| Piú viste - The Sun: just a star, like many others... |
The Sun.jpgThe Sun62 visiteCaption NASA originale:"The ultraviolet light emitted by eleven times ionized iron at temperatures over 2 million degrees Farenheit was used to record the above picture of the Sun on September 22, 2001, the date of that year's autumnal equinox. The image was made by the EIT camera onboard the SOHO spacecraft, a space observatory which can continuously observe the Sun. Eleven times ionized iron is atomic iron with eleven of its electrons stripped away. Here the electrons are stripped by the frantic collisions with other atoms and electrons which occur at the extreme temperatures in the Solar Corona. Since electrons are negatively charged, the resulting ionized iron atom is highly positively charged. Astronomer's "shorthand" for eleven times ionized iron is written "Fe XII", the chemical symbol for iron followed by a Roman numeral 12 (Fe I is neutral iron)".
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SunFlame-Soho.jpgSolar Prominence61 visiteCaption NASA originale:"What happened to the Sun? Nothing very unusual: the strange-looking solar appendage on the lower left is actually just a spectacular looking version of a common solar prominence. A solar prominence is a cloud of solar gas held above the Sun's surface by the Sun's magnetic field. Pictured above in 2002 October, NASA's Sun-orbiting SOHO spacecraft imaged an impressively large prominence hovering over the surface, informally dubbed a flame. Over 40 Earths could line up along the vast length of the fireless flame of hovering hot gas. A quiescent prominence typically lasts about a month, and may erupt in a Coronal Mass Ejection (CME) expelling hot gas into the Solar System. Although somehow related to the Sun's changing magnetic field, the energy mechanism that creates and sustains a Solar prominence is still a topic of research".
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Sunspots-090602.jpgSunspots and Clouds in Solar Cycle 2461 visiteDa "NASA - Picture of the Day" del giorno 4 Giugno 2009:"On June 2nd, 2009, clouds over Stuttgart, Germany parted to reveal what has become a relatively rare sight, spots on the Sun. In fact, the roughly 11-year solar activity cycle is still in a surprisingly deep minimum and the years 2008 and 2009 have had the lowest Sunspot counts since the 1950s. Even the latest prediction is that the new cycle, Solar Cycle 24, will reach a maximum in May 2013 with a below-average sunspot count. The Solar Cycle 24 Sunspots recorded here are in active region AR 1019.
Previously, only two cycle 24 active regions with Sunspots, AR 1018 and AR 1017, were seen in May".MareKromium
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Sunjet.jpgA Jet from the Sun60 visiteCaption NASA:"What powers the Solar Wind? Our Sun is known to emit a powerful wind of particles with gusts that can even affect astronauts and satellites orbiting Earth. The cause of the Solar Wind has been debated for decades but is thought to be rooted in Alfvén Waves generated by the ever changing Magnetic Field of the Sun.
Newly released images from the Japanese Hinode satellite appear to bolster this hypothesis, imaging an average of 240 daily plasma jets that are excellent candidates to fuel the outwardly moving Alfvén Waves.
The jets and waves are themselves ultimately created by magnetic reconnection events, rapid events where lines of constant magnetic field suddenly move extremely rapidly, dragging electrons and protons along with them.
On the image left, one such jet is visible in X-ray light. Bright spots show relatively energetic regions elsewhere on the Sun".MareKromium
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Solar_Corona_vangorp_big.jpgSolar Corona60 visiteDa "NASA - Picture of the Day" del giorno 26 Luglio 2009:"Most photographs don't adequately portray the magnificence of the Sun's Corona. Seeing the Corona first-hand during a Total Solar Eclipse is best. The human eye can adapt to see features and extent that photographic film usually cannot.
Welcome, however, to the digital age. The above picture is a combination of 33 photographs that were digitally processed to highlight faint features of a Total Eclipse that occurred in March of 2006. The images of the Sun's Corona were digitally altered to enhance dim, outlying waves and filaments. Shadow seekers need not fret, though, since as yet there is no way that digital image processing can mimic the fun involved in experiencing a Total Solar Eclipse.
Last week, a spectacular Total Solar Eclipse occurred over Southern Asia, while the the next Total Solar Eclipse will be visible from the South Pacific on July, 11, 2010".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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Solar Flares.jpgSolar Flares58 visiteCaption NASA originale:"On June, 14th, 1999, SOHO observatory recorded this stunning view of an immense prominence erupting from the Sun's southern latitudes. The false-color image was made in the extreme Ultraviolet light produced by ionized Helium atoms in the solar plasma".
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Sun filaments.jpgSun filaments58 visiteCaption NASA originale, da NASA Picture of the Day del 6 Dicembre 2004:"Two unusually long filaments crossed part of the Sun last week. The filaments are actually relatively cool and dark prominences of solar plasma held up by the Sun's magnetic field but seen against the face of the Sun. Filaments typically last a few weeks before falling back. Pictured above, the two filaments are visible on the Sun's right side. It would take twenty Earths, set end-to-end, to match the length of one of the filaments. Also visible are bright hot regions called plages and a carpet of hundreds of granules that provide the Sun's texture. The above image was taken early last week through a small telescope in a very specific color of light emitted primarily by hydrogen".
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The_Sun-PIA09320.jpgFull Disk Image of the Sun (March 26, 2007)58 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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Solar_Eclipse-Tse2008_200_mo1_big.jpgAugust 2008 Total Solar Eclipse58 visiteCaption NASA:"For a moment on August 1st, the daytime sky grew dark along the path of a Total Solar Eclipse. While watching the geocentric celestial event from Mongolia, photographer Miloslav Druckmuller recorded multiple images with two separate cameras as the Moon blocked the bright solar disk and darkened the sky.
This final composition consists of 55 frames ranging in exposure time from 1/125 to 8 seconds. It spans nearly 12°, with the relative position of the Moon and Sun corresponding to mid-eclipse. On the left is bright planet Mercury, but many stars are also visible, including the Praesepe Star Cluster (also known as M44 or the Beehive Cluster) in Cancer, above and to the right of the silhouetted Moon. Remarkably, the nearly perfect conditions and wide range in individual exposures allow the composite picture to register the lunar surface and follow the delicate solar corona out to a distance of nearly 20 times the radius of the Sun. In fact, the composite presents a range in brightness beyond what the eye could see during the eclipse".MareKromium
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BlueSun.jpgBlue Sun58 visiteDa "NASA - Picture of the Day" del giorno 4 Novembre 2009:"Our Sun may look like all soft and fluffy, but it is not. Our Sun is an extremely large ball of bubbling hot gas, mostly Hydrogen gas. The above picture of our Sun was taken last month in a specific red color of light emitted by Hydrogen gas called "Hydrogen-alpha" and then color inverted to appear blue.
In this light, details of the Sun's Chromosphere are particularly visible, highlighting numerous thin tubes of magnetically-confined hot gas known as spicules rising from the Sun like bristles from a shag carpet.
Our Sun glows because it is hot, but it is not on fire. Fire is the rapid acquisition of Oxygen, and there is very little Oxygen on the Sun. The energy source of our Sun is the nuclear fusion of Hydrogen into Helium deep within its core. No Sunspots or large active regions were visible on the Sun this day, although some Solar Prominences are visible around the edges".MareKromium
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