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| Risultati della ricerca nelle immagini - "Asteroid" |
0-433-EROS-01.gif433 Eros (GIF-Movie; credits: Dr G. Barca)97 visiteIn questi giorni, dopo anni di silenzio, abbiamo parlato del bizzarro (se non altro nelle sue forme...) asteroide noto come 433-Eros.
Sono bastate poche, ma ragionate, parole ed immagini per capire quanta ignoranza e quanta disinformazione caratterizzi il nostro Mondo: il Mondo dei Ricercatori nel Campo delle Scienze Planetarie e delle Analisi su Fenomeni (cosiddetti) "di Confine".
La Missione NEAR-Shoemaker, quando si svolse (sostanzialmente nel silenzio dei media - come sempre...), ci lasciò affascinati e sorpresi.
Affascinati, perchè l'Universo "affascina", per definizione.
Sopresi, perchè per noi, Anomaly Hunters, l'asteroide 433-Eros sembrò rivelarsi - ictu oculi - come una "fucina di Anomalìe".
Ma il tempo passa: si cresce, ci si sviluppa, si migliora (di solito ed auspicabilmente, almeno). E con il passare del tempo, il nostro entusiasmo - relativo alle Anomalìe di 433-Eros - si è spento.
Si è spento perchè, di "Anomalìe VERE", su quell'Asteroide, siamo arrivati a verificare - e quindi a convincerci razionalmente - che non ce ne sono.
Ma non tutti la pensano come noi. E questo è giusto.
Che fare, allora? Semplice: essendo la nostra Associazione una Associazione che ha per fine, in fondo, la Divulgazione del Sapere, abbiamo deciso di creare un Album il quale fosse integralmente dedicato a questo Asteroide e che contenesse - come da titolo - "le immagini, i fatti e le leggende".
In quello che vedrete e leggerete non c'è pretesa di Verità Assoluta, questo è evidente, ma non c'è neppure l'arroganza di dire "le cose stanno così, e chi non crede a quello che diciamo noi, o è un incompetente o un idiota". Tertium non datur.
Questo Album è dedicato, oltre che all'asteroide 433-Eros, a TUTTI coloro che coltivano la Pianta del Sapere, agendo nella quieta consapevolezza che il Giardino in cui essa "cresce" è di tutti, e nella certezza che la capacità di trarre nutrimento e giovamento dai suoi "frutti" (qualora ne nascano) è tuttavia un fatto assolutamente personale e dagli effetti imprevedibili...MareKromium
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0-AS17-Metric-FNB2444.jpgElements of Exo-Geology: Notion and Definition53 visiteL'Eso-Geologia (detta anche Geologia Planetaria, o Astrogeologia) è la Disciplina che studia la Geologia dei Corpi Celesti extra-terrestri: i Pianeti del Sistema Solare e le loro lune, gli Asteroidi, le Comete e, quando è possibile, i Meteoriti.
Fu il grande Dr Eugene Shoemaker ad introdurre questa Disciplina nel Servizio Geologico degli Stati Uniti (USGS) e fu grazie a lui che vennero apportati dei numerosi (e validi) contributi allo studio dei crateri di impatto (Terrestri ed extra-terrestri), della Luna e di alcuni Asteroidi e Comete.
L'Eso-Geologia, nella sua veste operativa, utilizza le Tecniche della Geomorfologia e, in particolare, del Telerilevamento per studiare e caratterizzare la superficie dei Corpi Celesti.
Lo studio - prevalentemente teorico - dei loro strati più interni è invece basato su metodi Fisici o Astronomici (anche se oggi, grazie alle nuove tecnologie che sono a disposizione, è già possibile studiare la struttura e la composizione degli strati interni di alcuni Corpi Celesti - pensate, ad esempio, al Lavoro svolto per Marte dal Radar "MARSIS" il quale si trova a bordo della Sonda ESA "Mars Express").
