| Risultati della ricerca nelle immagini - "Visions" |
AU Microscopii-02.jpgAU Microscopii and Circumstellar Debris Disk82 visite"...Real books should be the offspring not of daylight and casual talk, but of Darkness and Silence..."
Marcel Proust (1871-1922) - Le Temps Retrouvé
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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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Beta Pictoris-2.jpgBeta Pictoris114 visite"...Roman Virgil, thou that singest
Ilion's lofty temples robed in fire,
Ilion falling, Rome arising,
Wars, and filial faith, and Dido's pyre..."
Alfred, Lord Tennyson (1809-1892) - "To Virgil" (1882)
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Binary Brown Dwarf System-2.jpgBinary "Brown Dwarf" System71 visite"...Ingenium mala saepe movent..."
(Ovidio)
"...Sovente sono le difficoltà a spingere l'inventiva..."
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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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CollidingGalaxies-PIA02180_modest.jpgHearts of Glass110 visiteThis artist's concept shows delicate greenish crystals sprinkled throughout the violent core of a pair of colliding galaxies. The white spots represent a thriving population of stars of all sizes and ages. NASA's Spitzer Space Telescope detected more than 20 bright and dusty galactic mergers like the one depicted here, all teeming with the tiny gem-like crystals.
When galaxies collide, they trigger the birth of large numbers of massive stars. Astronomers believe these blazing hot stars act like furnaces to produce silicate crystals in the same way that glass is made from sand. The stars probably shed the crystals as they age, and as they blow apart in supernovae explosions.
At the same time the crystals are being churned out, they are also being destroyed. Fast-moving particles from supernova blasts easily convert silicates crystals back to their amorphous, or shapeless, form.
How is Spitzer seeing the crystals if they are rapidly disappearing? Astronomers say that, for a short period of time at the beginning of galactic mergers, massive stars might be producing silicate crystals faster than they are eliminating them. When our own galaxy merges with the Andromeda galaxy in a few billion years, a similar burst of massive stars and silicate crystals might occur.
Crystal Storm in Distant Galaxy
The graph (see inset above) of infrared data from NASA's Spitzer Space Telescope tells astronomers that a distant galaxy called IRAS 08752+3915 is experiencing a storm of tiny crystals made up of silicates. The crystals are similar to the glass-like grains of sand found on Earth's many beaches.
The data were taken by Spitzer's infrared spectrograph, which splits light open to reveal its rainbow-like components. The resulting spectrum shown here reveals the signatures of both crystalline (green) and non-crystalline (brown) silicates.
Spitzer detected the same crystals in 20 additional galaxies, all belonging to a class called ultraluminous infrared galaxies. These extremely bright and dusty galaxies usually consist of two galaxies in the process of smashing into each other. Astronomers believe massive stars at the hearts of the galaxies are churning out clouds of silicate crystals. This phenomenon may represent a short-lived phase in the evolution of galactic mergers.
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Earth From Mars.jpgMy "Day", your "Night"104 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.
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Echus_Chasma-398-260508-2204-6-co-01-H2.jpgHigh Cliffs Surrounding Echus Chasma on Mars60 visiteWhat created this great cliff on Mars? Did giant waterfalls once plummet through its grooves? With a four-kilometer drop, this high cliff surrounding Echus Chasma, near an impressive impact crater, was carved by either water or lava. A leading hypothesis is that Echus Chasma, at 100-Km long and 10-Km wide, was once one of the largest water sources on Mars. If true, water once held in Echus Chasma likely ran over the Martian Surface to carve the impressive Kasei Valles, which extends over 3000 Km to the North. Even if initially carved by water, lava appears to have later flowed in the valley, leaving an extraordinarily smooth floor. Echus Chasma lies north of tremendous Valles Marineris, the largest canyon in the Solar System. The above image was taken by the robotic Mars Express spacecraft currently orbiting Mars.
Nota Lunexit: checchè ne dica la NASA, questo frame NON E' una fotografia.MareKromium
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Enceladus~2.jpgEnceladian Geysers105 visiteDa "NASA - Picture of the Day" dell'8 Giugno 2006:"In this stunning Saturnian vista - one in a series of artist's visions of volcanos on alien worlds - icy geysers erupt along narrow fractures in inner moon Enceladus. The majestic plumes were actually discovered by instruments on the Cassini Spacecraft during close encounters with bright and shiny Enceladus last year. Researchers now suspect the plumes originate from near-surface pockets of liquid water with temperatures near 273 kelvins (0° Celsius) - hot when compared to the distant moon's surface temperature of 73 kelvins (- 200° C). A dramatic sign that tiny, 500km-diameter Enceladus is surprisingly active, these ice volcanos hold out another potential site in the search for water and origin of life beyond planet Earth.
Enceladus' ice volcanos also likely produce Saturn's faint but extended E-Ring".
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Extreme Planets-PIA08042_modest.jpgDeep Space...90 visite"...Tristis eris si solus eris..."
(Ovidio)
"...Sarai triste se sarai solo..."
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Fantasy APOD.jpgThe Universe is "on sight"!81 visiteDa "NASA - Picture of the Day" del 16 Giugno 2006:"The first APOD appeared 11 years ago today, on 1995, June 16. Although garnering only 14 page views on that day, we are proud to estimate that APOD has now served over 400 million space-related images over the last 11 years. That early beginning, along with a nearly unchanging format, has allowed APOD to be a consistent and familiar site on a web frequently filled with change. Many people don't know, though, that APOD is now translated daily into many major languages. We again thank our readers and NASA for their continued support, but ask that any potentially congratulatory e-mail go to the folks who created the great pictures - many times with considerable effort - that APOD has been fortunate enough to feature over the past year. Many can be contacted by following links found in the credit line under the image. Some of these images are featured in the above spectacular collage of a fantasy sky above Mars submitted by an enthusiastic APOD reader skilled in digital image manipulation. How many APOD images can you identify?".
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