|
|
LLO-Itokawa-ST_2563511720_v.jpgThe unbelievable surface of 25143-Itokawa (HR5 - possible natural colors; elab. Lunexit)52 visitenessun commentoMareKromium
|
|
LLN-Itokawa-ST_2506464135_v.pngApproaching Itokawa (1 - natural colors; elab. Lunexit)53 visitenessun commentoMareKromium
|
|
LLN-Itokawa-ST_2506540935_v.pngApproaching Itokawa (2 - natural colors; elab. Lunexit)52 visitenessun commentoMareKromium
|
|
LLN-Itokawa-ST_2506694595_v.pngApproaching Itokawa (3 - natural colors; elab. Lunexit)52 visitenessun commentoMareKromium
|
|
LLN-Itokawa-ST_2506733028_v.pngApproaching Itokawa (4 - natural colors; elab. Lunexit)52 visitenessun commentoMareKromium
|
|
LLN-Itokawa-ST_2539429953_v.jpgThe unbelievable surface of 25143-Itokawa (HR - possible natural colors; elab. Lunexit)52 visiteIl piccolo Asteroide Itokawa si mostra ancora una volta per ci che : un piccolo mondo senza crateri e, apparentemente, senza polveri, la cui superficie - come questa splendida immagine HR ottenuta dalla Sonda JAXA "Hayabusa" - sembra risolversi in una serie di strati "a squame", tutti sensibilmente inclinati rispetto al piano dell'asteroide e, forse, piuttosto affilati (ci ricordano, in versione pi grande, i "Razorblades" dei Crateri Endurance e Victoria (Marte).
Un piccolo mondo che, dopo un breve periodo di "fama", ripiombato nell'oblo collettivo, dopo che la Sonda JAXA "Hayabusa" ha malfunzionato (in circostanze e per cause ancora abbastanza oscure).
I Giapponesi, come ovvio, hanno preso molto male questo incidente, ma la coltre di silenzio che caduta sulla Missione - la quale, come saprete, ha mostrato alla Terra il primo (ed unico?) Corpo Celeste PRIVO di crateri (un altro "schiaffo" per uno dei Maggiori Dogmi dell'Astronomia Convenzionale) - ha lasciato tutti molto perplessi.MareKromium
|
|
Comets-Comet_Holmes.jpgComet 17-P-Holmes52 visiteCaption NASA, da "NASA - Picture of the Day" del 26 Ottobre 2007:"Comet 17 P-Holmes stunned comet watchers across planet Earth earlier this week.
On October 24th, 2007, it increased in brightness over half a million times in a matter of hours. The outburst transformed it from an obscure and faint comet quietly orbiting the Sun with a period of about 7 years to a naked-eye comet rivaling the brighter stars in the constellation of Perseus. Recorded on that date, this view from Teheran, Iran, highlights the comet's (enhanced and circled) dramatic new visibility in urban skies.
The inset (left) is a telescopic image from a backyard in Buffalo, New York showing the comet's greatly expanded coma, but apparent lack of a tail. Holmes' outburst could be due to a sudden exposure of fresh cometary ice or even the breakup of the comet nucleus. The comet may well remain bright in the coming days".MareKromium
|
|
EnckeCometTailRipoff_movie_short.gifComet Encke encounters a CME52 visiteCaption NASA:"Swinging inside the orbit of Mercury, on April 20th, 2007, periodic comet Encke encountered a blast from the Sun in the form of a Coronal Mass Ejection (CME). When CMEs, enormous clouds of energetic particles ejected from the Sun, slam into Earth's magnetosphere, they often trigger auroral displays.
But in this case, the collison carried the tail of the comet away.
The tail was likely ripped off by interacting magnetic fields rather than the mechanical pressure of the collision.
This a GIF-movie showing the remarkable event as recorded by the Heliospheric Imager onboard the STEREO A spacecraft. In the movie, the time between frames is about 45 minutes, while the frames span about 14x20 MKM at the distance of the comet. Of course, similar collisions have happened before as the ancient comet loops through its 3,3 year solar orbit. So don't worry, Encke's tail will grow back!".MareKromium
|
|
MATHILDE_FLY-BY.gifMathilde (NEAR Probe Fly-By)52 visiteGuardate bene: osservate il "main crater" di Mathilde, cos (enorme-mente) simile allo Stickney Crater di Phobos e poi, se volete, provate a pensare...Crateri troppo grandi, per mondi troppo piccoli!
