Titan Images 2012

A recent research reveals striking similarities between Ontario Lacus, the largest body of liquids in the south polar region of Saturn's largest moon Titan and Etosha Pan, a salt pan forming a part of the Kalahari Basin in the north of Namibia.
The image in the left part of the mosaic above corresponds to a radar view of the dark Ontario Lacus obtained with the radar instrument of the Cassini spacecraft on January 12, 2010. The image in the right part of the mosaic corresponds to the Etosha Pan. The view was acquired by a NASA and USGS Landsat satellite on January 21, 2003. The arrow in each portion indicates the north direction.
The Etosha Pan covers an area approximately 75 by 40 miles (120 by 65 kilometers) whereas Ontario Lacus is slightly bigger with a surface area of about 140 by 47 miles (230 by 75 kilometers). The south part of Ontario Lacus appears brighter suggesting a lower level of liquid hydrocarbons than the north part. Linear landforms can be identifed inside Ontario Lacus.
The salt Pan "Etosha Pan" is a lake bed, mostly dry, that probably lost a large portion of its water content following a natural deflection, triggered by tectonic movements, of a river channel which used to fuel the lake with water. Heavy rainfall can trigger a rapid rise in the water level of Etosha Pan. The layers of water which evaporate leave sediments like tide marks showing the previous extent of the water.

Image Credit: NASA/JPL-Caltech and NASA/USGS

This image obtained in visible green light with the Narrow-Angle Camera of the Cassini probe on March 12, 2012 reveals the bright, white moon Enceladus in front of Saturn's largest moon Titan as well as the rings of the Gas Giant.
Enceladus is well know for its highly reflective surface and for its geysers or jets of water ice and vapor taking shape in the south polar region of the icy moon. Those geysers suggest the presence of a subsurface sea rich in organics. The Opaque Moon Titan is well known for its deep, thick and opaque atmosphere and for its lakes and seas of hydrocarbons (methane, ethane...) in the south polar region and in the north polar region.
The small moon Enceladus, appearing in the center of the image, is only 313 miles or 504 kilometers across whereas the giant moon Titan is 3,200 miles or 5,150 kilometers across. Titan is moving well beyond the rings and Enceladus.
The view was taken at a distance of about 600,000 miles or 1 million kilometers from Enceladus and at a Sun-Enceladus-spacecraft, or phase, angle of 36 degrees. The camera is orientated toward the anti-Saturn side of Enceladus and the Saturn-facing side of the Orange Moon Titan. The northern, illuminated side of the rings of Saturn is observed from just above the ringplane.

Image Credit: NASA/JPL-Caltech/Space Science Institute

This natural color view of Saturn's largest moon Titan, reminiscent of a moving tennis ball, reveals its orange atmosphere, the dark north polar hood or vortex as well as a blue detached haze layer in the upper part of the atmosphere. The blue haze can be clearly seen above the north polar region and above the south pole at the bottom of the image. Recent images acquired from the Cassini spacecraft suggest that the north polar vortex is beginning to flip from north to south. The atmospheric dynamics and meteorological phenomena may be closely related to seasonal changes.
The camera is orientated toward the anti-Saturn side of the Opaque Moon and north is up. Images obtained using red, green and blue spectral filters were combined to generate this natural color view. The views were captured with the Wide-Angle Camera of the Cassini spacecraft on January 30, 2012 at a distance of about 119,000 miles or 191,000 kilometers from Titan.

Image Credit: NASA/JPL-Caltech/Space Science Institute

This near-infrared view reveals the Ringed Planet Saturn as well as its largest moon Titan, 3,200 miles or 5,150 kilometers across, in the right part of the image below the rings. Prometheus can be noticed, as well, just above the rings in the far upper right of the view. The tiny moon Prometheus, about 53 miles or 86 kilometers across, appears as a tiny white spot.
The shadow cast by the bright, elongated moon Prometheus can be observed as a small black speck on the Gas Giant on the far left of the view, between the shadows cast by the main rings and the thin F ring. The shadow of the small moon Pandora, about 81 kilometers or 50 miles across, can be observed, as well, on the Gas Giant south of the shadows of all the rings, below the center of the view towards the right side of Saturn.
The camera of the Cassini probe is orientated toward the southern, unilluminated side of the rings from approximately 1 degree below the ringplane. The image was obtained with the wide-angle camera of the Cassini probe on January 5, 2012 using a spectral filter sensitive to wavelengths of near-infrared radiation centered at 752 nanometers. The image was taken at a distance of about 426,000 miles or 685,000 kilometers from the Gas Giant and at a Sun-Titan-spacecraft, or phase, angle of 20 degrees.