Ciò premesso, diciamo che a cominciare da oggi, 10 Luglio 2008, agendo nel quadro delle attività Divulgative ed Istituzionali proprie dell'Associazione Lunar Explorer Italia, abbiamo deciso che proveremo - avvalendoci del prezioso contributo del nostro Socio ed Amico, il Dr Gualtiero La Fratta (Geologo) - a darVi qualche Elemento Tecnico Essenziale relativo a questa affascinante Disciplina il quale, auspicabilmente, possa permettere a coloro che ci leggono di apprendere qualcosa in più circa la Natura e la Struttura, esterna ed interna, dei Mondi che, da anni, cerchiamo di esplorare "a tavolino".
Buon Viaggio, quindi, e Grazie a TUTTI per l'essere ancora con noi!MareKromium
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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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000-Ceres~0.jpgBig Asteroid or Small Planet?65 visiteLa decisione non è stata ancora presa, ma il problema rimane: 1-Cerere è un "grande" Asteroide o un "piccolo" Pianeta?
A parte tutto, Cerere sembra proprio essere un mondo a sè: le sue dimensioni (circa 930 Km di iametro) sono modeste ma, per un asteroide, alquanto consistenti (Cerere è comunque l'oggetto conosciuto più grande fra le (decine di) migliaia che si trovano in quella regione di spazio compresa fra le orbite di Marte e Giove e che è comunemente conosciuta come "Cintura degli Asteroidi" (o Asteroids' Belt).
Di 1-Cerere si parla molto in questi giorni perchè la IAU (International Astronomical Union) sta valutando se conferire a questo Corpo Celeste lo "status" di Pianeta vero e proprio oppure no, ma la NASA - a quanto si sa - era già da tempo interessata a questo piccolo mondo ed infatti, proprio in questi giorni, è in fase di completamento la preparazione della Sonda "Dawn" (alba) la quale verrà lanciata nel 2007 (forse a Giugno) e che dovrebbe raggiungere e studiare MOLTO da vicino l'asteroide Vesta (nel 2011) e - guarda caso... - proprio 1-Cerere, nel 2015 (l'Anno del possibile - ed auspicabile - "contatto" fra l'altra Sonda New Horizons ed il Doppio Pianeta - o Sistema Binario formato da - Plutone e Caronte.
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000-Clementine.gif000 - Clementine56 visiteDescription
Clementine was a joint project between the Ballistic Missile Defense Organization (BMDO, nee the Strategic Defense Initiative Organization, or SDIO) and NASA. The objective of the mission was to test sensors and spacecraft components under extended exposure to the space environment and to make scientific observations of the Moon and the near-Earth asteroid 1620 Geographos. The Geographos observations were not made due to a malfunction in the spacecraft. The lunar observations made included imaging at various wavelengths in the visible as well as in ultraviolet and infrared, laser ranging altimetry, gravimetry, and charged particle measurements. These observations were for the purposes of obtaining multi-spectral imaging the entire lunar surface, assessing the surface mineralogy of the Moon and obtaining altimetry from 60N to 60S latitude and gravity data for the near side. There were also plans to image and determine the size, shape, rotational characteristics, surface properties, and cratering statistics of Geographos. Clementine carried 7 distinct experiments on-board: a UV/Visible Camera, a Near Infrared Camera, a Long Wavelength Infrared Camera, a High Resolution Camera, two Star Tracker Cameras, a Laser Altimeter, and a Charged Particle Telescope. The S-band transmitter was used for communications, tracking, and the gravimetry experiment.
