“Bird’s” eye view of Saturn’s moon Iapetus
January 13th 2008 04:32
Cassini is a joint NASA/ESA project designed to accomplish an exploration of the Saturnian system with its Cassini Saturn Orbiter and Huygens Titan Probe.Cassini was launched aboard a Titan IV/Centaur 1997.
The Cassini spacecraft has been operational for the past eleven years now the images form Saturn are amazing, Iapetus was first discovered by Italian astronomer Giovanni Cassini in 1671.
NASA’S Cassini orbiter has taken hundreds of images of Saturn's moon Iapetus during a flyby in September 2007 images from the spacecraft are crisp and in shinning detail. lapetus's is a very difficult to image due to the lighting variable contrast.
at its equator, and the stark contrast between the surface brightness of the moon's hemispheres is a mystery.
All three images shown here were taken along the equatorial ridge, and the lower side of the moon. Iapetus is not very big moon the overall size is 3,561,000 km and much like our own moon keeps the same side facing Saturn due to its slow rotation.
In Greek mythology Iapetus was a Titan, the son of Uranus, the father of Prometheus and Atlas.
With a density of only 1.1, Iapetusis is most probably composed almost entirely of water ice.
One explanation of this is that the leading hemisphere is dusted with a coating of material knocked off of Phoebe or some other Saturnian Moons. However, the color of the leading half of Iapetus and that of Phoebe don't quite match. Another possibility is that some active process within Iapetus is responsible. The puzzle is compounded by the fact that the dividing line between the two sides is inexplicably sharp.
Cassini made its first close encounter with Iapetus. The images show that the dark material overlays the topography, indicating that it is relatively young. And as in the image to the left, along the edge of the dark area there are many craters where only one side is covered by the dark material; the boundary between the two regions isn't so sharp after all. So far the Cassini's data do not resolve the puzzle of the origin of the dark material but there's more another feature is Iapetus's giant equatorial ridge. Another striking feature not seen before a ridge 13 kilometers higher than the surrounding terrain that extends at least 1300 km almost exactly parallel with Iapetus's equator.
These views feature Iapetus' trailing hemisphere, which is its bright hemisphere. Remember that Iapetus, like nearly all moons in the solar system, is locked in synchronous rotation with Saturn, so that the same face (the "sub-Saturnian hemisphere") points toward Saturn all the time, which means that one side always faces forward along the orbit, and one side always faces the rear. Views of the trailing hemisphere with nice sunlight represent a bit of a change. For much of Cassini's mission, the best views have been of the leading hemisphere.
The spacecraft completed its latest flyby on September 10th, 2007, skimming just 1,640 km above the moon's surface. Scientists will be digesting the photographs for years.
During this most recently flyby, Cassini passed 100 times closer than its previous Iapetus flyby in 2004. At this distance, the spacecraft was able to reveal the moon's strange bulging shape, equatorial ridge, and pattern of bright and darkness across its features.
Many of its photographs focus in on the bizarre mountain ridge that circles the moon's equator, like a seam. The new Cassini images showed that this ridge is mountainous, rising as high as 20 km, and extends across more than half its circumference.
The mystery deepens what caused this vast contrast between light and dark regions?. Maybe some previous Saturnian moon broke up, and ejected Iapetus dark material during impact. Or maybe the material is volcanic that rose up from within the moon. And this could explain why the ridge is there.
Sarurn with the rings tilted
The Cassini spacecraft has been operational for the past eleven years now the images form Saturn are amazing, Iapetus was first discovered by Italian astronomer Giovanni Cassini in 1671.
NASA’S Cassini orbiter has taken hundreds of images of Saturn's moon Iapetus during a flyby in September 2007 images from the spacecraft are crisp and in shinning detail. lapetus's is a very difficult to image due to the lighting variable contrast.
One of Saturn's Moon's showing Iapetus unusual mountainous ridge
Image showing some of the lighter region's of Iapetus surface
In Greek mythology Iapetus was a Titan, the son of Uranus, the father of Prometheus and Atlas.
With a density of only 1.1, Iapetusis is most probably composed almost entirely of water ice.
One explanation of this is that the leading hemisphere is dusted with a coating of material knocked off of Phoebe or some other Saturnian Moons. However, the color of the leading half of Iapetus and that of Phoebe don't quite match. Another possibility is that some active process within Iapetus is responsible. The puzzle is compounded by the fact that the dividing line between the two sides is inexplicably sharp.
A closer look of the "ridge"
Cassini made its first close encounter with Iapetus. The images show that the dark material overlays the topography, indicating that it is relatively young. And as in the image to the left, along the edge of the dark area there are many craters where only one side is covered by the dark material; the boundary between the two regions isn't so sharp after all. So far the Cassini's data do not resolve the puzzle of the origin of the dark material but there's more another feature is Iapetus's giant equatorial ridge. Another striking feature not seen before a ridge 13 kilometers higher than the surrounding terrain that extends at least 1300 km almost exactly parallel with Iapetus's equator.
These views feature Iapetus' trailing hemisphere, which is its bright hemisphere. Remember that Iapetus, like nearly all moons in the solar system, is locked in synchronous rotation with Saturn, so that the same face (the "sub-Saturnian hemisphere") points toward Saturn all the time, which means that one side always faces forward along the orbit, and one side always faces the rear. Views of the trailing hemisphere with nice sunlight represent a bit of a change. For much of Cassini's mission, the best views have been of the leading hemisphere.
The spacecraft completed its latest flyby on September 10th, 2007, skimming just 1,640 km above the moon's surface. Scientists will be digesting the photographs for years.
Another view of Iapetus showing a more detailed view of the surface topography.
During this most recently flyby, Cassini passed 100 times closer than its previous Iapetus flyby in 2004. At this distance, the spacecraft was able to reveal the moon's strange bulging shape, equatorial ridge, and pattern of bright and darkness across its features.
Many of its photographs focus in on the bizarre mountain ridge that circles the moon's equator, like a seam. The new Cassini images showed that this ridge is mountainous, rising as high as 20 km, and extends across more than half its circumference.
The mystery deepens what caused this vast contrast between light and dark regions?. Maybe some previous Saturnian moon broke up, and ejected Iapetus dark material during impact. Or maybe the material is volcanic that rose up from within the moon. And this could explain why the ridge is there.
| 55 |
| Vote |
Add To: 
Subscribe to this blog
