. Most other frames are separated by one to two hours.<br />
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A separate view, <a href="http://photojournal.jpl.nasa.gov/catalog/PIA18421">PIA18421</a>, shows the location of these clouds relative to features in Titan's north polar region.</blockquote><br />
<b>Animation credit:</b> <a href="http://photojournal.jpl.nasa.gov/catalog/PIA18420">NASA/JPL-Caltech/Space Science Institute</a><br />
<br />
<b>Note:</b> For more information, see <a href="http://www.jpl.nasa.gov/news/news.php?release=2014-274&rn=news.xml&rst=4256">Cassini Tracks Clouds Developing Over a Titan Sea</a>.JDsghttp://www.blogger.com/profile/04735390644321868222noreply@blogger.com0tag:blogger.com,1999:blog-3924038210036269697.post-71779327930780040572014-08-13T00:00:00.000+08:002014-08-13T05:21:20.122+08:00Rhea and Epimetheus<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgtgD-1bjoeujVSXktBn1GsjyKqg9QJQN3YujAqbKFkuTvieb9aU-wrM0rrcpyMDEVGxqzMX4a-ayq_9AhwMmgFTXQhgPv-9Vv15LPmBarl0ZQlRIgF24lvXolv2PPFsifyKXz5TS20SrwN/s1600/Rhea+and+Epimetheus+01+by+Cassini.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgtgD-1bjoeujVSXktBn1GsjyKqg9QJQN3YujAqbKFkuTvieb9aU-wrM0rrcpyMDEVGxqzMX4a-ayq_9AhwMmgFTXQhgPv-9Vv15LPmBarl0ZQlRIgF24lvXolv2PPFsifyKXz5TS20SrwN/s1600/Rhea+and+Epimetheus+01+by+Cassini.png" height="640" width="546" /></a></div><br />
<blockquote>Saturn has a great many more moons than our planet – a whopping 62. A single moon, Titan, accounts for an overwhelming 96% of all the material orbit the planet, with a group of six other smaller moons dominating the rest. The other 55 small satellites whizzing around Saturn make up the tiny remainder along with the gas giant’s famous rings.<br />
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One of the subjects of this Cassini image, Rhea, belongs to that group of six. Set against a backdrop showing Saturn and its intricate system of icy rings, Rhea dominates the scene and dwarfs its tiny companion, one of the 55 small satellites known as Epimetheus. <br />
<br />
Although they appear to be close to one another, this is a trick of perspective – this view was obtained when Cassini was some 1.2 million km from Rhea, and 1.6 million km from Epimetheus, meaning the moons themselves had a hefty separation of 400,000 km.<br />
<br />
However, even if they were nearer to each other, Rhea would still loom large over Epimetheus: at 1528 km across and just under half the size of our own Moon, Rhea is well over 10 times the size of Epimetheus, which is a modest 113 km across.<br />
<br />
As is traditional for the earliest discovered moons of Saturn, both are named after figures from Greek mythology: the Titan Rhea (“mother of the gods”) and Prometheus’ brother Epimetheus (“after thinker” or “hindsight”). <br />
<br />
This image was taken by Cassini’s narrow-angle camera on 24 March 2010. A monochrome version was previously released by NASA as <a href="http://photojournal.jpl.nasa.gov/catalog/PIA12638">PIA12638: Big and Small Before Rings</a>.</blockquote><br />
<b>Image credit: Image data credit:</b> <a href="http://www.esa.int/spaceinimages/Images/2014/08/Saturn_s_moon_Rhea_Epimetheus_transiting">NASA/JPL-Caltech/Space Science Institute</a>; <b>Processed image copyright:</b> G. UgarkovićJDsghttp://www.blogger.com/profile/04735390644321868222noreply@blogger.com0tag:blogger.com,1999:blog-3924038210036269697.post-91493425104603915072014-08-12T00:00:00.000+08:002014-08-16T20:41:21.663+08:00Pandora and the Rings<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjNRVAJdzViZldSrwJPk7Yo8_mmgCw5fVkPIkjDipQ5QJT9OKgWrp3JJ9OTg9x0YbsdfEGZAj6QuhVYG47H5QCoBWwhwIvi-W1EawsLl1MB6bXPJPAatAcqD9F5jf-mjO-ON9r5_6Igfzer/s1600/Pandora+by+Cassini+04.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjNRVAJdzViZldSrwJPk7Yo8_mmgCw5fVkPIkjDipQ5QJT9OKgWrp3JJ9OTg9x0YbsdfEGZAj6QuhVYG47H5QCoBWwhwIvi-W1EawsLl1MB6bXPJPAatAcqD9F5jf-mjO-ON9r5_6Igfzer/s1600/Pandora+by+Cassini+04.jpg" height="640" width="612" /></a></div><br />
