|
|
Propeller Motion
| Description |
Propeller Motion |
| Full Description |
This magnified view illustrates the general orientation of the "propeller" features in Saturn's rings as they orbit the planet. The propellers are features detected in Cassini images that reveal the gravitational influence of moonlets approximately 100 meters (300 feet) in diameter. The view is from one of the two Saturn orbit insertion images, taken on July 1, 2004, in which the propellers were discovered. The two dashes of the propeller are oriented in the direction of orbital motion. The "leading" dash is also slightly closer to Saturn, this "radial offset" is about 300 meters (1000 feet). The unseen moonlet lies in the center of the structure. The grainy appearance of the image is due to magnification and the fact that the propellers are very faint--just visible above the level of background noise. Consequently, the image enhancement procedures used have also enhanced the noise. This propeller image is identified as "feature 1" in Four Propellers. The original Cassini spacecraft narrow-angle camera image has been magnified from its original scale for presentation. 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. 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 |
March 29, 2006 |
|
Four Propellers
| Description |
Four Propellers |
| Full Description |
These figures show four propeller-shaped structures discovered by the Cassini spacecraft in close-up images of Saturn's A ring. The propellers are about 5 kilometers (3 miles) long from tip to tip, and the radial offset (the "leading" dash is slightly closer to Saturn) is about 300 meters (1,000 feet). See Propeller Motion and Locating the Propellers for additional images and information about these features. The figures were cropped from two original Cassini spacecraft narrow-angle camera images and magnified for visibility. The images were then re-projected so that orbital motion is to the left and Saturn is up. The unseen moonlets lie in the center of each structure. The figures were cropped from two original Cassini spacecraft narrow-angle camera images, taken during Saturn orbit insertion on July 1, 2004, and magnified for 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 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 |
March 29, 2006 |
|
Locating the Propellers
| Description |
Locating the Propellers |
| Full Description |
This collection of Cassini images provides context for understanding the location and scale of propeller-shaped features observed within Saturn's A ring. Careful analysis of the highest resolution images taken by Cassini's cameras as the spacecraft slipped into Saturn orbit revealed the four faint, propeller-shaped double-streaks in an otherwise bland part of the mid-A ring. Imaging scientists believe the "propellers" provide the first direct observation of the dynamical effects of moonlets approximately 100 meters (300 feet) in diameter. The propeller moonlets represent a hitherto unseen size-class of particles orbiting within the rings. The left-hand panel provides broad context within the rings, and shows the B ring, Cassini Division, A ring and F ring. Image scale in the radial, or outward from Saturn, direction is about 45 kilometers (28 miles) per pixel, because the rings are viewed at an angle, the image scale in the longitudinal, or circumferential, direction is several times greater. The center image is a closer view of the A ring, showing the radial locations where propeller features were spotted. The view is approximately 1,800 kilometers (1,100 miles) across from top to bottom and includes a large density wave at bottom (caused by the moons Janus and Epimetheus), as well as two smaller density waves. The footprints of the propeller discovery images are between density waves, in bland, quiescent regions of the ring. The propellers appear as double dashes in the two close-up discovery images at the right and are circled. The unseen moonlets, each roughly the size of a football field, lie in the center of each structure. These two images were taken during Saturn orbit insertion on July 1, 2004, and are presented here at one-half scale. Resolution in the original images was 52 meters (171 feet) per pixel. The horizontal lines in the image represent electronic noise and do not correspond to ring features. The propellers are about 5 kilometers (3 miles) long from tip to tip, and the radial offset (the "leading" dash is slightly closer to Saturn) is about 300 meters (1,000 feet). The propeller structures are unchanged as they orbit the planet. In that way, they are much like the wave pattern that trails after a speedboat as it skims across a smooth lake. Such a pattern is hard to discern in a choppy sea. In much the same way, scientists think other effects may be preventing Cassini from seeing the propellers except in very bland parts of the rings. See Four Propellers and Propeller Motion for additional images showing these features. 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 |
March 29, 2006 |
|
Locating the Propellers
| title |
Locating the Propellers |
| date |
07.01.2004 |
| description |
