One source of error is refraction, the bending of light beams as they pass through air layers of different temperature and pressure.

误差的一个来源是折射，即光束通过不同温度和压力的空气层时发生的弯曲现象。

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If a large object passes in front of a more distant background star, it may act as a lens, bending and distorting the light of that star so that it may appear to brighten significantly.

如果一个体积足够大的星体从一个距离很远的恒星前面经过，那么会产生透镜效果，使那个恒星的光线产生弯曲或变形，这样就能很清楚的看到这个星体。

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In this method, when one star passes in front of another, as seen from Earth, the nearer star's gravity ACTS like a lens, bending and magnifying the more distant star's light.

当天文学家用这种方法从地球上观测到一颗恒星在另一颗恒星前“走过”时，距地球较近的这颗恒星的重力就如同一个镜头，将较远的那颗恒星的光弯曲并放大。

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And so will the fortunes of those who get in early and build the right light-bending products.

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But researchers quickly found out that the mathematics behind bending these light waves, called transformation optics, could also be applied to sound waves.

BBC: Acoustic 'cloaking device' shields objects from sound

The bending creates a lensing effect in the same way that light is bent through glass or plastic in a microscope or your eyeglasses.

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