Although scientists believe an octopus is most likely color blind, Paul may still be able to see horizontal lines, as well as levels of brightness and object size.

尽管科学家认为章鱼多半色盲，但保罗也许仍保留了一些对水平线条、明亮度、物体大小的感应。

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The distance to such an object can be worked out by comparing its apparent brightness with its known, absolute brightness.

经过比较表观亮度和已知的绝对亮度，即可得出该天体和我们的距离。

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"This object was changing its brightness by a factor of three or four -- it was just enormously variable, " Tholen said.

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Kepler flags exoplanet candidates via the transit method, which looks for dips in a star's brightness caused by an object crossing in front of it.

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Textures are well-defined-like water rippling in a trough-and the changes in definition and brightness as you move in relationship to an object are impressive.

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