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Science and Technology: Solar physics and paleontology: Set in stone
科技：太陽物理和古生物學(xué)：“石”事求是
An ancient forest reveals the sun’s behaviour 290m years ago.
遠(yuǎn)古樹木向人們揭示二億九千萬年前的太陽活動情況。
Every 11 years or so, a new sunspot cycle begins.
每隔11年左右，太陽黑子就會迎來一個新的活動周期。
Sunspots are apparent blemishes in the sun’s photosphere, the layer which emits its light.
太陽黑子是太陽光球?qū)樱刺栂蛲獍l(fā)射能量的主要大氣層）上的明顯黑斑。
Though still hot (about 3,500°C) , they are cooler than their surroundings (about 5,500°C) and thus appear dark by contrast.
雖然其溫度很高，可達(dá)到3500°C左右，但與大約5500°C的周圍環(huán)境相比溫度要低得多，所以顯得更暗。
A cycle starts with spots appearing at mid-latitudes in both northern and southern hemispheres.
在活動周期開始時，黑子出現(xiàn)在太陽南北半球的中緯度上。
Over time, the spot-generating areas migrate towards the equator.
隨著時間推移，產(chǎn)生黑子的區(qū)域不斷向赤道移動。
As they do so, the amount of light and other radiation the sun emits first increases to a maximum and then decreases to a minimum,
隨著時間推移，太陽發(fā)出的光能與其它輻射能逐漸達(dá)到峰值，隨后不斷減弱，直至黑子消失，
until the spots vanish and the cycle renews.
宣告一個完整的黑子活動周期結(jié)束。
On Earth, the increased illumination of solar maxima drives photosynthesis, and thus plant growth.
在地球上，日光亮度的不斷攀升在最大程度上促進(jìn)了光合作用，從而加快植物生長。
That permits botaniststo use trees’ annual growth rings to work out what sunspot activity was like hundreds, and occasionally thousands, of years ago.
這一現(xiàn)象使得植物學(xué)家可以通過樹木每年都會生長的年輪來判斷數(shù)百甚至數(shù)千年前的太陽黑子活動情況。
Determining solar activity millions of years ago, though, has not been so easy.
但是想要推斷幾百萬年前的黑子活動就不這么容易了。
But it is of interest to solar physicists, who wonder how far back into the past the oscillations of the sun’s magnetic field that drive the cycle go,
既便如此，太陽物理學(xué)家依然對此興趣盎然，他們想要知道這種由于太陽磁場振蕩而導(dǎo)致的周期性現(xiàn)象到底始于何時，
and how they might have changed over the course of time.
以及其循環(huán)周期在漫長的歲月中是否發(fā)生了變化。
Now, Ludwig Luthardt and Ronny Rossler of the Natural History Museum of Chemnitz, in Germany, have cracked the problem.
目前，德國的開姆尼茨自然歷史博物館的兩位研究人員，Ludwig Luthardt和Ronny Rossler已經(jīng)解決了這個問題。
英文文本來自經(jīng)濟(jì)學(xué)人 譯文來自欄目二第五組