Image Credit: NASA/JPL-Caltech/Space Science Institute

The artistic view above unveils a model of the internal structure of Saturn's largest moon Titan, developed by Dominic Fortes of University College London, England on the basis of data from Cassini's radio science experiment.
The artistic image shows the Cassini spacecraft performing a targeted flyby over Titan's cloudtops. One can notice the Gas Giant Saturn and the icy moon Enceladus on the horizon, appearing at upper right.
The model is based on the assumption that the sphere is fully differentiated, which implies that the denser core of Titan has separated from its outer parts.
The core is believed to be composed of water-bearing rocks. The core is thought to be covered by a high-pressure ice layer. A subsurface ocean may exist between the mantle consisting of water ice and the high-pressure ice layer closer to the core. The soil and the atmosphere of Titan may be rich in organics or hydrocarbons.

Image Credit: A. D. Fortes/UCL/STFC

The false-color images above taken by the Visual and Infrared Mapping Spectrometer (VIMS) of the Cassini spacecraft reveal the evolution of the cloud systems in the north polar region of Saturn's largest moon, Titan from 2006 to 2009. One can notice, in particular, a dissolving cloud cover in the high latitudes of the northern hemisphere due to the seasonal changes.
A relationship can be established between the amount of clouds in the north polar region and the seasonal factors. In August 2009, the equinox occured on Titan, marking the end of the winter season and the start of the spring season in the northern hemisphere. Each Titanian season lasts approximately 7 Terrestrial years. One can observe that, in 2006, the north polar cloud system appeared dense and opaque. By contrast, the north polar cloud system appeared much thinner and patchier in 2009 during the transition period between the winter season and the spring season in the northern hemisphere.
Thanks to a lower level of cloud cover or dissipating clouds, planetary scientists were able to identify the underlying northern lakes and seas such as the dark Kraken Mare. The seas, lakes and rivers in the northern hemisphere are believed to be composed of liquid hydrocarbons such as methane and ethane.
The VIMS views were colorized with red, green and blue colors assigned to the parts of the infrared spectrum around 5 micrometers, 2.8 micrometers and 2.03 micrometers, respectively. The images generate a kind of time-lapse series from December 28, 2006 to June 6, 2009, from the 23rd, 24th, 30th, 43rd, 44th, 45th, 52nd, 53rd, 55th and 57th time the Cassini probe flew by the Orange Moon.
The mosaic in the lower part of the table shows pairs of images. The false-color images of the clouds can be seen in the left part of each couple of views. The same views are re-projected onto a globe of the Opaque Moon on the right. The global view reveals the north pole of the moon at the center. Other parts of the globe are filled in on the basis of data obtained with the imaging cameras and the radar instrument of the Cassini probe.

Image Credit, upper view: NASA/JPL-Caltech/University of Arizona/CNRS/LPGNantes
Image Credit, lower view: NASA/JPL-Caltech/University of Arizona/CNRS/LPGNantes/SSI

The view above shows the icy moon Rhea moving in front of Saturn's largest moon Titan. One can clearly notice the cratered surface of the bright Rhea and the opaque, orange atmosphere of Titan. The detached-haze layer of the deep atmosphere of Titan is also clearly visible, here.
Rhea is largely smaller than Titan: its diameter is only 949 miles or 1,528 kilometers compared to 3,200 miles or 5,150 kilometers for Titan. Rhea is orbiting closer to Saturn than Titan with a semi-major axis of 527,108 km (approximately 328,000 miles) compared to 1,221,870 km (approximately 760,000 miles) for Titan.
The illuminated terrain observed here appears on the leading hemisphere of Rhea and Titan. North on each moon is up and rotated 13 degrees to the left. The edge of the visible disk of Rhea is slightly overexposed in this image.
This image was obtained in visible green light with the narrow-angle camera of the Cassini probe on December 10, 2011. The view was taken at a distance of about 1.2 million miles or 2 million kilometers from the Orange Moon and at a Sun-Titan-spacecraft, or phase, angle of 109 degrees. The image was captured at a distance of approximately 810,000 miles or 1.3 million kilometers from Rhea and at a Sun-Rhea-probe, or phase, angle of 109 degrees.

