| Piú votate - The Sun: just a star, like many others... |
The_Sun-PIA09330.jpgThe South Pole of the Sun66 visiteSTEREO, a two-year mission, launched October 2006, will provide a unique and revolutionary view of the Sun-Earth System. The two nearly identical observatories -- one ahead of Earth in its orbit, the other trailing behind -- will trace the flow of energy and matter from the Sun to Earth. They will reveal the 3D structure of coronal mass ejections; violent eruptions of matter from the sun that can disrupt satellites and power grids, and help us understand why they happen. STEREO will become a key addition to the fleet of space weather detection satellites by providing more accurate alerts for the arrival time of Earth-directed solar ejections with its unique side-viewing perspective. MareKromium
(6 voti)
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Green-Sun.jpgGreen flash from Italy54 visiteCaption originale, da "NASA - Picture of the Day" del 29 Gennaio 2007:"How could the Sun turn green? Difficult to observe, the momentary green flash above the rising or setting Sun has been documented as a phenomenon caused by the atmospheric bending or refraction of sunlight.
Like a weak prism, the Earth's atmosphere breaks white sunlight into colors, bending red colors slightly and green and blue colors through increasingly larger angles.
When the sky is (VERY) clear, a green flash just above the Sun's edge can sometimes be seen for a second or so, when the sun is close to a distant horizon. Still, from a site atop Mt. Autore (altitude 1.850 mt) in Italy, astrophotographer Danilo Pivato captured this dramatic green flash movie. The time between frames varies from over one minute in the beginning to about one second as the flash becomes visible".
(6 voti)
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Earth&Sun-001-magfieldG_b.jpgMagnetic Fields... (2)54 visitenessun commento
(6 voti)
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Solar Prominence.jpgSolar "Blow"...66 visiteDa "NASA - Picture of the Day" del 7 Agosto 2006:"Our Sun is still very active. In the year 2000, our Sun went though Solar Maximum, the time in its 11-year cycle where the most sunspots and explosive activities occur. Sunspots, the Solar Cycle, and Solar Prominences are all caused by the Sun's changing magnetic field.
Pictured above is a solar prominence that erupted in 2002, July, throwing electrons and ions out into the Solar System.
The above image was taken in the ultraviolet light emitted by a specific type of Ionized Helium, a common element on the Sun. Particularly hot areas appear in white, while relatively cool areas appear in red. Our Sun should gradually quiet down until Solar Minimum occurs, and the Sun is most quiet. No one can precisely predict when Solar Minimum will occur, although some signs indicate that it has started already".
(6 voti)
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Sunspot.jpgSunspots' Region 87572 visiteCaption NASA originale (da "NASA - Picture of the Day" del 2 Maggio 2006):"An unusually active Sunspot Region is now crossing the Sun.
The Region, numbered 875, is larger than the Earth and has produced several Solar Flares over the past week. It should take a few more days for Sunspot 875 to finish crossing the solar disk. The above image of the Sun was taken last Wednesday in a very specific color of red light to bring up detail. Sunspot 875, in the midst of erupting a large "Class C" Solar Flare, can be seen as the dark region to the upper right. In the above image, relatively cool regions appear dark while hot regions appear bright.
On the far left, solar prominences are visible hovering above the Sun's surface".
(6 voti)
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Solar Flare.jpgLoops over the Sun57 visiteCaption originale:"How can gas float above the Sun? Twisted magnetic fields arching from the Solar Surface can trap ionized gas, suspending it in huge looping structures. These majestic plasma arches are seen as prominences above the Solar Limb. In September 1999, this dramatic and detailed image was recorded by the EIT experiment on board the space-based SOHO observatory in the light emitted by ionized Helium. It shows hot plasma escaping into space as a fiery prominence breaks free from magnetic confinement a hundred thousand kilometers above the Sun. These awesome events bear watching as they can affect communications and power systems over 100 MKM away on Planet Earth".