<blockquote>The F ring shepherd Pandora is captured here along with other well-known examples of how Saturn’s moons shape the rings. From the narrow F ring, to the gaps in the A ring, to the Cassini Division, Saturn's rings are a masterpiece of gravitational sculpting by the moons.<br />
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Pandora (50 miles, or 81 kilometers across), along with its fellow shepherd Prometheus (53 miles, or 86 kilometers across), helps confine the F ring and keep it from spreading.<br />
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This view looks toward the unilluminated side of the rings from about 31 degrees below the ringplane. The image was taken in visible light with the Cassini spacecraft wide-angle camera on March 8, 2014.<br />
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The view was obtained at a distance of approximately 533,000 miles (858,000 kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 63 degrees. Image scale is 32 miles (51 kilometers) per pixel.</blockquote><br />
<b>Image credit:</b> <a href="http://photojournal.jpl.nasa.gov/catalog/PIA18271">NASA/JPL-Caltech/Space Science Institute</a><br />
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<b>Note:</b> For more information, see <a href="http://www.esa.int/spaceinimages/Images/2014/08/Shepherd_and_Flock">Shepherd and Flock</a>.JDsghttp://www.blogger.com/profile/04735390644321868222noreply@blogger.com0tag:blogger.com,1999:blog-3924038210036269697.post-68091040499151944912014-08-05T00:00:00.000+08:002014-08-05T05:13:41.864+08:00Saturn's North Polar Vortex<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgWnJebVsBugYfeMY-cVKkN3cO56X0Knwhyphenhyphen0cOgk0LQsKlSq0dVr2Po4XRd1iYmPAyUFa0TkNX6j8AjWuXRB7Z_raoYHugN5qiCfWVEF5-OdxdeFr14gX-yV99vjuZNmzNG8ziDLzcDxN1X/s1600/Saturn+-+North+Pole+Hurricane+06+Infrared+by+Cassini.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgWnJebVsBugYfeMY-cVKkN3cO56X0Knwhyphenhyphen0cOgk0LQsKlSq0dVr2Po4XRd1iYmPAyUFa0TkNX6j8AjWuXRB7Z_raoYHugN5qiCfWVEF5-OdxdeFr14gX-yV99vjuZNmzNG8ziDLzcDxN1X/s1600/Saturn+-+North+Pole+Hurricane+06+Infrared+by+Cassini.jpg" height="640" width="640" /></a></div><br />
<blockquote>Like a giant eye for the giant planet, Saturn's great vortex at its north pole appears to stare back at Cassini as Cassini stares at it.<br />
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Measurements have sized the "eye" at a staggering 1,240 miles (2,000 kilometers) across with cloud speeds as fast as 330 miles per hour (150 meters per second). For color views of the eye and the surrounding region, see <a href="http://photojournal.jpl.nasa.gov/catalog/PIA14946">PIA14946</a> and <a href="http://photojournal.jpl.nasa.gov/catalog/PIA14944">PIA14944</a>.<br />
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The image was taken with the Cassini spacecraft narrow-angle camera on April 2, 2014 using a combination of spectral filters which preferentially admit wavelengths of near-infrared light centered at 748 nanometers.<br />
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The view was obtained at a distance of approximately 1.4 million miles (2.2 million kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 43 degrees. Image scale is 8 miles (13 kilometers) per pixel.</blockquote><br />
