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Volcanoes-Tharsis_Tholus-MGS.jpgPit-chain near Tharsis Tolus (MULTISPECTRUM; credits: Lunexit)61 visitenessun commentoMareKromium
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SOL702-1.jpgMartian "Trapdoor" or Martian "Sandglass"? - Sol 702 (natural colors + MULTISPECTRUM; credits: Dr G. Barca & Lunexit)61 visitenessun commentoMareKromium
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SOL725-1-2.jpgUnusually-looking Boulders - Sol 725 (ctx frame - natural colors + MULTISPECTRUM; credits: Dr G. Barca & Lunexit)61 visitenessun commentoMareKromium
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M-101-SST.jpgM 101 - Spiral Galaxy (a.k.a.: The "Pinwheel Galaxy")61 visite"...He brought him outside and said, "Look toward Haeven and count the Stars, if you are able to count them"..."
- Genesis 15:5MareKromium
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Titan-PIA11001.jpgEthane Lake on Titan61 visiteNASA scientists have concluded that at least one of the large lakes observed on Saturn's moon Titan contains liquid hydrocarbons, and have positively identified the presence of ethane. This makes Titan the only body in our solar system beyond Earth known to have liquid on its surface.
Scientists made the discovery using data from an instrument aboard the Cassini spacecraft. The instrument identified chemically different materials based on the way they absorb and reflect infrared light. Before Cassini, scientists thought Titan would have global oceans of methane, ethane and other light hydrocarbons. More than 40 close flybys of Titan by Cassini show no such global oceans exist, but hundreds of dark, lake-like features are present. Until now, it was not known whether these features were liquid or simply dark, solid material.
"This is the first observation that really pins down that Titan has a surface lake filled with liquid," said Bob Brown of the University of Arizona, Tucson. Brown is the team leader of Cassini's visual and mapping instrument. The results will be published in the July 31 issue of the journal Nature.
Ethane and several other simple hydrocarbons have been identified in Titan's atmosphere, which consists of 95 percent nitrogen, with methane making up the other fiver percent. Ethane and other hydrocarbons are products from atmospheric chemistry caused by the breakdown of methane by sunlight.
Some of the hydrocarbons react further and form fine aerosol particles. All of these things in Titan's atmosphere make detecting and identifying materials on the surface difficult, because these particles form a ubiquitous hydrocarbon haze that hinders the view. Liquid ethane was identified using a technique that removed the interference from the atmospheric hydrocarbons.
The visual and mapping instrument observed a lake, Ontario Lacus, in Titan's south polar region during a close Cassini flyby in December 2007. The lake is roughly 20,000 square kilometers (7,800 square miles) in area, slightly larger than North America's Lake Ontario.
"Detection of liquid ethane confirms a long-held idea that lakes and seas filled with methane and ethane exist on Titan," said Larry Soderblom, a Cassini interdisciplinary scientist with the U.S. Geological Survey in Flagstaff, Ariz. "The fact we could detect the ethane spectral signatures of the lake even when it was so dimly illuminated, and at a slanted viewing path through Titan's atmosphere, raises expectations for exciting future lake discoveries by our instrument."
The ethane is in a liquid solution with methane, other hydrocarbons and nitrogen. At Titan's surface temperatures, approximately 300 degrees Fahrenheit below zero, these substances can exist as both liquid and gas. Titan shows overwhelming evidence of evaporation, rain, and fluid-carved channels draining into what, in this case, is a liquid hydrocarbon lake.
Earth has a hydrological cycle based on water and Titan has a cycle based on methane. Scientists ruled out the presence of water ice, ammonia, ammonia hydrate and carbon dioxide in Ontario Lacus. The observations also suggest the lake is evaporating. It is ringed by a dark beach, where the black lake merges with the bright shoreline. Cassini also observed a shelf and beach being exposed as the lake evaporates. "During the next few years, the vast array of lakes and seas on Titan's north pole mapped with Cassini's radar instrument will emerge from polar darkness into sunlight, giving the infrared instrument rich opportunities to watch for seasonal changes of Titan's lakes," Soderblom said.
More information is available at: http://www.nasa.gov/cassini, http://saturn.jpl.nasa.gov and http://wwwvims.lpl.arizona.edu .