(6 voti)
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Sun-Saturn-IMG001612-br500.jpgSaturn's "superior conjunction"57 visiteIn this SOHO image taken July 21, 2005, the Sun is represented by the white circle in the center. Saturn is the bright object to the left of the Sun. Interestingly, the streak accompanying Saturn is not the rings but a distortion caused by Saturn's brightness. Saturn is approaching "superior conjunction," that is, it will be almost directly behind the Sun from Earth - thus the Cassini spacecraft, in orbit around Saturn, will not be able to send or receive transmissions normally. Regular science data collection has been temporarily suspended.
As Cassini passes closest by the limb of the Sun on July 24 PDT, all the communications will be impossible because of the Sun's radio noise. The spacecraft will regain full communication with Earth on July 27, once again returning Saturn science data. In the meantime, controllers are sending approximately 100 commands per day to test communication status. Cassini radio scientists are taking advantage of this opportunity to study the Sun's corona from its effects on the radio signals that reach Earth.
SOHO (Solar and Heliospheric Observatory Satellite) orbits the Sun parked in one of the five gravitational-neutral spots, called Lagrange Points. This specific spot, called L1, stays in the same place relative to the Sun and the Earth, offering a continuously uninterrupted view of the Sun.
(6 voti)
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Hungarian Eclypse.jpgMoments of the last Total Eclipse55 visiteCaption NASA originale:"Only in the fleeting darkness of a total solar eclipse is the light of the Solar Corona easily visible from Earth. Normally overwhelmed by the bright solar disk, the expansive corona, the Sun's outer atmosphere, is an alluring sight. But the subtle details and extreme ranges in the corona's brightness discernible to the eye are notoriously difficult to photograph. In this series of images recorded from Siofok, Hungary during the total phase of the August 11, 1999 eclipse, progressively longer exposures (top left to bottom center) have been used to more faithfully capture different regions of the elusive solar corona. The final image (at bottom right) shows light from the solar disk emerging from behind the moon's edge at the end of totality".
(6 voti)
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A_-_The_Sun_-_Sunspots_-_Friedman.jpgFeatures of the Sun (picture taken in H-Alpha - False Colors)132 visiteTaken just last week (second week of November 2011), the Sun was captured sporting numerous interesting features including one of the larger Sunspot Groups yet recorded: AR 1339 visible on the image right. Only last year, the Sun was emerging from an unusually quiet Solar Minimum that lasted for years. The above image was recorded in a single color of light called Hydrogen Alpha, inverted, and false colored. Spicules cover much of the Sun's face. The gradual brightening towards the Sun's edges is caused by increased absorption of relatively cool solar gas and called limb darkening. Just over the Sun's edges, several scintillating Prominences protrude, while Prominences on the Sun's face are seen as light streaks. Possibly the most visually interesting of all are the magnetically tangled active regions containing cool Sunspots. As our Sun's Magnetic Field winds toward Solar Maximum over the next few years, increased activity will likely create times when the Sun's face is even more complex.MareKromium
(5 voti)
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A-The_Sun-SOHO-LASCO-1.gifA Day of the Sun (a GIF-Movie by Dr Gianluigi Barca - Lunexit Team)88 visitenessun commentoMareKromium
(5 voti)
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A-The_Sun-SOHO-LASCO-2.gifA Day of the Sun (a GIF-Movie by Dr Gianluigi Barca - Lunexit Team)90 visitenessun commentoMareKromium
(5 voti)
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Solar_Prominence-SOHO.jpgSolar Prominence103 visiteCaption NASA:"What's that coming over the edge of the Sun? What might appear at first glance to be some sort of Sun monster is actually a Solar Prominence. The above Prominence, captured by the Sun-orbiting SOHO satellite earlier this year during an early stage of its eruption, rapidly became one of the largest ever on record.
Even as pictured, the Prominence is huge -- the Earth would easily fit inside. A Solar Prominence is a thin cloud of Solar Gas held just above the Surface by the Sun's Magnetic Field.
A "Quiescent Prominence" typically lasts about a month, while an "Eruptive Prominence" like the one developing above may erupt within hours into a Coronal Mass Ejection (CME), expelling hot gas into the Solar System. Although very hot, Prominences typically appear dark when viewed against the Sun, since they are slightly cooler than the surface. As our Sun evolves toward Solar maximum over the next three years, more large eruptive prominences are expected".MareKromium
(5 voti)
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