| Piú votate - The Sun: just a star, like many others... |
Sungrazer-2010-SOHO.jpgSungrazer54 visiteCaption NASA:"Intense and overwhelming, the direct glare of the Sun is blocked by the smooth occulting disk in this image from the Sun-staring SOHO Spacecraft. Taken on January 3rd, 2010, an extreme UltraViolet image of the Sun to scale, is superimposed at the center of the disk. Beyond the disk's outer boundary, is a Sungrazer Comet, one of the brightest yet seen by SOHO.
The comet was discovered by an Australian Amateur Astronomer, Alan Watson, while examining earlier images from another Sun-watching Spacecraft, STEREO-A. Based on their orbits, Sungrazers are believed to belong to the Kreutz family of comets, created by successive break ups from a single large Parent Comet that passed very near the Sun in the twelfth century.
Subjected to strong Tidal Forces and intense Solar Heat, this Sungrazer did not survive its close encounter".MareKromium
(3 voti)
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Solar_Prominence-STEREO.jpgHuge Solar Prominence55 visiteCaption NASA:"What does a Solar Prominence look like in three dimensions? To help find out, NASA launched the STEREO satellites to keep a steady eye on the Sun from two different vantage points.
The STEREO satellites orbit the Sun nearly along Earth's orbit, but one (dubbed "Ahead" ---> Avanti) currently leads the Earth, while the other (dubbed "Behind" ---> "Dietro") currently trails. Three weeks ago, a powerful Prominence erupted and remained above the Sun for about 30 hours, allowing the STEREO satellites to get numerous views of it from different angles.
Pictured above is a High-Resolution image of the event from the STEREO "Ahead" satellite.
A video of the Prominence erupting as seen from both Spacecrafts can be found at http : // www . youtube . com / watch?v = _RjswBx6ysQ.
The unusually quiet nature of the Sun over the past two years has made large prominences like this relatively rare. The combined perspective of STEREO will help astronomers better understand the mechanisms for the creation and evolution of Prominences, Coronal Mass Ejections, and Solar Flares".
MareKromium
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PerihelionAphelion_cervignon800.jpgPerihelion and Aphelion55 visiteDa "NASA - Picture of the Day" del giorno 3 Luglio 2009:"This year Aphelion, the point in Earth's elliptical orbit when it is farthest from the Sun, occurs tomorrow, July 4th.
Of course, that doesn't affect the seasons on our fair Planet, because those are determined by the tilt of Earth's Axis of Rotation and not Earth's distance from the Sun: so July is still Winter in the South and Summer in Northern Hemisphere. But it does mean that on July 4th the Sun will be at its smallest apparent size. This composite neatly compares two pictures of the Sun taken with the same telescope and camera on the dates of Perihelion (closest approach) and Aphelion in 2008.
The image labels include Earth's distance in kilometers from the Sun on the two dates.
Otherwise difficult to notice, the change in the Sun's apparent diameter between Perihelion and Aphelion is clear. The difference amounts to a little over 3%".MareKromium
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The_Sun-01.jpgThe Sun in 3D54 visitenessun commentoMareKromium
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The_Sun-00.jpgThe Sun in 3D54 visitenessun commentoMareKromium
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The_Sun-Coronal_Hole.jpgCoronal Hole58 visiteCaption NASA:"The dark expanse below the Equator of the Sun is a Coronal Hole, such as a Low Density Region extending above the surface, where the Solar Magnetic Field opens freely into interplanetary space.
Shown in false color, the picture was recorded on September 19th, 2007, in Extreme Ultraviolet Light by the EIT instrument onboard the space-based SOHO observatory. Studied extensively from space since the 1960s in ultraviolet and x-ray light, Coronal Holes are known to be the source of the high-speed Solar Wind, atoms and electrons that flow outward along the open magnetic field lines.
The Solar Wind streaming from this coronal hole triggered colorful auroral displays on planet Earth begining late last week, enjoyed by spaceweather watchers at high latitudes".MareKromium
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The_Sun-PIA09328.jpgThe North Pole of the Sun59 visiteNASA's Solar TErrestrial RElations Observatory (STEREO) satellites have provided the first three-dimensional images of the Sun. For the first time, scientists will be able to see structures in the Sun's atmosphere in 3D.
The new view will greatly aid scientists' ability to understand solar physics and thereby improve space weather forecasting.
The EUVI imager is sensitive to wavelengths of light in the extreme ultraviolet portion of the spectrum.
EUVI bands at wavelengths of 304, 171 and 195 Angstroms have been mapped to the red blue and green visible portion of the spectrum; and processed to emphasize the temperature difference of the solar material.
In this picture, a large spicule can be seen. MareKromium
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The Sun-UvcseitG_c.jpgOur "restless" Sun... (12)54 visitenessun commento
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The Sun-TricutG-1.jpgOur "restless" Sun... (11)54 visitenesun commento
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The Sun-Suncombo1G.jpgOur "restless" Sun... (10)54 visitenessun commento
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The Sun-EitplumeG.jpgOur "restless" Sun... (9)54 visitenessun commento
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The Sun-Eit171cfG.jpgOur "restless" Sun... (8)54 visitenessun commento
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