<b>Image credit:</b> <a href="http://photojournal.jpl.nasa.gov/catalog/PIA18273">NASA/JPL-Caltech/Space Science Institute</a>JDsghttp://www.blogger.com/profile/04735390644321868222noreply@blogger.com0tag:blogger.com,1999:blog-3924038210036269697.post-45677704303715636452014-07-31T00:00:00.000+08:002014-08-02T18:09:49.630+08:00Elevated View of Enceladus' South Pole<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiFGFh5uvKVgO4WiLIYjUomWjvhaUQZCCxRv5QONklCwW_N6_TvHA9syUobaMMRc9NPUfT8g0x4Bmn7KHSyTNzybNl5ijAEN-4l-V4rx6cE2xAlRslIhgoJQ5p3RIIhjBwScG5haZQ1SRR8/s1600/Enceladus+-+Elevated+View+of+South+Pole+01+by+Cassini.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiFGFh5uvKVgO4WiLIYjUomWjvhaUQZCCxRv5QONklCwW_N6_TvHA9syUobaMMRc9NPUfT8g0x4Bmn7KHSyTNzybNl5ijAEN-4l-V4rx6cE2xAlRslIhgoJQ5p3RIIhjBwScG5haZQ1SRR8/s1600/Enceladus+-+Elevated+View+of+South+Pole+01+by+Cassini.jpg" height="640" width="640" /></a></div><br />
<blockquote>This dramatic view looks across the region of Enceladus' geyser basin and down on the ends of the Baghdad and Damascus fractures that face Saturn. The image, which looks approximately in the direction of Saturn, was taken from a more elevated viewpoint than other Cassini survey images of this area of the moon's south pole.<br />
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The geysering segments of the fractures seen here are among the most active and warmest in the whole region. As seen from the spacecraft from an elevation angle of 25 degrees south, the jets are projected against the bright surface as opposed to black sky. Consequently, despite the pronounced activity, the jets appear fuzzy, or indistinct, in this image and their tilts are consequently not measurable. Though their source locations are clearly seen, this image was not used in the process of triangulation, but instead it was used to confirm source locations determined from triangulation using other images.<br />
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The image was taken with Cassini's narrow-angle camera through the clear filter on August 13, 2010, with an image scale about 230 feet (70 meters) per pixel and a Sun-Enceladus-spacecraft, or phase, angle of about 151 degrees.<br />
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This image was one of those used to confirm the sources of Enceladus' geysers as described in a paper by Porco, DiNino, and Nimmo, and published in the online version of the <i>Astronomical Journal</i> in July 2014: <a href="http://dx.doi.org/10.1088/0004-6256/148/3/45">http://dx.doi.org/10.1088/0004-6256/148/3/45</a>.<br />
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A companion paper, by Nimmo et al. is available at: <a href="http://dx.doi.org/10.1088/0004-6256/148/3/46">http://dx.doi.org/10.1088/0004-6256/148/3/46</a>.</blockquote><br />
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgwPP0wXElaofJ12TV9X8tfoNXmoWTfuDiz5H5wsxbmXVnBCIDKPUulhnwG5vHLyXn6xjBGT6bcs8tV49jZ7WW-50Y5tYqTjurw6Vdee3g23YKQgLqVc48Mb07NoG3z_N-YsoP9f5033aeB/s1600/Enceladus+-+Elevated+View+of+South+Pole+02+by+Cassini.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgwPP0wXElaofJ12TV9X8tfoNXmoWTfuDiz5H5wsxbmXVnBCIDKPUulhnwG5vHLyXn6xjBGT6bcs8tV49jZ7WW-50Y5tYqTjurw6Vdee3g23YKQgLqVc48Mb07NoG3z_N-YsoP9f5033aeB/s1600/Enceladus+-+Elevated+View+of+South+Pole+02+by+Cassini.jpg" height="640" width="640" /></a></div><br />
<b>Image credit:</b> NASA/JPL-Caltech/Space Science Institute<br />
