In astronomy, in optical astronomy, we cannot measure the period or the frequency of optical light.

在天文学中，在光学天文学中，我们不能测量周期或者可见光的频率。

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This means in optical light telescopes, like the VLT, there is little to see.

这意味着光学望远镜，如VLT，将很难看到它。

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The Heart Nebula, officially dubbed IC 1805 and visible in the above right, has a shape in optical light reminiscent of a classical heart symbol.

心脏星云，正式名称为IC 1805，在上图右边可见，在可见光波段有着让人联想到经典的心脏符号的形状。

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Mister Kao discovered how to transmit,or send,light signals over long distances through optical glass fibers.

VOA: special.2009.12.08

It is called LaserFest. The American Physical Society, the Optical Society ,and SPIE, a group that supports the study of light, all have been involved.

VOA: special.2010.09.01

The universe is pretty transparent to optical light--that's how we can see far away galaxies.

FORBES: How To Talk To Aliens

Gamma-rays are the most energetic form of light, with wavelengths far shorter than ordinary optical light (the light your eye can see), or even ultraviolet or X-ray light.

CNN: Why gamma-ray burst shocked scientists

The galactic centre can only be observed at certain wavelengths - such as X-rays - because large amounts of dust lie in our line of sight, blocking out optical light.

BBC: Arches Cluster, Leicester