| Piú votate - Asteroids and Comets |
Tempel1-VV-nhvcaxf9000910-PIA02131.jpgImpact Time!58 visiteWhen NASA's Deep Impact probe collided with Tempel-1, a bright, small flash was created, which rapidly expanded above the surface of the comet. This flash lasted for more than a second and its overall brightness is close to that predicted by several models. After the initial flash, there was a pause before a bright plume quickly extended above the comet surface. The debris from the impact eventually cast a long shadow across the surface, indicating a narrow plume of ejected material, rather than a wide cone. The Deep Impact probe appears to have struck deep, before gases were heated and explosively released. The impact crater was observed to grow in size over time. A preliminary interpretation of these data indicate that the upper surface of the comet may be fluffy, or highly porous. The observed sequence of impact events is similar to laboratory experiments using highly porous targets, especially those that are rich in volatile substances. The duration of the hot, luminous gas phase, as well as the continued growth of the crater over time, all point to a model consistent with a large crater.
(6 voti)
|
|
Tempel1-W.jpgDeep-impact...13 seconds after collision!57 visiteCaption NASA originale:"This image shows the initial ejecta that resulted when NASA's Deep Impact probe collided with comet Tempel-1 at 10:52 p.m. Pacific Time, July 3 (1:52 a.m. Eastern time, July 4). It was taken by the spacecraft's high-resolution camera 13 seconds after impact. The image has been digitally processed to better show the comet's nucleus".
(6 voti)
|
|
Tempel1-S-ImpactConfirmation.jpgTempel-1 from Kitt Peak National Obs.58 visiteOriginal caption:"The image was taken through an R band filter and has the smoothed dust light profile removed to enhance the jets. North is up, East to the left, the Sun at PA (Position Angle) 290 and the FOV is 2,5 arcmin (which is now 96.500 km at the comet)".
T. Farnham and Jianyang Li
(University of Maryland)
(6 voti)
|
|
EROS-PIA02906_modest.jpgHorizon view58 visiteThis image of Eros, taken from the NEAR Shoemaker spacecraft on May 2, 2000, from an orbital altitude of 52 kilometers (32 miles), shows a view toward Eros' horizon. The section shown is about 1.8 kilometers (1.1 miles) across. This particular view provides a snapshot of three of the most common types of features seen on the asteroid: craters whose rims have been rounded by erosion due to smaller impacts and blanketing by the impact debris, or regolith (impact debris); variations in the brightness of material on the walls of the craters; and a scattering of boulders ranging in size from nearly 100 meters (328 feet) down to about 8 meters (26 feet).
(6 voti)
|
|
EROS-PIA02907_modest.jpgA strange drawing made by lights and shadows...61 visiteEros' irregular shape creates interesting and beautiful scenes where the Sun shines obliquely on the surface. In the absence of an atmosphere, and hence no secondary illumination reflecting from atmospheric molecules, shade appears nearly as black as space. This image, taken from the NEAR Shoemaker spacecraft on May 2, 2000, from an orbital altitude of 50 kilometers (31 miles), shows one of the more telling and yet comical combinations of light and shadow. The entire scene is about 1.8 kilometers (1.1 miles) across. High spots near the edges of shadows, like the 35-meter (115-foot) diameter boulder just below the center of the frame, seem almost to "float" above the surface. With a little imagination, the shadow dominating the right side of the frame could be seen as a small, long-eared terrier bending over to sniff his dinner!
(6 voti)
|
|
Asteroids-469219-Kamo_oalewa-1.jpgKamo'oalewa95 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
(5 voti)
|
|
Asteroids-3753-Cruithne-1.gifAsteroid 3753 Cruithne - Horseshoe orbit of Cruithne from the Earth's perspective (Credits: Wikipedia)112 visitenessun commentoMareKromium
(5 voti)
|
|
Asteroids-3753-Cruithne-0.jpgAsteroid 3753 Cruithne85 visiteLA "Seconda Luna della Terra".MareKromium
(5 voti)
|
|
Asteroids-3753-Cruithne-2.gifAsteroid 3753 Cruithne - Orbits of Cruithne and Earth (Credits: Wikipedia)106 visitenessun commentoMareKromium
(5 voti)
|
|
Comet_Borisov_-_GIF_3.gifFrom far away: the Comet Borisov through the Solar System (GIF-Movie)285 visiteGuardate bene! EccoVi la differenza (REALE ed IN FATTO) tra un Fly-By and uno Swing-By...E senza dimenticare "Oumuamua"!
As the first known object of its type, Oumuamua presented a unique case for the International Astronomical Union (IAU, for short), which assigns designations for astronomical objects. Originally classified as comet C/2017 U1, it was later reclassified as Asteroid A/2017 U1, due to the absence of a coma (--> "Chioma", in Italian).
Once it was unambiguously identified as coming from outside the Solar System, a new designation was created.
The name comes from the Hawaiian word "oumuamua", meaning 'scout' (from ou, meaning 'reach out for', and mua, reduplicated for emphasis, meaning 'first, in advance of', and reflects the way this object is like a scout or messenger sent from the distant past to reach out to Humanity.
It roughly translates to 'first distant messenger' (or "The First Messenger from the distance").
Before the official name was decided upon, the name "Rama" was suggested by the name given to an Alien Spacecraft discovered under similar circumstances in the 1973 science fiction novel "Rendezvous with Rama", by Sir Arthur C. Clarke.MareKromium
(5 voti)
|
|
Comets-Comet_ISON-Nucleus_Crop_Chumack.jpgComet ISON92 visite"Comet ISON is probably at least twice as big as Comet Lovejoy and will pass a bit farther from the sun’s surface" notes Knight. “This would seem to favor Comet ISON surviving and ultimately putting on a good show.
One of the most exciting possibilities would be a partial break-up. "If Comet ISON splits, it might appear as a 'string of pearls' when viewed through a telescope," speculates Battams. “It might even resemble the famous Comet Shoemaker-Levy 9 that hit Jupiter in 1994.”
A break-up would pose no threat to Earth, assures Yeomans. "Comet ISON is not on a collision course. If it breaks up, the fragments would continue along the same safe trajectory as the original comet."
Whatever happens, northern sky watchers will get a good view. For months after it swings by the sun, Comet ISON will be well placed for observers in the northern hemisphere. It will pass almost directly over the North Pole, making it a circumpolar object visible all night long.
Will Comet ISON fizzle ... or sizzle? Stay tuned to Science@NASA for updates.MareKromium
(5 voti)
|
|
Comets-Comet_Hartley_2-EB-LXTT1.jpgComet "Hartley 2" (credits for the additional process. and color.: Elisabetta Bonora - Lunexit Team)77 visitenessun commentoMareKromium
(5 voti)
|
|
| 282 immagini su 24 pagina(e) |
 |
|
|
|
|
11 | |
|
|
|
|