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<b>Note:</b> For more information, see <a href="http://photojournal.jpl.nasa.gov/catalog/PIA17186">PIA17186: Geyser Basin in 3-D</a>, <a href="http://photojournal.jpl.nasa.gov/catalog/PIA17187">PIA17187: Enceladus' Plume Brightness Variations</a>, <a href="http://photojournal.jpl.nasa.gov/catalog/PIA17188">PIA17188: Surveyor's Map of Enceladus' Geyser Basin</a>, <a href="http://photojournal.jpl.nasa.gov/catalog/PIA17189">PIA17189: What Lies Beneath: Close Up View (Artist's Concept)</a>, <a href="http://photojournal.jpl.nasa.gov/catalog/PIA17190">PIA17190: What Lies Beneath: Regional View (Artist's Concept)</a>, and <a href="http://www.jpl.nasa.gov/news/news.php?release=2014-246&rn=news.xml&rst=4231">Cassini Spacecraft Reveals 101 Geysers and More on Icy Saturn Moon</a>.JDsghttp://www.blogger.com/profile/04735390644321868222noreply@blogger.com0tag:blogger.com,1999:blog-3924038210036269697.post-32946043665967552342014-07-30T00:00:00.000+08:002014-08-03T07:04:09.085+08:00Enceladus Geysers<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHQuY48H85V2GWAk0UB0UGspgMAO0wORvH-4ZZklfmZqBUyjKgbg3y1Sfw73PlHi-lC25vqmPXQKlHDFnuhCIA6xhC7df_GJz-JLkkTn1bt9cY1GHAgopztEH0A-A0vb0g5rcTp26dd5Lu/s1600/Enceladus+-+Plumes+02+by+Cassini.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHQuY48H85V2GWAk0UB0UGspgMAO0wORvH-4ZZklfmZqBUyjKgbg3y1Sfw73PlHi-lC25vqmPXQKlHDFnuhCIA6xhC7df_GJz-JLkkTn1bt9cY1GHAgopztEH0A-A0vb0g5rcTp26dd5Lu/s1600/Enceladus+-+Plumes+02+by+Cassini.jpg" height="372" width="640" /></a></div><br />
<blockquote>This Cassini narrow-angle camera image -- one of those acquired in the survey conducted by the Cassini imaging science team of the geyser basin at the south pole of Enceladus -- was taken as Cassini was looking across the moon's south pole. At the time, the spacecraft was essentially in the moon's equatorial plane. The image scale is 1280 feet (390 meters) per pixel and the sun-Enceladus-spacecraft, or phase, angle is 162.5 degrees.<br />
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The image was taken through the clear filter of the narrow angle camera on November 30, 2010, 1.4 years after southern autumnal equinox. The shadow of the body of Enceladus on the lower portions of the jets is clearly seen.<br />
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In an <a href="http://photojournal.jpl.nasa.gov/figures/PIA17184_fig1.jpg">annotated version of the image</a>, the colored lines represent the projection of Enceladus' shadow on a plane normal to the branch of the Cairo fracture (yellow line), normal to the Baghdad fracture (blue line) and normal to the Damascus fracture (pink line).<br />
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Post-equinox images like this, clearly showing the different projected locations of the intersection between the shadow and the curtain of jets from each fracture, were useful for scientists in checking the triangulated positions of the geysers, as described in a paper by Porco, DiNino, and Nimmo, and published in the online version of the <i>Astronomical Journal</i> in July 2014: <a href="http://dx.doi.org/10.1088/0004-6256/148/3/45">http://dx.doi.org/10.1088/0004-6256/148/3/45</a>.<br />
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A companion paper, by Nimmo et al. is available at: <a href="http://dx.doi.org/10.1088/0004-6256/148/3/46">http://dx.doi.org/10.1088/0004-6256/148/3/46</a>.</blockquote><br />
<b>Image credit:</b> <a href="http://photojournal.jpl.nasa.gov/catalog/PIA17184">NASA/JPL-Caltech/Space Science Institute</a><br />
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<b>Note:</b> For more information, see <a href="http://science.nasa.gov/science-news/science-at-nasa/2014/27jul_101geysers/">101 Geysers on Icy Saturn Moon</a>.JDsghttp://www.blogger.com/profile/04735390644321868222noreply@blogger.com0tag:blogger.com,1999:blog-3924038210036269697.post-7570617628289049002014-07-29T00:00:00.000+08:002014-07-30T20:56:31.315+08:00Tethys<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgiEE4FpSHEnTXhyphenhyphenbOMRfpy0STMqE-oPujGMUb8KA6z-2du-Gnw7pJDCl_5435U9Mj13WCqlOa_45zVHmTYP2aw8K4mLWBQBYfkqxDyD0L7XzPJPhjzru-GwR4FCzBF_n2N092_ibe1upwV/s1600/Tethys+by+Cassini+08.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgiEE4FpSHEnTXhyphenhyphenbOMRfpy0STMqE-oPujGMUb8KA6z-2du-Gnw7pJDCl_5435U9Mj13WCqlOa_45zVHmTYP2aw8K4mLWBQBYfkqxDyD0L7XzPJPhjzru-GwR4FCzBF_n2N092_ibe1upwV/s1600/Tethys+by+Cassini+08.jpg" height="640" width="616" /></a></div><br />