Image Credit: NASA/JPL-Caltech/Space Science Institute

The mosaic above shows four areas of dune fields on Earth and on Titan. The topographic portions have been processed to show the same spatial scale and stretch. The images of the Belet dunes and the Fensal dunes on the left part of the mosaic correspond to radar views obtained by the radar instrument of the Cassini probe on October 28, 2005 and April 10, 2007. The image of the Oman dunes, corresponding to dunes in the Rub' al Khali or Empty Quarter, as well as the image of the Kalahari dunes, in the Namib desert, were taken by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), an instrument aboard NASA's Terra satellite.
The dunes on Titan are the dark streaks of the radar images. One can notice that the area of Fensal appears much brighter than the area of Belet. The difference in appearance may be explained by a thinner sand cover in the interdune areas of Fensal. One can also notice that the areas between the dunes are wider in Fensal than in the dune field of Belet. The dunes on Titan are 0.6 to 1.2 miles wide or 1 to 2 kilometers wide and the areas between the dunes represented by bright streaks in the radar views are 0.6 miles to 2.5 miles wide or 1 to 4 kilometers wide.
It appears that the shape and the size of the dunes are intimately linked to altitude and latitude on Titan. The dunes tend to be thinner and more widely separated in areas of higher altitude or higher latitude. Thus Fensal has less sand than Belet with narrower dunes and thinner blankets of sand between them because Fensal is found at a higher altitude and latitude than Belet. The Fensal dunes are relatively similar to the Kalahari dunes in South Africa and Namibia where there is a limited amount of sediment or sand. By contrast, the Belet dunes resemble the Oman dunes in Yemen and Saudi Arabia where there is a large amount of sand or sediment.
The difference in the size of the dunes between Belet and Fensal may be explained by meteorological phenomena. The high latitudes tend to be more wet than the lower latitudes so that the sand grains likely made of hydrocarbons are sticky, heavier and less mobile. As a result, the dunes will be thinner. Due to the obliquity of Titan, the high latitudes of Titan experience more rain, more evaporation and condensation than the low latitudes. Rainfall may be rare in the low latitudes so that the soil is relatively dry with a large amount of volatile compounds such as sand grains of hydrocarbons.
The dunes in the southern hemisphere may be more pronounced because the rainy season corresponding to summer may be shorter and warmer leaving the soil less moist. This climate particularity is related to the elliptical orbit of Titan around the Sun. Titan receives more solar energy at perihelion than at aphelion. At perihelion, the southern hemisphere experiences the warm season in which the area will receive short and intense precipitation. This warm season in the southern hemisphere is shorter than in the northern hemisphere because Titan moves faster around the Sun (Kepler's Law of Areas) during that period. Therefore, the dry season will be longer and the dunes will likely be thicker.

Image Credit: NASA/JPL-Caltech, and NASA/GSFC/METI/ERSDAC/JAROS and U.S./Japan ASTER Science Team

The image above shows the icy moon Tethys, the Opaque Moon Titan as well as a portion of Saturn's rings. The Orange Moon Titan appears beyond the rings in the left part of the view and the bright Tethys which is moving closer to Saturn appears beyond the rings in the middle of the view.
The image was obtained in visible red light with the narrow-angle camera of the Cassini probe on December 7, 2011. The view was taken at a distance of about 1.4 million miles or 2.2 million kilometers from Tethys and 1.9 million miles or 3.1 million kilometers from Saturn's largest moon Titan.
The camera is orientated toward the Saturn-facing sides of Tethys and Titan. The northern, sunlit side of the rings of the Gas Giant can be observed from an angle of less than one degree above the ring plane.
Tethys is largely smaller than Titan with a mean diameter of only 660 miles or 1,062 kilometers compared to 3,200 miles or 5,150 kilometers for Titan.

Image Credit: NASA/JPL-Caltech/Space Science Institute