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Asteroids-3753-Cruithne-1.gifAsteroid 3753 Cruithne - Horseshoe orbit of Cruithne from the Earth's perspective (Credits: Wikipedia)130 visitenessun commentoMareKromium
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Asteroids-3753-Cruithne-2.gifAsteroid 3753 Cruithne - Orbits of Cruithne and Earth (Credits: Wikipedia)114 visitenessun commentoMareKromium
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Asteroids-469219-Kamo_oalewa-1.jpgKamo'oalewa115 visiteKamo'oalewa è un piccolo asteroide che viaggia insieme alla Terra intorno al Sole e che potremmo considerare il nostro secondo satellite naturale insieme alla Luna.
Misura poco più di un campo da basket ed è molto probabile che la sua origine sia proprio la Luna, ovvero potrebbe essersi staccato in tempi antichi, rimanendo intrappolato parzialmente tra la forza di gravità terrestre e quella solare. Il suo nome in hawaiano significa "corpo celeste che oscilla" ed è stato scoperto il 27 aprile 2016 proprio grazie al telescopio PAN-STARRS che si trova alle Hawaii. Riguardo alla sua origine lunare è una teoria di cui si è parlato molto ultimamente e che è stata formulata in seguito allo studio del suo spettro luminoso che per molti anni è stato un mistero e che solo recentemente è stato confrontato con (quello emesso da) rocce raccolte (ovviamente sulla Luna) durante le missioni Apollo.
Gli astronomi notano che gli asteroidi vicini alla Terra 2020 PN1, 2020 PP1 e 2020 KZ2 hanno tutti orbite molto simili a Kamo'oalewa, quindi potrebbero provenire dallo stesso evento di impatto lunare o potrebbero anche aver fatto parte di un corpo comune che poi si è ulteriormente spaccato.
Adesso l'Agenzia Spaziale Cinese sta progettando una missione robotica per raggiungerlo e raccogliere dei campioni dalla sua superficie. La missione dovrebbe chiamarsi ZhengHe e, secondo indiscrezioni, dovrebbe partire nel 2024 (o nel 2025). MareKromium
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Asteroids-469219-Kamo_oalewa-2.jpgKamo'oalewa110 visiteThe size of Kamo'oalewa has not yet been firmly established, but it is likely that it is approximately 40-to-100 meters (130–330 feet).Based on an assumed standard albedo for stony S-type asteroids of 0.20 and an absolute magnitude of 24.3, it measures 41 meters (135 ft) in diameter. Photometric observations in April 2017 revealed that Kamoʻoalewa is a fast rotator. Lightcurve analysis gave a rotation period of 0.467 ± 0.008 hours (28.02 ± 0.48 minutes) and a brightness variation of 0.80±0.05 magnitude (U=2). In 2021, a comprehensive physical characterization of Kamoʻoalewa was conducted using the Large Binocular Telescope and the Lowell Discovery Telescope, which found that the asteroid is composed of lunar-like silicates and may be an impact fragment from the Moon.
During the 2017 Astrodynamics Specialist Conference held in Stevenson in the U.S. state of Washington, a team composed of graduate research assistants from the University of Colorado Boulder and the São Paulo State University (UNESP) was awarded for presenting a project denominated "Near-Earth Asteroid Characterization and Observation (NEACO) Mission to Asteroid (469219) 2016 HO3", providing the first baselines for the investigation of this celestial object using a spacecraft. Recently, another version of this work was presented adopting different constraints in the dynamics.
The China National Space Administration (CNSA) is planning a robotic mission that would return samples from Kamoʻoalewa. Currently, this mission, via ZhengHe, is planned to launch in 2025.MareKromium
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Asteroids-Annefrank_Asteroid-PIA02885_modest.jpgAsteroid Annefrank from Stardust86 visiteAsteroid Annefrank is seen as irregularly shaped, cratered body in an image taken by NASA's Stardust spacecraft during a Nov. 2 flyby of the asteroid.
Stardust flew within about 3.300 Km (about 2.050 miles) of the asteroid as a rehearsal for the spacecraft's encounter with its primary target, comet Wild 2, in January 2004. The camera's resolution was sufficient to show that Annefrank is about 8 Km (5 miles) in length, twice the predicted size from Earth-based observations. The surface reflects about 0,1 to 0,2% of sunlight, slightly less than anticipated. A few craters that are hundreds of meters across can be seen. The straight edge in the right side of the image may be an artifact of processing.
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Asteroids-Asteroid_1994-CC-PIA12134.gifTriple Asteroid 1994-CC in motion (GIF-Movie; credits: NASA/JPL/GSSR)73 visiteCaption NASA:"Radar imaging at NASA's Goldstone Solar System Radar on June 12 and 14, 2009, revealed that near-Earth Asteroid 1994-CC is a Triple System.
Asteroid 1994 CC encountered Earth within 2,52 MKM (such as 1,56 MMs) on June 10. Prior to the flyby, very little was known about this celestial body. 1994 CC is only the second Triple System known in the near-Earth population. A team led by Marina Brozovic and Lance Benner, both scientists at NASA's Jet Propulsion Laboratory in Pasadena, Calif., made the discovery.
1994-CC consists of a central object about 700 meters (2300 feet) in diameter that has two smaller moons revolving around it. Preliminary analysis suggests that the two small satellites are at least 50 meters (164 feet) in diameter.
