| Risultati della ricerca nelle immagini - "Solar" |
0-SMART-1.jpgSMART-1 and the Moon93 visiteThe solar electric primary propulsion on-board SMART-1 is a Stationary Plasma Hall-effect thruster, the PPS-1350 developed by SNECMA, France. Using Xenon gas as propellant and the power from the spacecraft's solar arrays, the thruster is capable of providing a thrust of something like 70 milliNewtons. Using the thrust of the electric propulsion system, SMART-1 progressively expanded its orbit, spiralling out from Earth and was caught by the Moon's gravitational field on 15 November 2004, nearly 14 months after launch. In order to enhance the capture opportunities and to save precious fuel, SMART-1 also made use of celestial mechanics, including Moon resonances and swing-bys. The spacecraft exploited the unstable regions of space where the gravity field of Earth and Moon compete and which are normally avoided by conventional trajectories. It passed through the L1 point of the Earth-Moon System which allowed for the spacecraft to be caught by the Moon's gravity.
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00-SMART1.jpgSMART-1 and the Moon80 visiteSMART-1's science payload, with a total mass of some 15 Kg, features many innovative instruments and advanced technologies. These are:
- AMIE, a miniaturised HR camera for Lunar Surface imaging;
- SIR, a Near-Infrared Point-Spectrometer for Lunar mineralogy investigation;
- D-CIXS, a very compact X-ray Spectrometer with a new type of detector and micro-collimator which will provide fluorescence spectroscopy and imagery of the Moon's surface elemental composition;
- XSM, an X-ray monitor to support D-CIXS by providing measurements of solar X-ray emission for calibration:
- KaTE, an experiment aimed at demonstrating deep-space telemetry and telecommand communications in the X and Ka-bands;
- RSIS, a Radio-Science Experiment relying on KaTE. It monitors the electric propulsion by means of tracking techniques. In lunar orbit it will, with AMIE, also study the Moon's libration.
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000-0-Mars.jpgMeteor strike on Mars112 visiteMars may have lost much of its atmosphere during asteroid impacts early in its history.
The Beagle 2 lander will look for signatures of life on Mars, whether long-dead or still-living, by measuring the ratio of two different types of carbon in the rocks. Biological processes on Earth favour the lighter isotope of carbon, carbon-12, over the heavier carbon-13. Hence, a high carbon-12 to carbon-13 ratio is taken as evidence of life and has been found in rocks up to 4 billion years old, even where geological processing has occurred. The hope is that the same occurred on Mars.
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030-OPP-SOL209.jpgOver the Walls of Endurance (1)...66 visiteIpotesi di alba Marziana con il Sole capace di esprimere la stessa luminosità che è percepibile dalla Terra.
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032-OPP-SOL209.jpgOver the Walls of Endurance... (2)75 visiteImmagine in cui il Sole, ora, esprime un terzo in meno della luminosità percepibile dalla Terra. Notate una differenza?
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A-The Sun from Spitzer - spicules_sst_big.jpgSun "Spicules" from the Sptizer Space Telescope (SST)136 visiteCaption NASA originale: "Pictured above is perhaps the highest resolution image yet of the enigmatic "Solar Flux Tubes" known as "Spicules". Spicules dot the above frame of solar active region, but they are particularly evident as a carpet of dark tubes on the right. Time-sequenced images have recently shown that spicules "Life-span" is of about 5 minutes, starting out as tall tubes of rapidly rising gas but eventually fading as the gas peaks and falls back down to the Sun".
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Asbolus.jpg8405 Asbolus129 visiteThis is an artist's impression of object called 8405 Asbolus: a 48-mile-wide (about 80 Km) chunk of ice and dust that lies between Saturn and Uranus. Astronomers using NASA's HST were surprised to find that one side of the object (also called a "Centaur") looks like it has a fresh crater less than 10 MY old, exposing bright underlying ice. Actually, Hubble didn't directly see the Crater - the object is too small and far away - but a measure of its Surface Composition shows a complex chemistry that could be explained by the presence of a huge Impact Crater. The event that caused the Impact Crater on 8405 Asbolus may be the same one that knocked it out of the Kuiper's Belt (which is a "Ring of Comet Nuclei" located just beyond Pluto's orbit).
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AuroraBorealis-Alaska.jpgAurora over Alaska59 visiteCaption NASA:"Higher than the highest mountain, higher than the highest airplane, lies the realm of the aurora. Aurora rarely reach below 60 Km, and can range up to 1000. Aurora light results from solar shockwave causing energetic electrons and protons to striking molecules in the Earth's atmosphere. Frequently, when viewed from space, a complete aurora will appear as a circle around one of the Earth's magnetic poles. The above digitally enhanced photograph was taken in 2005 January shows a spectacular aurora borealis above the frozen landscape of Bear Lake, Alaska, USA.
The above image was voted Wikipedia Commons Picture of the Year for 2006".
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Chasma Boreale-00.JPGChasma Boreale (1)57 visiteBoth Martian Polar Caps show ragged outlines, with sinuous valleys and spiral-shaped troughs giving the Caps' edges a sawtooth outline. Scientists think the spirals develop as solar heating melts and evaporates the ice more strongly on the Equator-ward and West-facing sides of any slight depression. In time, these deepen into valleys and canyons.
The largest trough in the Northern Polar Cap is a huge canyon named Chasma Boreale. It runs into the ice cap for 570 Km (about 350 miles), making a broad valley that ends at a point called Tenuis Cavus, shown in this THEMIS image taken at visible wavelengths.
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Chasma Boreale-01.JPGChasma Boreale (2)57 visiteTapering from a width of 120 Km (75 miles) at its mouth, Chasma Boreale is only about 35 Km (22 miles) wide here. The cliffs on the Northern (top) and Eastern (right) sides of the image rise about 1400 meters (4600 feet) above the base. On the inside walls of this gigantic amphitheater are stacked layers of ice, while on its floor lie a dark sheet of what is likely frozen sand and a horde of sand dunes marching down-canyon under the winds' direction.
Chasma Boreale is so dramatic a feature that it forms part of a proposed martian "Polar Park." Yet setting aside future tourist revenues, the canyon is rewarding scientists today with glimpses into the history of the martian climate.
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ColdSpringtime.jpgCold Spring (by Roberto Tremolada)113 visitenessun commentoMareKromium
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Colourful_Earth.jpgEarth, from Monochrome to Polychrome (by Roberto Tremolada)55 visitenessun commentoMareKromium
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