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When confronted with the topic of stars and galaxies, a question that tantalizes most humans is, “Is there other intelligent life out there?” Let’s put some numbers to it—
谈到星系这个话题,令人捉摸不透的问题是,“宇宙中到底有没有其他智慧生命?”让我用数字描述:
As many stars as there are in our galaxy (100 – 400 billion), there are roughly an equal number of galaxies in the observable universe—so for every star in the colossal Milky Way, there’s a whole galaxy out there. All together, that comes out to the typically quoted range of between 1022 and 1024 total stars, which means that for every grain of sand on every beach on Earth, there are 10,000 stars out there.
银河系有多达1000-4000亿颗恒星,这个数量和可观测到的星系一样多,所以对于银河系里的每颗恒星,本系只是一个缩影。所有的恒星加起来,一共有10^22-10^24颗,也就是说地球上每有一粒沙,宇宙中就有10000颗恒星
The science world isn’t in total agreement about what percentage of those stars are “sun-like” (similar in size, temperature, and luminosity)—opinions typically range from 5% to 20%. Going with the most conservative side of that (5%), and the lower end for the number of total stars (1022), gives us 500 quintillion, or 500 billion billion sun-like stars.5^22
科学界没有“类日恒星”统一标准,普遍观点是大小、温度、亮度相差5%到20%。最保守的5%、10^22标准来讲,那就是5^22颗恒星。 |
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