Radar observations at Arecibo Observatory in Puerto Rico, led by the center's director Mike Nolan, also detected all 3 objects, and the combined observations from Goldstone and Arecibo will be utilized by JPL scientists and their colleagues to study 1994-CC's orbital and physical properties.
The next comparable Earth flyby for Asteroid 1994-CC will occur in the year 2074 when the space rock trio flies past Earth at a distance of about 2,5 MKM (such as approx. 1,6 million miles). Of the hundreds of near-Earth asteroids observed by radar, only about 1% are Triple Systems".MareKromium
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Asteroids-Asteroid_1994-CC-PIA12134.jpgTriple Asteroid 1994-CC77 visitenessun commentoMareKromium
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Asteroids-Asteroid_2002JF56-PIA09230-00.jpgUnknown Asteroid64 visiteUn'immagine non particolarmente suggestiva, ma comunque importante, molto importante: ci arriva dalla Sonda New Horizons che sta calibrando le proprie fotocamere, in attesa (una LUNGA attesa...) di giungere nello Spazio di Plutone e quindi nella Fascia di Kuiper, tra il 2015 ed il 2020...
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Asteroids-Asteroid_2002JF56-PIA09230-01.jpgFormer "Unknown Asteroid" is now "Asteroid 2002 JF56"67 visiteThe two "spots" in this image are a composite of two images of asteroid 2002 JF56 taken on June 11 and June 12, 2006, with the Multispectral Visible Imaging Camera (MVIC) component of the New Horizons Ralph imager. In the bottom image, taken when the asteroid was about 3,36 MKM (approx. 2,1 MMs) away from the Spacecraft, 2002 JF56 appears like a dim star. At top, taken at a distance of about 1,34 MKM (such as about 833.000 miles), the object is more than a factor of six brighter.
The best current, estimated diameter of the asteroid is approx. 2,5 Km.
The asteroid observation was a chance for the New Horizons team to test the spacecraft's ability to track a rapidly moving object. On June 13 New Horizons came to within about 102.000 Km of the small asteroid, when the Spacecraft was nearly 368 MKM (about 228 MMs) from the Sun and about 273 MKM (approx 170 MMs) from Earth.MareKromium
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Asteroids-Asteroid_2007-TU24.jpgAsteroid 2007 TU24 (Radar View)86 visiteAsteroid 2007 TU24 passed by the Earth yesterday, posing no danger. The space rock, estimated to be about 250 mt across, coasted by just outside the orbit of Earth's Moon. The passing was not very unusual - small rocks strike Earth daily, and in 2003 a rock the size of a bus passed inside the orbit of the Moon, being detected only after passing. TU24 was notable partly because it was so large. Were TU24 to have struck land, it might have caused a magnitude 7 earthquake and left a city-sized crater. A perhaps larger danger would have occurred were TU24 to have struck the ocean and raised a large tsunami.
This radar image was taken 2 days ago. The Arecibo Radio Telescope in Puerto Rico broadcast radar that was reflected by the asteroid and then recorded by the Byrd Radio Telescope in Green Bank, West Virginia. The resulting image shows TU24 to have an oblong and irregular shape. TU24 was discovered only three months ago, indicating that other potentially hazardous asteroids might lurk in our Solar System currently undetected. Objects like TU24 are hard to detect because they are so faint and move so fast. Humanity's ability to scan the sky to detect, catalog, and analyze such objects has increased notably in recent years.
MareKromium
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Asteroids-Hygiea.jpgAsteroid 10 Hygiea112 visiteGrazie al lavoro della "Two Micron All Sky Survey - 2MASS" siamo in grado di offrirvi le immagini di qualche asteroide del tutto sconosciuto (crediamo) a coloro che non siano - in qualche modo - direttamente "addetti ai lavori" nei Campi dell'Astronomia e/o dell'Astrofisica (Studenti delle due Discipline inclusi).
Si tratta di immagini che non ci dicono molto, dal punto di vista di un eventuale studio delle caratteristiche superficiali di questi oggetti (a dire il vero una cosa sembrano dirla: si tratta di oggetti davvero molto luminosi!), ma che, in ogni caso, rimangono molto suggestive e sono capaci di mostrarci dei "frammenti" di Cielo che contengono, oltre ai cosiddetti "corpi fissi" (cioè stelle e galassie), anche degli oggetti "mutevoli e transitori" (almeno dal punto di vista di chi li osserva).
Gli Asteroidi, appunto.
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Asteroids-Opportunity-041007163946.jpgThe path to immortality: an asteroid named "Opportunity"67 visiteL'immortalità (o quasi), in qualche modo, le Sonde Spirit ed Opportunity sono riuscite a guadagnarsela: il lavoro svolto dai due Rover, infatti, è stato (ed è tuttora) così prezioso e scientificamente significativo che si è pensato - ed è la prima volta in assoluto che accade una cosa simile - di dedicare ai due robot (e NON, quindi, ad un "essere umano"...) due asteroidi scoperti all'inizio degli anni '60, ma definitivamente riconosciuti e codificati - mediante l'assegnazione di un numero seriale ufficiale - solo nel 2002 (in questo caso, però, non si è trattato di inefficienza, bensì di ottemperanza alle rigide regole stabilite dalla IAU - International Astronomical Union - le quali "...require asteroids to be observed during 4 separate cycles around the Earth and Sun before they become eligible for numbering and naming...").
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