【万物简史】PART III CH 11马斯特·马克的夸克（15）_英语听力练习mp3下载-科学-沪江听力酷

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【万物简史】PART III CH 11马斯特·马克的夸克（15）

听力简介：

哈勃常数的含义隐藏于天文学的一个测量单位——秒差距~~~

❤《万物简史》推出部落节目版，戳这里订阅:http://bulo.yeshj.com/menu/6004/

文中需听写单词或词组用[-No-]表示，句子用[---No---]表示。请边听写边理解文意，这样可以提高听力准确度，并为训练听译打下基础哦~~~

You are of course entitled to wonder what is meant exactly by "a constant of 50" or "a constant of 100." [---1---] Except [-2-], astronomers don't use light-years. They use a distance called the parsec (a contraction of parallax and second), based on a universal measure called the stellar parallax and equivalent to 3.26 light-years. Really big measures, like the size of a universe, are measured in megaparsecs: a million parsecs. [---3---] Thus when astronomers refer to a Hubble constant of 50, what they really mean is "50 kilometers per second per megaparsec." [---4---]