Deferring to historical custom, astronomers, measure the apparent brightness of stars through the magnitude scale, a very confusing way . 按照历史习惯，天文学家用星等标这种容易使人混淆的方法来度量恒星的视亮度。
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Analysis showed this might be due to the fact that a black hole passed in front of the star . the gravitation of a black hole can function as a convex lens and focus starlight , resulting in transience increase of apparent brightness of the star 分析显示，这很可能是因为有一个黑洞在恒星前面经过，黑洞的引力会聚了星光，就像凸透镜把光线聚焦一样，使恒星的视亮度增加。
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We found that the luminosities of type i supernovae are about the same . therefore , we can compute the distance to a galaxy by measuring the apparent brightness of a type i supernova in that galaxy , if we can find one 科学家发现原来所有这种超新星爆发的光度都是差不多的，所以我们只要找到这种超新星，便可以由它的视亮度推算出它和地球的距离，从而得知它所处身星系的距离。