This collection of Cassini images provides context for understanding the location and scale of propeller-shaped features observed within Saturn's A ring. Careful analysis of the highest resolution images taken by Cassini's cameras as the spacecraft slipped into Saturn orbit revealed the four faint, propeller-shaped double-streaks in an otherwise bland part of the mid-A ring. Imaging scientists believe the "propellers" provide the first direct observation of the dynamical effects of moonlets approximately 100 meters (300 feet) in diameter. The propeller moonlets represent a hitherto unseen size-class of particles orbiting within the rings. The left-hand panel provides broad context within the rings, and shows the B ring, Cassini Division, A ring and F ring. Image scale in the radial, or outward from Saturn, direction is about 45 kilometers (28 miles) per pixel, because the rings are viewed at an angle, the image scale in the longitudinal, or circumferential, direction is several times greater. The center image is a closer view of the A ring, showing the radial locations where propeller features were spotted. The view is approximately 1,800 kilometers (1,100 miles) across from top to bottom and includes a large density wave at bottom (caused by the moons Janus and Epimetheus), as well as two smaller density waves. The footprints of the propeller discovery images are between density waves, in bland, quiescent regions of the ring. The propellers appear as double dashes in the two close-up discovery images at the right and are circled. The unseen moonlets, each roughly the size of a football field, lie in the center of each structure. These two images were taken during Saturn orbit insertion on July 1, 2004, and are presented here at one-half scale. Resolution in the original images was 52 meters (171 feet) per pixel. The horizontal lines in the image represent electronic noise and do not correspond to ring features. The propellers are about 5 kilometers (3 miles) long from tip to tip, and the radial offset (the "leading" dash is slightly closer to Saturn) is about 300 meters (1,000 feet). The propeller structures are unchanged as they orbit the planet. In that way, they are much like the wave pattern that trails after a speedboat as it skims across a smooth lake. Such a pattern is hard to discern in a choppy sea. In much the same way, scientists think other effects may be preventing Cassini from seeing the propellers except in very bland parts of the rings. 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 |
|
On the Origin of Gold
| Title |
On the Origin of Gold |
| Explanation |
Where did the gold [ http://www.goldinstitute.org/history/ ] in your jewelry originate? No one is completely sure [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1999ApJ...525L.121F ]. The relative average abundance in our Solar System [ http://www.nineplanets.org/overview.html ] appears higher than can be made in the early universe [ http://ultraman.ssl.berkeley.edu/nucleosynthesis.html ], in stars [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1997AAS...19112503P ], and even in typical supernova explosions [ http://heasarc.gsfc.nasa.gov/docs/snr.html ]. Some astronomers now suggest [ http://arxiv.org/abs/astro-ph/0012046 ] that neutron-rich heavy elements [ http://periodic.lanl.gov/ ] such as gold [ http://periodic.lanl.gov/elements/79.html ] might be most easily made [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1997LPI....28..947M ] in rare neutron [ http://en.wikipedia.org/wiki/Neutron ]-rich explosions such as the collision [ http://dast.nlanr.net/OH/Jn-sc98/sld001.htm ] of neutron stars [ http://imagine.gsfc.nasa.gov/docs/science/know_l1/pulsars.html ]. Pictured above [ http://www.ukaff.ac.uk/movies/nsmerger/ ] is a computer-animated frame depicting two neutron stars [ http://www.astro.umd.edu/~miller/nstar.html ] spiraling in toward each other, just before they collide [ http://www.ncsa.uiuc.edu/SCMS/DigLib/text/astro/Axisymmetric-Collision-Neutron-Stars-Evans.html ]. Since neutron star collisions [ http://woodall.ncsa.uiuc.edu/dbock/Vis/NeutronStar/Summary.html ] are also suggested as the origin of short [ http://imagine.gsfc.nasa.gov/docs/science/know_l1/short_grbs.html ] duration [ http://www.space.com/scienceastronomy/050509_blackhole_birth.html ] gamma-ray bursts [ http://antwrp.gsfc.nasa.gov/apod/ap980507.html ], it is possible that you already own a souvenir from one of the most powerful explosions [ http://antwrp.gsfc.nasa.gov/apod/ap020405.html ] in the universe. |
|
Propeller Motion
PIA07791
Saturn
Imaging Science Subsystem -
…
| Title |
Propeller Motion |
| Original Caption Released with Image |