<blockquote>Tethys, like many moons in the solar system, keeps one face pointed towards the planet around which it orbits. Tethys' anti-Saturn face is seen here, fully illuminated, basking in sunlight. On the right side of the moon in this image is the huge crater Odysseus.<br />
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The Odysseus crater is 280 miles (450 kilometers) across while Tethys is 660 miles (1,062 kilometers) across. See <a href="http://photojournal.jpl.nasa.gov/catalog/PIA07693">PIA07693</a> for a closer view and more information on the Odysseus crater.<br />
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This view looks toward the anti-Saturn side of Tethys. North on Tethys is up and rotated 33 degrees to the right. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on June 15, 2013.<br />
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The view was acquired at a distance of approximately 503,000 miles (809,000 kilometers) from Tethys. Image scale is 3 miles (5 kilometers) per pixel.</blockquote><br />
<b>Image credit:</b> <a href="http://photojournal.jpl.nasa.gov/catalog/PIA18275">NASA/JPL-Caltech/Space Science Institute</a>JDsghttp://www.blogger.com/profile/04735390644321868222noreply@blogger.com0tag:blogger.com,1999:blog-3924038210036269697.post-125474502385318072014-07-22T00:00:00.000+08:002014-07-22T19:53:15.692+08:00Crescent Saturn<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgmgHqIfg_GW7X0XjVaxOLHGfp_smmEz70hUDR2_1teTB4EzwqSQgx2xGczc3eHhQtYlVDug-Qxdz30ul2Q1QPQuwI_m0PXprT3zD2idy0u_usHhyeuNPZoOHEYCf4rjDgNCTTDgJV34lEU/s1600/Saturn+by+Cassini+11.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgmgHqIfg_GW7X0XjVaxOLHGfp_smmEz70hUDR2_1teTB4EzwqSQgx2xGczc3eHhQtYlVDug-Qxdz30ul2Q1QPQuwI_m0PXprT3zD2idy0u_usHhyeuNPZoOHEYCf4rjDgNCTTDgJV34lEU/s1600/Saturn+by+Cassini+11.jpg" height="640" width="640" /></a></div>
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<blockquote>
Saturn appears to Cassini's cameras as a thin, sunlit crescent in this unearthly view. Citizens of Earth, being so much closer to the Sun than Saturn, never get to enjoy a view of Saturn like this without the aid of our robot envoys.<br />
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Parts of the night side of Saturn show faint illumination due to light reflected off the rings back onto the planet, an effect dubbed "ringshine." This view looks toward the unilluminated side of the rings from about 43 degrees below the ringplane. The image was taken in green light with the Cassini spacecraft wide-angle camera on August 4, 2013.<br />
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The view was obtained at a distance of approximately 1.2 million miles (2 million kilometers) from Saturn. Image scale is 75 miles (120 kilometers) per pixel.</blockquote>
