| Risultati della ricerca nelle immagini - "STEREO" |
EnckeCometTailRipoff_movie_short.gifComet Encke encounters a CME58 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
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McNaught-13.jpgMc Naught and its "Iron Tail"55 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
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