MareKromium
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Psp_008982_1965_red.jpgLayered Deposits in Arabia Terra Region (natural colors; credits: Lunexit)61 visiteThis image shows the floor of an Unnamed Impact Crater in Arabia Terra that has Layered Deposits. There are many craters in this Region, where layering is observed.
These layers are often exposed along the sides of large isolated mounds, small knobs and mesas, and other positive relief features. In some cases, the layering is expressed as narrow sinuous ridge-like structures along crater floors.
The presence of Layered Deposits is of particular interest because these materials are not likely to be related to the impact event, but rather post-impact infill of the Crater. Modification of the Deposits has now revealed layers of material.
HiRISE and other instruments onboard the Mars Reconnaissance Orbiter may provide more clues to the origin of the these deposits.MareKromium
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PHOE-SOL069-MF.jpgLooking at the "Trench" - Sol 69 (Superdefinition and natural colors; credits: Dr M. Faccin)61 visitenessun commentoMareKromium
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20000322.jpg433-Eros in HR (True Colors; credits: NASA)61 visiteAs the NEAR Shoemaker spacecraft descends into lower orbits around Eros, it continually returns higher spatial resolution images of the asteroid. The true color image at left was taken February 12, 2000, from a range of 1748 Km (about 1083 miles), and shows details only as small as 180 meters (590 feet) across.
It was taken two days before orbit insertion, as part of an image sequence designed to provide moderate-resolution color mapping of Eros at a near-constant viewing geometry.
The true color image inset at right was taken February 29 from a range of 283 Km (about 175 miles) and shows much smaller details only 27 meters (89 feet) across.
The higher spatial resolution (by a factor of 6) brings out a whole class of surface details that were either invisible or at the margin of visibility in the earlier images. For example, the bright material on the wall of the large crater in the inset image is barely evident in the lower-resolution image at left, but by virtue of its limited spatial coverage the inset image lacks information on the crater's regional geologic setting. NEAR Shoemaker's imaging strategy makes use of both types of images, with lower-resolution images providing "context" for higher-resolution images that bring specific features into sharper focus.
(Product of images 0125748893, 0125748895, 0125748897, 0127229466, 0127229468, 0127229470)
MareKromium
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Enceladus-N00118363.jpgThe Unbelievable Surface of Enceladus, from about 1500 Km!61 visiteCaption NASA:"Caption NASA:"N00118365.jpg was taken on August 11, 2008 and received on Earth August 12, 2008. The camera was pointing toward ENCELADUS that, at the time, was approximately 1564 Km away.
The image was taken using the CL1 and CL2 filters and it has not been validated or calibrated".
Nota Lunexit: osservate come l'avvicinarsi alla Linea del Terminatore rende le immagini straordinariamente affilate e dense di profondità ...MareKromium
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OPP-SOL1615-1.jpgFrom inside Victoria - Sol 1615 (Enhanced RAW Natural Colors; credits for thge additional process. and color.: Dr Gianluigi Barca - Lunexit Team)61 visitenessun commentoMareKromium
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The_Rings-PIA10454.jpgOut of the Darkness (natural colors; credits: NASA)61 visiteCaption NASA:"Saturn's rings burst out of shadow and curve gracefully around the Planet.
Prometheus (86 Km, or 53 about miles across at its widest point) appears as a bright speck touching the inside of the narrow F-Ring. Atlas (30 Km, or approx. 19 miles across at its widest point) is also visible, faintly, upward and to the left of Prometheus, just outside the A-Ring edge. Saturn's shadow cuts across the Rings at top right.
Several dark, narrow spokes are faintly visible near the B-Ring ansa, left of center.
This view looks toward the unilluminated side of the Rings from about 13° above the Ring-Plane. Images taken using red, green and blue spectral filters were combined to create this natural color view. The images were obtained with the Cassini Spacecraft wide-angle camera on July 4, 2008 at a distance of approx. 1,2 MKM (about 775.000 miles) from Saturn.
Image scale is roughly 71 Km (about 44 miles) per pixel".MareKromium
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Channels-Unnamed_Channel-20071213a~0.jpgUnnamed Channel (Natural Colors/Tri-Chromatic Version; credits: Dr Paolo C. Fienga - Lunexit Team)61 visitenessun commentoMareKromium
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