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Active Regions, CMEs, and X-
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| Title |
Active Regions, CMEs, and X-Class Flares |
| Explanation |
Space Weather forcasters [ http://sec.noaa.gov/today.html ] are predicting major storm conditions over the next few days as the active Sun [ http://www.dxlc.com/solar/ ] has produced [ http://pao.gsfc.nasa.gov/gsfc/spacesci/solarexp/soho.htm ] at least three strong flares and a large coronal mass ejection (CME) since Tuesday, June 6th [ http://sohowww.nascom.nasa.gov/hotshots/ ]. This recent [ http://umbra.nascom.nasa.gov/images/latest.html ] false color X-ray image [ http://www.lmsal.com/SXT/Oimages.html ] of the Sun shows the active region generating the explosive events, here the Sun's [ http://antwrp.gsfc.nasa.gov/apod/ap981221.html ] most intense source of X-rays [ http://imagine.gsfc.nasa.gov/docs/science/know_l2/ history_xray.html ], as the dominant bright area just above center. X-ray hot plasma suspended in looping magnetic fields arcs above this region, cataloged as AR9026. AR9026 appears as a large group of sunspots [ http://es.rice.edu/ES/humsoc/Galileo/Things/ sunspots.html ] in visible light images. The three intense flares were all X-class events, the most severe class of solar flares based on X-ray flux measurements [ http://sec.noaa.gov/rt_plots/xray_5m.cgi ] by the earth-orbiting GOES [ http://www.earth.nasa.gov/history/goes/goes.html ] satellites. Energetic particles from the CME [ http://antwrp.gsfc.nasa.gov/apod/ap000309.html ], associated with the second X-class flare, were directed toward [ http://www.spaceweather.com/images/new/cme.html ] planet Earth and could produce geomagnetic storms [ http://sec.noaa.gov/NOAAscales/index.html ] as early as today. Possible effects range from increased auroral displays [ http://sec.noaa.gov/pmap/index.html ] to disruptions of satellite and communications systems and electrical power grids. But wait ... there's more! In the coming days AR9026, carried slowly across the Sun (from left to right) by solar rotation [ http://antwrp.gsfc.nasa.gov/apod/ap991021.html ], is likely to produce even more solar flares [ http://hesperia.gsfc.nasa.gov/sftheory/ ]. |
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Sunspot Stack
| Title |
Sunspot Stack |
| Explanation |
Welcome to multiwavelength astronomy [ http://imagine.gsfc.nasa.gov/docs/science/know_l2/ multiwavelength.html ]! From top to bottom, these stacked panels show the largest sunspot group in a decade in visible, extreme ultraviolet, and x-ray light. All were taken on March 29, around the time [ http://sohowww.nascom.nasa.gov/hotshots/2001_03_29/ ] the famous solar active region, cataloged as AR 9393 [ http://antwrp.gsfc.nasa.gov/apod/ap010411.html ], was at its peak size -- over 10 times the size of planet Earth. The panels illustrate how the "appearance" of the active region changes, when imaged in electromagnetic radiation [ http://www.colorado.edu/physics/2000/ waves_particles/ ] (light) of progressively shorter wavelengths. In the visible light panel, dark islands [ http://antwrp.gsfc.nasa.gov/apod/ap010315.html ] of sunspots stand out against the bright solar surface, but the situation seems to be reversed in the extreme ultraviolet panel with a bright active region seen against a darker background. Finally, the x-ray panel reveals majestic loops of glowing plasma arcing far above the sunspot group. Why do pictures [ http://www.lmsal.com/YPOP/SOLARWEEK/ ] of the same part of the Sun [ http://observe.ivv.nasa.gov/nasa/exhibits/sun/sun_1.html ] look so different? Made at different wavelengths, each panel actually records a different layer [ http://www.lmsal.com/YPOP/Spotlight/SunInfo/ Structure.html ] in the solar atmosphere. Top to bottom, the altitude of each layer (along with temperature) increases, starting with the Sun's visible surface or photosphere [ http://solar-center.stanford.edu/hidden-pic/ photosphere.html ] (about 5 thousand kelvins), then the chromosphere [ http://science.nasa.gov/ssl/pad/solar/ chromos.htm ] / transition region [ http://science.nasa.gov/ssl/pad/solar/t_region.htm ] (ten to a hundred thousand kelvins [ http://lamar.colostate.edu/~hillger/temps.htm ]), and finally the solar corona [ http://www.lmsal.com/YPOP/Spotlight/Tour/ corona2.html ] (millions of kelvins). |
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Solar Magnetic Bananas
| Title |
Solar Magnetic Bananas |
| Explanation |
Is that our Sun [ http://www.seds.org/nineplanets/nineplanets/sol.html ]? The unusual banana [ http://www.dole5aday.com/bobby/shocked_audio/radio_swa_letsgo.html ]-shaped loops shown above [ http://science.msfc.nasa.gov/newhome/headlines/ast22jun98_1.htm ] are actually part of a computer-generated snap-shot of our Sun's magnetic field [ http://vestige.lmsal.com/TRACE/Public/magnetic.htm ]. This animated frame [ http://science.msfc.nasa.gov/ssl/pad/solar/3dfields.htm ] was constructed using data from the ground-based U.S. Solar Vector Magnetograph [ http://wwwssl.msfc.nasa.gov/ssl/pad/solar/maggraph.htm ] and the space-based Japanese X-Ray Telescope Yohkoh [ http://solar.physics.montana.edu/YPOP/ ]. Surfaces of constant magnetic field [ http://www-spof.gsfc.nasa.gov/Education/Imagnet.html ] strength loop through the Sun's corona [ http://antwrp.gsfc.nasa.gov/apod/ap951024.html ], break through the Sun's surface, and connect regions of magnetic activity such as sunspots [ http://antwrp.gsfc.nasa.gov/apod/ap980322.html ]. Recently, contact has been interrupted [ http://sohowww.nascom.nasa.gov/pr26june.html ] with the Sun-watching SOHO [ http://sohowww.nascom.nasa.gov/ ] satellite. Although SOHO had completed its two year mission, attempts are still being made to re-establish communication. |
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