| Piú votate - Artistic Views of the Solar System |
030-OPP-SOL209.jpgOver the Walls of Endurance (1)...89 visiteIpotesi di alba Marziana con il Sole capace di esprimere la stessa luminosit che percepibile dalla Terra.
(11 voti)
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Spirit2-19-DDM-04-Rover-A113R1.jpgI like to "roll" on Mars!!!86 visiteUn'interpretazione "artistica" (ma fortemente legata alla realt fattuale) del Rover Spirit mentre cammina (anzi: rolls...) sulla superficie di Gusaev Crater - Marte.
E' un disegno, naturalmente, ma estremamente bello e suggestivo il quale ci ricorda, come d'altronde noi abbiamo gi fatto tantissime volte, che la Scienza non solo calcolo e razionalit: la Scienza, in quanto tale, Arte!...
(11 voti)
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Venus fly-by.jpgCassini-Huygens during the Venus fly-by82 visitenessun commento
(11 voti)
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Mars-B.jpgMars, SOME time ago...104 visitenessun commento
(10 voti)
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032-OPP-SOL209.jpgOver the Walls of Endurance... (2)103 visiteImmagine in cui il Sole, ora, esprime un terzo in meno della luminosit percepibile dalla Terra. Notate una differenza?
(10 voti)
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Titan_s Rain~0.jpgTitan's "Rain"...93 visiteDa "NASA - Picture of the Day" del 2 Agosto 2006:"Might it rain cold methane on Saturn's Titan? Recent analyses of measurements taken by the Huygen's probe that landed on Titan in 2005, January, indicate that the atmosphere is actually saturated with methane at a height of about 8 Km. Combined with observations of a damp surface and lakes near the Poles, some astrobiologists conclude that at least a methane drizzle is common on parts of Titan. Other astrobiologists reported computer models of the clouded moon that indicate that violent methane storms might even occur, complete with flash floods carving channels in the landscape. The later scenario is depicted in the above drawing of Titan. Lighting, as also depicted above, might well exist on Titan but has not been proven. The findings increase speculation that a wet Titanian surface might be hospitable to unusual forms of life".
Attenzione all'ultima frase: "Queste scoperte fanno crescere (la validit) di una ipotesi speculativa secondo cui la superficie di Titano, laddove effettivamente umida, potrebbe essere idonea ad ospitare "inusuali" forme di Vita".
Il significato e la portata di questa frase sono evidenti e di valore storico, ma c' una domanda che ci incuriosisce e, in fondo, un p ci turba: cosa intende la NASA quando parla di "unusual life forms"?...
(10 voti)
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Kuiper_s Belt.jpgRelationship of the Kuiper's Belt to the Oort's Cloud92 visiteThis illustration shows that the Kuiper Belt is shaped like a disk (see inset diagram) and resides within the shell-like structure of the Oort Cloud. Located on the outskirts of the Solar System, the Kuiper Belt is a "junkyard" of countless icy bodies left over from the Solar System's formation. The Oort Cloud is a vast shell of billions of comets.
The inset diagram compares Pluto's orbit with a Kuiper Belt binary object called 1998 WW31. The Kuiper Belt [the fuzzy disk] extends from inside Pluto's orbit to the edge of the Solar System.
(10 voti)
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Enceladus-PIA07724.jpgEnceladus, Great Britain and Northern France145 visiteSaturn's moon Enceladus is only 505 Km (approx. 314 miles) across, small enough to fit within the length of the United Kingdom, as illustrated here. The intriguing icy moon also could fit comfortably within Arizona or Colorado.
(10 voti)
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Huygens to Titan-IMG001244-br500.jpgHuygens probe's going to Titan114 visiteAn artist's concept of the European Space Agency's Huygens Probe en route to Titan after release from the NASA Cassini orbiter.
(10 voti)
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Landing on Titan.jpgLanding on Titan119 visiteBecause it's in a deep freeze state, Titan's atmosphere is thought to contain chemicals similar to those found on Earth's early days. Data from the Huygens probe combined with Cassini's measurements may offer clues about how life began on Earth.
(10 voti)
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Titan-PIA11001.jpgEthane Lake on Titan113 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
(9 voti)
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Earth From Mars.jpgMy "Day", your "Night"117 visiteThough Earthlings will be able to get a good look at Mars during close approach, NASA's 2 Rovers on Mars will not be able to see Earth. That's because at the moment, Earth is on the daytime side of Mars. As shown in the top half of this artist's rendering, when it's nighttime on Earth, it's daytime on Mars. After Earth passes Mars, the Rovers will be able to see the sunlit side of Earth again just before dawn. The bottom half of this illustration shows what the Rovers would see if they looked toward Earth.
(9 voti)
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