One way to do that is with a spectrograph, which breaks light into a rainbow of colors; artificial light makes for a different sort of rainbow from the one sunlight produces.

一个判断方法是用光谱仪，它可以将光分成各种颜色，而人造光的颜色排列与阳光是不同的。

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By training a spectrograph on this light, scientists can tease out the composition of the planet's atmosphere.

通过将光谱仪对准这些光线，科学家们将可以梳理出这颗行星的大气层成分。

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Molecules around stars leave imprints in their light, which the spectrograph can detect.

恒星中的分子会在光谱中留下特殊标识，通过摄谱仪就能识别。

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In addition, there is a spectrograph that will slice light into its component colours so scientists can discern something of the chemistry of far-flung phenomena.

BBC: Science & Environment