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<b>Image credit:</b> <a href="http://photojournal.jpl.nasa.gov/catalog/PIA18276">NASA/JPL-Caltech/Space Science Institute</a>JDsghttp://www.blogger.com/profile/04735390644321868222noreply@blogger.com0tag:blogger.com,1999:blog-3924038210036269697.post-4103779212088412372014-07-15T00:00:00.000+08:002014-07-17T13:36:24.868+08:00Prometheus and the Rings<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiPxXahflqxeSsfd8wISAuAjFPmuUSMRShsg6Bt3q_eDkBWxiIfTl4RIZ6MlqzMem26iET6qgKWrai-jNKAUD3jmvxzO2lHN_qC_AMcUZwQ5alCMM084Re7PUaXrwb8Z4JIiJDK16nsDKdh/s1600/Prometheus+and+the+Rings+04+by+Cassini.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiPxXahflqxeSsfd8wISAuAjFPmuUSMRShsg6Bt3q_eDkBWxiIfTl4RIZ6MlqzMem26iET6qgKWrai-jNKAUD3jmvxzO2lHN_qC_AMcUZwQ5alCMM084Re7PUaXrwb8Z4JIiJDK16nsDKdh/s1600/Prometheus+and+the+Rings+04+by+Cassini.jpg" height="634" width="640" /></a></div><br />
<blockquote>Seen within the vast expanse of Saturn's rings, Prometheus appears as little more than a dot. But that little moon still manages to shape the F ring, confining it to its narrow domain.<br />
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Prometheus (53 miles, or 86 kilometers across) and its fellow moon Pandora (50 miles, or 81 kilometers across) orbit beside the F ring and keep the ring from spreading outward through a process dubbed "shepherding."<br />
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This view looks toward the unilluminated side of the rings from about 45 degrees below the ringplane. The image was taken in green light with the Cassini spacecraft wide-angle camera on March 8, 2014.<br />
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The view was obtained at a distance of approximately 533,000 miles (858,000 kilometers) from Prometheus and at a Sun-Prometheus-spacecraft, or phase, angle of 90 degrees. Image scale is 32 miles (51 kilometers) per pixel.</blockquote><br />
<b>Image credit:</b> <a href="http://photojournal.jpl.nasa.gov/catalog/PIA18272">NASA/JPL-Caltech/Space Science Institute</a>JDsghttp://www.blogger.com/profile/04735390644321868222noreply@blogger.com0tag:blogger.com,1999:blog-3924038210036269697.post-22649554584590100842014-07-08T00:00:00.000+08:002014-07-08T11:52:09.382+08:00Saturn's North Polar Vortex and Rings<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgA1r51dc76KiUjd_IljOj5W88AvrJSbgNcvxPa7mNa_xXz_nNr852YKwClz2Y_8noom56NDT4sONLrGp1ou1K1XcCumNI7Nd1oqDy0wG1pc6ujtt1wSbb3RrSmSjd8n7rN46ymW7Ltt8GM/s1600/Saturn's+North+Polar+Vortex+and+Rings+by+Cassini.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgA1r51dc76KiUjd_IljOj5W88AvrJSbgNcvxPa7mNa_xXz_nNr852YKwClz2Y_8noom56NDT4sONLrGp1ou1K1XcCumNI7Nd1oqDy0wG1pc6ujtt1wSbb3RrSmSjd8n7rN46ymW7Ltt8GM/s1600/Saturn's+North+Polar+Vortex+and+Rings+by+Cassini.jpg" height="590" width="640" /></a></div><br />
<blockquote>The Cassini spacecraft captures three magnificent sights at once: Saturn's north polar vortex and hexagon along with its expansive rings.<br />
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The hexagon, which is wider than two Earths, owes its appearance to the jet stream that forms its perimeter. The jet stream forms a six-lobed, stationary wave which wraps around the north polar regions at a latitude of roughly 77 degrees North.<br />
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This view looks toward the sunlit side of the rings from about 37 degrees above the ringplane. The image was taken with the Cassini spacecraft wide-angle camera on April 2, 2014 using a spectral filter which preferentially admits wavelengths of near-infrared light centered at 752 nanometers.<br />
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The view was obtained at a distance of approximately 1.4 million miles (2.2 million kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 43 degrees. Image scale is 81 miles (131 kilometers) per pixel.</blockquote><br />
<b>Image credit:</b> <a href="http://photojournal.jpl.nasa.gov/catalog/PIA18274">NASA/JPL-Caltech/Space Science Institute</a>JDsghttp://www.blogger.com/profile/04735390644321868222noreply@blogger.com0