| Piú votate - Asteroids and Comets |
Eros-NP-PIA02498.jpgThe North Pole of Eros58 visiteCaption NASA originale:"For a long time, imaging activities on the NEAR Shoemaker spacecraft have focused on the high northern latitudes of Eros. The point at which the Sun is directly overhead - known as the "subsolar point" - has been steadily moving from Eros' Northern Regions toward the equator as the asteroid's seasons progress. As this happens, the Northern Hemisphere is illuminated less and less and previously dark southern latitudes progressively come into view. In this image, taken March 19, 2000, from a range of 205 Km (approx. 127 miles), the asteroid's North Pole is in the upper right of the frame. The whole scene is 7,4 Km (approx. 4,6 miles) across".
(4 voti)
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Eros-NorHem-PIA02923.jpgThe Northern Hemisphere of Eros57 visiteCaption NASA originale:"This spectacular view - looking down on the North Polar Region of Asteroid Eros - was constructed from 6 images taken February 29, 2000, from an orbital altitude of about 200 Km (approx. 124 miles). This vantage point highlights the major physiographic features of the Northern Hemisphere: the saddle seen at the bottom; the 5,3-Km diameter crater at the top and a major ridge system running between the two features that spans at least one-third of the asteroid's circumference".
Note: this a mosaic of images 0127275100, 0127275164, 0127275246, 0127275310, 0127275456, 0127275520
(4 voti)
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Gaspra-Deimos-Phobos-PIA00078_modest.jpgGaspra, Deimos and Phobos57 visiteCaption NASA originale:"This montage shows asteroid 951 Gaspra (top) compared with Deimos (lower left) and Phobos (lower right), the moons of Mars. The three bodies are shown at the same scale and nearly the same lighting conditions. Gaspra is about 17 Km (10 miles) long. All three bodies have irregular shapes, due to past catastrophic conditions. However their surfaces appear remarkably different, possibly because of differences in composition but most likely because of very different impact histories. The Phobos and Deimos images were obtained by the Viking Orbiter spacecraft in 1977; the Gaspra image is the best of a series obtained by the Galileo spacecraft on October 29, 1991".
(4 voti)
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EROS-PIA02493_modest.jpgSunset on Eros58 visiteEros' irregular shape gives rise to some stunning vistas at the time of sunrise or sunset. On March 6, 2000, the imager on the NEAR Shoemaker spacecraft caught this view of a stunning sunset. In the pitch black foreground the Sun has already set, but just over the horizon another part of the asteroid remains lit. Eros' rotation period is just 5 hours, 16 minutes, so in the course one 24-hour Earth day an observer on Eros would be treated to four full cycles of sunrises and sunsets.
(4 voti)
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Eros from 120 mt - PIA03148_modest.jpgFalling down: Eros from 120 mt56 visiteCaption originale:"This is the last image of asteroid 433 Eros received from NEAR Shoemaker. Taken from a range of 120 meters, it measures 6 meters across. What we can see of the rock at the top of image measures 4 meters across. The streaky lines at the bottom indicate loss of signal as the spacecraft touched down on the asteroid during transmission of this image". La Sonda - probabilmente - si ribalta al momento del touch-down, il segnale si perde e la Missione termina per sempre. Sin qui l'ufficialità. Ufficiosamente, possiamo dirVi che la Sonda ha continuato a trasmettere dati ancora per molto tempo dopo l'impatto, ma su come abbia potuto farlo e di quali dati si trattasse, come potrete agevolmente intuire, non siamo riusciti a sapere assolutamente nulla. E' strano, però: la NASA avrebbe dovuto celebrare trionfalmente la sopravvivenza della Sonda NEAR all'impatto con l'asteroide, così come sta trionfalmente celebrando la sopravvivenza "oltre le più rosee aspettative" dei Mars Rovers, e invece...Silenzio.
(4 voti)
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Eros from 250 mt - PIA03147_modest.jpgFalling down: Eros from 250 mt66 visiteCaption NASA:"...The image is 12 meters across. The cluster of rocks at the upper right measures 1.4 meters across...". Vale quanto già detto in precedenza: riuscite a vedere dei dettagli già presenti nel frame precedente?!?
NEAR, scendendo, fotografa "random"?
(4 voti)
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Eros from 700 mt - PIA03146_modest.jpgFalling down: Eros from 700 mt57 visiteCaption NASA:"...The image is 33 meters across. The large, oblong rock casting a big shadow measures 7.4 meters across...".
Riuscite a distinguere in questo scorcio ulteriormente ravvicinato qualche dettaglio il quale - ora, ovviamente, ingrandito - fosse già presente nel frame precedente? Noi non ci siamo riusciti.
(4 voti)
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Eros from 1150 mt - PIA03145_modest.jpgFalling down: Eros from 1150 mt58 visiteIn sequenza, le ultime (?) 4 immagini ricevute sulla Terra e relative alla discesa della Sonda NEAR sull'asteroide Eros. Purtroppo non siamo in grado di operare delle valutazioni precise sul contenuto di questi frames i quali, per svariati ordini di motivi, NON ci convincono. I particolari della superficie di Eros variano da frame a frame (come se la Sonda stesse precipitando, seguendo una traiettoria non lineare), ma la qualità (in termini di definizione e nitidezza dei dettagli ripresi) dei singoli frames, invece, lascia supporre un landing morbido ed una discesa "smooth".
La NASA, inoltre, dice che "...The image is 54 meters across. The large rock at lower left is 7.4 meters across..." ma questi dati non sembrano totalmente convincenti.
Vediamo gli altri 3 frames...
(4 voti)
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EROS-PIA03129.jpgEros from above (2)66 visiteNEAR Shoemaker photographed this area of Eros on December 18, 2000, from an orbital altitude of 33 Km. This part of the asteroid's surface, like many others, appears vaguely "sculptured" due to its low, elongated ridges and depressions with seemingly consistent orientations. Some of the low spots also contain accumulations of smooth, pond-like materials. Neither the surface sculpturing nor the pond-like materials are well understood, and both will be investigated in detail using even higher-resolution images from NEAR Shoemaker's low passes over Eros in early 2001. The whole scene is about 1 Km across.
(4 voti)
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Dart-7.jpegDimorphos146 visiteDART's last complete image of Dimorphos before impact. It was taken when the spacecraft was about 7 miles (approx. 12 Km) from the asteroid and 2" before impact. Dimorphos was about 6,8 MMs (such as about 11 MKM) from Earth at the time of DART's impact.MareKromium
(3 voti)
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Didymos_and_Dimorphos.jpeg65803 Didymos and 65803-1 Dimorphos101 visiteAsteroid Didymos and its small moonlet Dimorphos make up what’s called a "Binary Asteroid System" – meaning the small moon (Dimorphos) orbits the larger body (Didymos).
The two asteroids are not a threat to Earth, but because they do pass relatively close to Earth, they were chosen as the target for NASA’s Double Asteroid Redirection Test (DART) mission – the agency's first mission to test planetary defense technology. This technology could one day be used to deflect hazardous asteroids on a collision course with Earth.MareKromium
(3 voti)
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Dart-6.jpgGreat Balls of Fire! - 680 visitenessun commentoMareKromium
(3 voti)
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