Spacecraft and Subsystems
The spacecraft was an octagonal prism 1.88 meters high and 1.14 m across with two solar panels protruding on opposite sides parallel to the axis of the prism. A high-gain fixed dish antenna was at one end of the prism, and the 489 N thruster at the other end. The sensor openings were all located together on one of the eight panels, 90 degrees from the solar panels, and protected in flight by a single sensor cover. The spacecraft propulsion system consisted of a nonpropellant hydrazine system for attitude control and a bipropellant nitrogen tetraoxide and monomethyl hydrazine system for the maneuvers in space. The bipropellant system had a total capability of about 1900 m/s with about 550 m/s required for lunar insertion and 540 m/s for lunar departure. Attitude control was achieved with 12 small attitude control jets, two star tracker cameras, and two inertial measurement units. The spacecraft was three-axis stabilized in lunar orbit via reaction wheels with a precision of 0.05 Deg. in control and 0.03 Deg. in knowledge. Power was provided by gimbaled, single axis, GaAs/Ge solar panels which charged a 15 amp-hour, 47-w hr/Kg Nihau (Ni-H) common pressure vessel battery. Spacecraft data processing was performed using a MIL-STD-1750A computer (1.7 million instructions per second) for savemode, attitude control, and housekeeping operations, a RISC 32-bit processor (18 million ips) for image processing and autonomous operations, and an image compression system provided by the French Space Agency CNES. A data handling unit sequenced the cameras, operated the image compression system, and directed the data flow. Data was stored in a 2 Gbit dynamic solid state data recorder.
Mission Profile
The mission had two phases. After two Earth flybys, lunar insertion was achieved approximately one month after launch. Lunar mapping took place over approximately two months, in two parts. The first part consisted of a five hour elliptical polar orbit with a periapsis of about 400 Km at 30 degrees south latitude and an apoapsis of 8300 Km. Each orbit consisted of an 80 minute lunar mapping phase near periapsis and 139 minutes of downlink at apoapsis. After one month of mapping the orbit was rotated to a periapsis at 30 degrees north latitude, where it remained for one more month. This allowed global imaging and altimetry coverage from 60 degrees south to 60 degrees north, over a total of 300 orbits. After a lunar/Earth transfer and two more Earth flybys, the spacecraft was to head for Geographos, arriving three months later for a flyby, with a nominal approach closer than 100 Km. Unfortunately, on May 7, 1994, after the first Earth transfer orbit, a malfunction aboard the craft caused one of the attitude control thrusters to fire for 11 minutes, using up its fuel supply and causing Clementine to spin at 80 rpm. Under these conditions, the asteroid flyby could not yield useful results, so the spacecraft was put into a geocentric orbit passing through the Van Allen radiation belts to test the various components on board. The mission ended in June 1994 when the power level onboard dropped to a point where the telemetry from the spacecraft was no longer intelligible.
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001-Ceres-alone.jpg1-Ceres from Hubble Space Telescope58 visiteNASA's Hubble Space Telescope took these images of the asteroid 1 Ceres over a 2-hour and 20-minute span, the time it takes the Texas-sized object to complete one quarter of a rotation. One day on Ceres lasts 9 hours.
Hubble snapped 267 images of Ceres as it watched the asteroid make more than one rotation. By observing the asteroid during a full rotation, astronomers confirmed that Ceres has a nearly round body like Earth's. Ceres' shape suggests that its interior is layered like those of terrestrial planets such as Earth. Ceres may have a rocky inner core, an icy mantle, and a thim, dusty, outer crust.
The "Bright Spot" that we see is a mistery: it is (obviously) brighter than its surroundings, but it is still very dark (very low albedo) reflecting only a small portion of Sunlight.
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004-Ceres.jpgMoments of 1-Ceres (1)53 visiteDa "NASA - Picture of the Day", del 21 Agosto 2006:"Is 1-Ceres an Asteroid or a Planet?
Although a trivial designation to some, the recent suggestion by the Planet Definition Committee of the International Astronomical Union would have 1-Ceres reclassified from Asteroid to Planet.
A change in taxonomy might lead to more notoriety for the frequently overlooked world. Ceres, at about 1000 Km across, is the largest object in the main Asteroid Belt between Mars and Jupiter. Under the newly proposed criteria, Ceres would qualify as a planet because it is nearly spherical and sufficiently distant from other planets. Pictured above is the best picture yet of Ceres, taken by the Hubble Space Telescope as part of a series of exposures ending in 2004 January. Currently, NASA's Dawn mission is scheduled to launch in 2007 June to explore Ceres and Vesta, regardless of their future designations".
