~ 黝黑的炎熱太陽 ~
Dark Sun Sizzling <br />
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<img src="http://i1.tinypic.com/2ljqfk7.jpg" border="0" onclick="zoom(this)" onload="attachimg(this, 'load')" alt="" /><br />
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影像提供: TRACE Project, Stanford-Lockheed Institute for Space Research, NASA <br />
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<font color="navy">Explanation:</font><br />
Is this our Sun? Yes. Even on a normal day, our Sun is sizzling ball of seething hot gas. Unpredictably, regions of strong and tangled magnetic fields arise, causing sunspots and bright active regions. The Sun's surface bubbles as hot hydrogen gas streams along looping magnetic fields. These active regions channel gas along magnetic loops, usually falling back but sometimes escaping into the solar corona or out into space as the solar wind. Pictured above is our Sun in three colors of ultraviolet light. Since only active regions emit significant amounts of energetic ultraviolet light, most of the Sun appears dark. The colorful portions glow spectacularly, pinpointing the Sun's hottest and most violent regions. Although the Sun is constantly changing, the rate of visible light it emits has been relatively stable over the past five billion years, allowing life to emerge on Earth. <br />
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<font color="navy">說明: </font><br />
這是我們的太陽嗎？是的！就是在平時的日子裡，太陽還是一團翻騰不休的炎熱 氣體 球；無法預測地出現由糾結強磁場所構成的區域，造成太陽黑子與明亮的活躍區。太陽表面的泡泡狀結構，是來自沿環狀磁場線流竄的熾熱氫氣噴流。在這些活耀區內，沿磁線衝出的氣體通常會再掉回太陽表面，不過有時候也會衝入日冕層，甚至逃逸到太空中成為太陽風。上面影像中的太陽，是由在三個紫外光波段拍攝的照片合成出來的。因為只有活躍區才會發出大量的高能量紫外光，所以大部份的太陽看起來很暗。亮麗、明亮多彩的區域，通常是太陽最熱也是活動最猛烈的區域。雖然太陽不斷的發生變化，但是它可見光波段的輸出在過去的五十億年之間相對穩定，讓生命能夠在地球上立足。<br />
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<font size="2">資料來源: Scientific American<br />
Department of Physics, NCKU</font>