charles 2009-3-23 11:38
太陽光譜
The Solar Spectrum
[img]http://i10.tinypic.com/4dfgu8l.jpg[/img]
影像版權與提供: Nigel Sharp (NSF), FTS, NSO, KPNO, AURA, NSF
[color=navy]Explanation: [/color]
[color=dimgray]It is still not known why the Sun's light is missing some colors. Shown above are all the visible colors of the Sun, produced by passing the Sun's light through a prism-like device. The above spectrum was created at the McMath-Pierce Solar Observatory and shows, first off, that although our yellow-appearing Sun emits light of nearly every color, it does indeed appear brightest in yellow-green light. The dark patches in the above spectrum arise from gas at or above the Sun's surface absorbing sunlight emitted below. Since different types of gas absorb different colors of light, it is possible to determine what gasses compose the Sun. Helium, for example, was first discovered in 1870 on a solar spectrum and only later found here on Earth. Today, the majority of spectral absorption lines have been identified - but not all. [/color]
[color=navy]說明:[/color]
[color=dimgray]到現在為止，我們還是不知道為什麼有些顏色的陽光不見了！ 上圖是我們的太陽在可見光波段的光譜，它是陽光通過一部基本原理和三稜鏡很相似的儀器後所產生的。 在這張光譜裡，可以看到七彩的太陽光譜有許多黑色的暗線，而到目前為止，天文學家還是不了解有些暗線是怎麼形成的。 上面這幅光譜是由名為麥克梅斯-皮爾斯 (McMath-Pierce)的太陽塔所產生的，由光譜可以看出外觀是黃色的太陽雖然會發出各種顏色的輻射，但是還是以黃-綠光附近的輻射最強。 這幅光譜會有暗線，是因為太陽表面和它上方的氣體吸收部份來自下方的陽光。 因為不同種類的氣體會吸收不同顏色的光，所以從這些吸收暗線，我們可以定出太陽表面的氣體組成。 舉例來說，氦就是在1870年首先在太陽光譜中發現的新元素，後來才在地球上找到它的蹤跡。 到目前為止，大部份吸收譜線的來源多已經知道，不過，還是有數條線的出處仍然不明。 [/color]
[size=2]資料來源: Scientific American
Department of Physics, NCKU[/size][color=white][size=1]
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