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005-Ceres.jpgMoments of 1-Ceres (2)53 visiteFor 2 centuries it was the largest known rock in the Solar System. The Texas-sized asteroid Ceres, about 930 Km (about 580 miles) across, was the first asteroid ever detected. The space rock was identified in 1801 by astronomer Giuseppe Piazzi, a monk in Sicily and the founding director of the Palermo Astronomical Observatory. He noted over a few nights a shifting point in the sky that wasn't one of the planets, their moons or a star. Thus, he discovered the rock.
After discovering the asteroid, Piazzi was invited to join the Celestial Police, a group of 24 international astronomers looking for what they called "guest planets" between Mars and Jupiter. The Celestial Police noted that the spacing between planets was fairly regular, but that there was a large gap between Mars and Jupiter.
Soon other small bodies were discovered in that region (Pallas in 1802, Juno in 1804 and Vesta in 1807), so the Celestial Police concluded that not just one, but many minor planets had to exist in a Main Asteroid Belt.
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006-Ceres.jpg1-Ceres (natural colors, from HST - credits: NASA/ESA et al.)53 visiteThe Hubble image of Ceres on the reveals bright and dark regions on the asteroid's surface that could be topographic features, such as craters, and/or areas containing different surface material. Large impacts may have caused some of these features and potentially added new material to the landscape. The Texas-sized asteroid holds about 30 to 40% of the mass in the Asteroid Belt.
Ceres' round shape suggests that its interior is layered like those of terrestrial planets such as Earth. The asteroid may have a rocky inner core, an icy mantle, and a thin, dusty outer crust. The asteroid may even have water locked beneath its surface. It is approx. 590 miles (950 Km) across and was the first asteroid discovered in 1801.
The observation was made in visible and ultraviolet light between December 2003 and January 2004 with the HST Advanced Camera for Surveys. The color variations in the image show either a difference in texture or composition on Ceres' surface.
Astronomers need the close-up views of the Dawn spacecraft to determine the characteristics of these regional differences.
MareKromium
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007-Ceres-PIA10235.jpg1-Ceres (natural colors, from HST - credits: NASA/ESA et al.)53 visiteCaption NASA:"This is a NASA Hubble Space Telescope color image of 1-Ceres, the largest object in the Asteroid Belt.
Astronomers enhanced the sharpness in these Advanced Camera for Surveys images to bring out features on Ceres' surface, including brighter and darker regions that could be asteroid impact features.
The observations were made in Visible and UV Light between December 2003 and January 2004.
The colors represent the differences between relatively red and blue regions. These differences may simply be due to variation on the surface among different types of material.
Ceres' round shape suggests that its interior is layered like those of terrestrial planets such as Earth. Ceres may have a rocky inner core, an icy mantle, and a thin, dusty outer crust inferred from its density and rotation rate of 9 hours. Ceres is approximately 590 miles (about 950 Km) across and was first discovered in 1801".MareKromium
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008-Ceres-Dumas_300-PCF-LXTT.jpg1-Ceres from Keck Observatory102 visitenessun commentoMareKromium
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015-Ceres_and_Vesta.jpg4-Vesta and 1-Ceres from HST (natural colors)53 visiteThese Hubble Space Telescope images of Vesta and 1-Ceres show two of the most massive asteroids in the Asteroid Belt, a Region between Mars and Jupiter.
The images are helping astronomers plan for the Dawn spacecraft’s tour of these hefty asteroids. On July 7, 2007, NASA is scheduled to launch the spacecraft on a 4-year journey to the Asteroid Belt. Once there, Dawn will do some asteroid-hopping, going into orbit around Vesta in 2011 and Ceres in 2015. Dawn will be the first spacecraft to orbit two targets. At least 100.000 asteroids inhabit the Asteroid Belt, a reservoir of leftover material from the formation of our Solar-System planets some 4,6 Billion Years (BY) ago.MareKromium
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