| Piú votate - SOLAR SYSTEM |
Titan-Full_Disk-PIA06141_modest.jpgTitan (full disk, no haze) from 300.000 up to 650.000 Km67 visiteThe images that comprise the mosaic have been processed to reduce the effects of the atmosphere and to sharpen surface features. The mosaic has been trimmed to show only the illuminated surface and not the atmosphere above the edge of the moon. Pixel scales of the composite images vary from 2 to 4 Km per pixel. Surface features are best seen near the center of the disc, where the spacecraft is looking directly downwards; the contrast becomes progressively lower and surface features become fuzzier toward the outside, where the spacecraft is peering through haze, which washes out surface features. The brighter region on the right side and equatorial region is named Xanadu. Scientists are debating what processes may have created the bizarre surface brightness patterns seen here. The images hint at a young surface with no obvious craters. The exact nature of that activity, whether tectonic, wind-blown, fluvial, marine or volcanic is still unknown.
(25 voti)
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Tethys-PIA06526_modest.jpgTethys and the South Pole of Saturn84 visiteCaption NASA originale:"This dazzling view looks beyond gigantic storms near Saturn's South Pole to the small but clear disc of Tethys (1.060 Km across). Clouds and ribbons of gas swirl about in the planet's atmosphere in the foreground, while a tremendous chasm is visible on the icy moon. The image was taken with the Cassini spacecraft narrow angle camera on Oct. 18, 2004, at a distance of about 3.9 MKMs from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 61°. The view is in wavelengths of visible red light centered at 619 nanometers. The image scale is 23 Km per pixel".
(25 voti)
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Rhea-PIA06525_modest.jpgRhea from about 1.700.000 Km64 visiteCaption NASA originale:"Saturn's moon Rhea shows off the moon equivalent of a black eye: a bright, rayed crater near its eastern limb.
Rhea is about half the size of Earth's moon. At 1.528 Km across, it is the second-largest moon orbiting Saturn.
The image was taken in visible light with the Cassini spacecraft narrow angle camera on Oct. 24, 2004, at a distance of about 1.7 MKMs from Rhea and at a Sun-Rhea-spacecraft, or phase, angle of 40°. The image scale is approximately 10 Km per pixel. Cassini will image this hemisphere of Rhea again in mid-January 2005 with an approx. 1 Km resolution".
(25 voti)
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Japetus-PIA06521_modest.jpgThe "dark side" of Japetus71 visiteCaption NASA originale: "This image shows the dark, leading hemisphere of the mysterious moon Iapetus. The dark area is the Cassini region, named for Giovanni Cassini, who discovered the moon in 1672. The diameter of Iapetus is of approx. 1,436 Km (892 miles).
Cassini noted that he was able to see the moon on one side of its orbit around Saturn, but not on the other side. From this, he correctly deduced that one hemisphere must be dark while the other is much brighter".
(25 voti)
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Saturn-W00003105.jpgSaturn and his shadow (3)68 visite...tutte le nuove immagini che, per un motivo o per l'altro, potevano prestarsi a far sorgere nuove domande, nuovi dubbi, nuovi interrogativi - più o meno scabrosi - e che, comunque, potevano "imbarazzare" la National Aeronautics and Space Administration. Detto in un altro modo, stiamo parlando di "CENSURA". Però, come ben sapete, la NASA non gestisce questa Missione da sola: c'è di mezzo anche l'European Space Agency e l'Agenzia Spaziale Italiana. Leggete:
"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 Cassini-Huygens 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 team is based at the Space Science Institute, Boulder, Colo".
(25 voti)
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Craters-Balch_Crater-0.jpgMagellan Probe: radio image of Balch Crater137 visiteI risultati di tutte queste analisi e studi ci dicono che Venere NON mostra segni di attività tettonica (che sia almeno in parte assimilabile a quella esistente sulla Terra) in corso.
Oltre l'85% della superficie del Pianeta è ricoperta da uno strato di lava (o, comunque, da prodotti derivanti da eventi vulcanici) mentre il 15% residuo è costituito da cinture montuose altamente irregolari ("highly deformed mountain belts", si legge nel rapporto finale).
(25 voti)
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Craters-Fossey_Crater-PCF-LXTT-00.jpgMagellan Probe: radio image of Fossey Crater150 visiteNonostante l'elevata temperatura media superficiale (circa 475°C) e la pressione, anch'essa molto alta (in media 92 bars), la totale mancanza di acqua rende i processi erosivi estremamente lenti.
Ne consegue che le caratteristiche superficiali del Pianeta restano sostanzialmente inalterate per milioni di anni salva l'esistenza, in alcune zone, di curiose striature del terreno determinate, probabilmente, da venti (wind streaks) o da getti di materiale (polveri e massi) a seguito del verificarsi di impatti meteorici (dust streaks).
(25 voti)
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Atlas, Pandora and Janus-PIA06522_modest.jpgSaturn's Rings + Atlas, Pandora, Prometheus and Janus100 visiteCaption NASA originale: "Saturn hosts its own miniature solar system with an entourage of more than 30 moons. This image shows Saturn's "A" and "F" Rings, along with three of the moons that orbit close to them. From innermost to outermost, tiny Atlas (32 Km across) orbits just outside of the bright "A-Ring" and is seen above center in this view. Prometheus (102 Km across) is visible near lower right. Prometheus and its smaller cohort, Pandora, shepherd the thin, knotted F-Ring. Janus (181 Km across) can be seen near lower left. Janus shares its orbit with the moon Epimetheus. Density waves due to Janus cause some of the bright bands seen in the A-Ring in this image. Prometheus and Atlas also produce waves in the rings, but their wave regions are too narrow to be seen here. The planet's shadow stretches all the way across the main rings in this view. The shadow has an oval shape now but over the next few years it will become more rectangular as the planet orbits the Sun and the angle Sunlight-Rings decreases.
(20 voti)
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The Sun from Soho.jpgA "Solar Prominence" from Soho76 visiteCaption NASA originale:"A 'Solar Prominence' is a cloud of solar gas held above the Sun's surface by the Sun's magnetic field. The Earth would easily fit under the hovering curtain of hot gas (like the one pictured above). A quiescent prominence typically lasts about one month, and may erupt in a Coronal Mass Ejection (CME) expelling hot gas into the Solar System. Although somehow related to the Sun's changing magnetic field, the energy mechanism that creates and sustains a Solar Prominence is still a mistery".
(15 voti)
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Callisto-Chain of craters-PIA00514_modest.jpgA chain of craters on Callisto105 visiteCaption NASA originale:"A portion of a chain of impact craters on Jupiter's moon Callisto is seen in this image taken by the Galileo spacecraft on November 4, 1996. This crater chain on Callisto is believed to result from the impact of a split object, similar to the fragments of Comet Shoemaker-Levy 9 which smashed into Jupiter's atmosphere in July of 1994".
(15 voti)
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The Sun in Hydrogen-Alpha light.jpgThe Sun in "Hydrogen-alpha" light110 visiteCaption NASA originale:"The above picture was taken in a specific color of light emitted by Hydrogen gas called Hydrogen-alpha. Granules cover the solar photosphere surface like shag carpet, interrupted by bright regions containing dark sunspots. Our Sun glows because it is hot, but it is NOT on fire. Fire is the rapid acquisition of oxygen, and there is VERY LITTLE O2 on the Sun! The energy source of the Sun is the nuclear fusion of Hydrogen into Helium (4H--->1He) deep within its core".
(15 voti)
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Rhea from approx. 6.077.000 Km.jpgRhea from approx. 6.077.584 Km64 visitenessun commento
(15 voti)
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