Che ne dite?MareKromium
|
|
Eris_Dysnomia.jpgEris and Dysnomia54 visiteNASA's HST has teamed up with the W.M. Keck Observatory to precisely measure the mass of Eris, the largest member of a new class of Dwarf Planets in our Solar System. Eris is 1,27 times the mass of Pluto, formerly the largest member of the Kuiper Belt of icy objects beyond Neptune.
Hubble observations in 2006 showed that Eris is slightly physically larger than Pluto. But the mass could only be calculated by observing the orbital motion of the moon Dysnomia around Eris. Multiple images of Dysnomia's movement along its orbit were taken by Hubble and Keck.
Astronomer Mike Brown of the California Institute of Technology in Pasadena, Calif. and colleagues also report in this week's Science Magazine that Dysnomia is in a nearly circular 16-day orbit. This favors the idea that Dysnomia was born out of a collision between Eris and another Kuiper Belt object (KBO).
A gravitationally captured object would be expected to be in a more elliptical orbit.
The satellites of Pluto, as well as the Earth-Moon system are also believed to have been born out of a collision process where debris from the smashup goes into orbit and coalesces into a satellite.
By comparing the mass and diameter, Brown has calculated a density for Eris of 2.3 grams per cubic centimeter. This is very similar to the density of Pluto, the large Kuiper Belt object 2003 EL61, and Neptune's moon Triton which is likely a captured KBO. These higher densities imply that these bodies are not pure ice but must have a significant rocky composition.
The discovery of Eris in 2005 (originally nicknamed Xena, and officially cataloged 2003 UB313) prompted a debate over the planetary status of Pluto because astronomers realized they would have to call it the "10th" planet if Pluto retained its own planetary status, which was already under debate. This led the International Astronomical Union, in 2006, to make a new class of solar system object called dwarf planets. These are spherical bodies in hydrostatic equilibrium (objects that have sufficient gravity to overcome their own rigidity and form a spherical shape) like the planets, but unlike the major planets in the solar system, they have not gravitationally cleared out the neighborhood of particles and small debris along their orbits.
MareKromium
|
|
McNaught-13.jpgMc Naught and its "Iron Tail"54 visiteCaption NASA:"Outstanding in planet Earth's sky early this year, Comet McNaught is captured in this view from the STEREO A spacecraft. McNaught's coma is so bright, it blooms into the long horizontal stripe at the bottom of the field. Brilliant Venus, near the top left corner, also produces a severe horizontal blemish in the digital image. But the sensitive camera does accurately record the striations in McNaught's famous dust tail along a region stretching over 30 MKM toward the top right of the field of view. A separate, fainter, arching tail just to the left of the dust tail was initially thought to be an example of a common ion tail, formed by electrically charged atoms carried away from the comet by the Solar Wind.
However, detailed modeling indicates that tail is actually due to Neutral Iron atoms pushed out by the pressure of sunlight - the first ever detected Neutral Iron tail from a comet. The Iron atoms are thought to originate in dust grains from the comet nucleus that contain the Iron-Sulfur mineral Troilite (FeS)". MareKromium
|
|
Man-Made_Nebula.gifMan-Made Nebula, such as: a warning sign of the Kessler Syndrome (GIF Movie)75 visiteCaption NASA:"What's that cloud drifting in space? It's not an astronomical nebula because...those appear to stay put.
Atmospheric clouds don't look like this.
The answer to last week's sky mystery turned out to be orbiting and expanding debris from the upper stage of a failed Russian rocket that exploded unexpectedly. The cloud became visible to unaided southern hemisphere observers, and its cause was initially unknown. The above time lapse movie shows the cloud drifting as seen from Australia. Streaks in and near the cloud are likely large pieces of debris. The debris cloud is more than an astronomical curiosity -- particles from this cloud and others could become projectiles damaging existing satellites. As the cloud disperses, many particles will fall to Earth, but many more may help make low Earth orbit an increasingly hostile environment".MareKromium
|
|
| 271 immagini su 23 pagina(e) |
 |
|
|
|
|
11 | |
|
|
|
|
