The cause of the opening and closing is probably the difference in light.

开启和关闭的原因可能是光线的不同。

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Although we talked about Vitamin D and sunlight, it can make a huge difference in how you feel if you go to a tanning salon to get some light on your skin.

尽管我们已谈到维生素D和阳光，但是如果你刻意去参加日晒沙龙来摄取阳光到皮肤的话，它会让你感觉到巨大的差别。

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Then she was able to capture the sharp difference between light and dark.

VOA: special.2009.05.10

And then he just takes that narrow column of light and he admits it to a prism. And what the prism does is takes a tiny, tiny difference in wavelength and refracts it through a different angle.

他只取了那个窄光柱,然后把它对准一个棱镜，棱镜所做的就是,测量出波长的细微差别,然后从不同的角度测定它的折射度。

麻省理工公开课 - 固态化学导论课程节选

And what we predict as an energy difference between two levels, we know should correspond to the energy of light that's either emitted, if we're giving off a photon, or that's absorbed if we're going to take on a photon and jump from a lower to a higher energy level.

我们预测，两个能级之间的能量差，我们知道，它要么和发出的光有关,如果它发出光子的话，要么它吸收光子,从低能级跃迁到，更高能级上去。

麻省理工公开课 - 化学原理课程节选

All of these questions can be explored in the interactive calculator CNN created to help shed light on the difference in legal protections among the 50 states.

CNN: America is at a crossroads on gay rights

The only difference is the light.

WSJ: Lighting Designer Al Gurdon: The Light Master of Super Bowl Halftime

Because radiation from the Crab nebula is so energetic, the electrons that created it must have been travelling very close to the speed of light so close that the difference between the two speeds would bump up against Planck-scale graininess, and show up in the spectrum of the radiation.

ECONOMIST: Planck-scale physics