This magnified view illustrates the general orientation of the "propeller" features in Saturn's rings as they orbit the planet. The propellers are features detected in Cassini images that reveal the gravitational influence of moonlets approximately 100 meters (300 feet) in diameter. The view is from one of the two Saturn orbit insertion images, taken on July 1, 2004, in which the propellers were discovered. The two dashes of the propeller are oriented in the direction of orbital motion. The "leading" dash is also slightly closer to Saturn, this "radial offset" is about 300 meters (1000 feet). The unseen moonlet lies in the center of the structure. The grainy appearance of the image is due to magnification and the fact that the propellers are very faint--just visible above the level of background noise. Consequently, the image enhancement procedures used have also enhanced the noise. This propeller image is identified as "feature 1" in PIA07790 [ http://photojournal.jpl.nasa.gov/catalog/PIA07790 ]. The original Cassini spacecraft narrow-angle camera image has been magnified from its original scale for presentation. 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/home/index.cfm [ http://saturn.jpl.nasa.gov ]. The Cassini imaging team homepage is at http://ciclops.org [ http://ciclops.org ]. |
|
Locating the Propellers
PIA07792
Saturn
Imaging Science Subsystem
| Title |
Locating the Propellers |
| Original Caption Released with Image |
This collection of Cassini images provides context for understanding the location and scale of propeller-shaped features observed within Saturn's A ring. Careful analysis of the highest resolution images taken by Cassini's cameras as the spacecraft slipped into Saturn orbit revealed the four faint, propeller-shaped double-streaks in an otherwise bland part of the mid-A ring. Imaging scientists believe the "propellers" provide the first direct observation of the dynamical effects of moonlets approximately 100 meters (300 feet) in diameter. The propeller moonlets represent a hitherto unseen size-class of particles orbiting within the rings. The left-hand panel provides broad context within the rings, and shows the B ring, Cassini Division, A ring and F ring. Image scale in the radial, or outward from Saturn, direction is about 45 kilometers (28 miles) per pixel, because the rings are viewed at an angle, the image scale in the longitudinal, or circumferential, direction is several times greater. The center image is a closer view of the A ring, showing the radial locations where propeller features were spotted. The view is approximately 1,800 kilometers (1,100 miles) across from top to bottom and includes a large density wave at bottom (caused by the moons Janus and Epimetheus), as well as two smaller density waves. The footprints of the propeller discovery images are between density waves, in bland, quiescent regions of the ring. The propellers appear as double dashes in the two close-up discovery images at the right and are circled. The unseen moonlets, each roughly the size of a football field, lie in the center of each structure. These two images were taken during Saturn orbit insertion on July 1, 2004, and are presented here at one-half scale. Resolution in the original images was 52 meters (171 feet) per pixel. The horizontal lines in the image represent electronic noise and do not correspond to ring features. The propellers are about 5 kilometers (3 miles) long from tip to tip, and the radial offset (the "leading" dash is slightly closer to Saturn) is about 300 meters (1,000 feet). The propeller structures are unchanged as they orbit the planet. In that way, they are much like the wave pattern that trails after a speedboat as it skims across a smooth lake. Such a pattern is hard to discern in a choppy sea. In much the same way, scientists think other effects may be preventing Cassini from seeing the propellers except in very bland parts of the rings. See PIA07790 [ http://photojournal.jpl.nasa.gov/catalog/PIA07790 ] and PIA07791 [ http://photojournal.jpl.nasa.gov/catalog/PIA07791 ], for additional images showing these features. 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/home/index.cfm [ http://saturn.jpl.nasa.gov ]. The Cassini imaging team homepage is at http://ciclops.org [ http://ciclops.org ]. |
|
Four Propellers
PIA07790
Saturn
Imaging Science Subsystem -
…
| Title |
Four Propellers |
| Original Caption Released with Image |
These figures show four propeller-shaped structures discovered by the Cassini spacecraft in close-up images of Saturn's A ring. The propellers are about 5 kilometers (3 miles) long from tip to tip, and the radial offset (the "leading" dash is slightly closer to Saturn) is about 300 meters (1,000 feet). See PIA07791 [ http://photojournal.jpl.nasa.gov/catalog/PIA07791 ] and PIA07792 [ http://photojournal.jpl.nasa.gov/catalog/PIA07792 ] for additional images and information about these features. The figures were cropped from two original Cassini spacecraft narrow-angle camera images and magnified for visibility. The images were then re-projected so that orbital motion is to the left and Saturn is up. The unseen moonlets lie in the center of each structure. The figures were cropped from two original Cassini spacecraft narrow-angle camera images, taken during Saturn orbit insertion on July 1, 2004, and magnified for 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 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/home/index.cfm [ http://saturn.jpl.nasa.gov ]. The Cassini imaging team homepage is at http://ciclops.org [ http://ciclops.org ]. |
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