suggested the stars were suns that likely had their own planets and that the universe was infinite. 太阳这样的恒星都有自己的卫星，宇宙是无限的。

　　This idea didn't go over well. 这个理论推广得并不好。

　　Bruno was burned at the stake for his radical suggestion. 布鲁诺因他的激进言论被烧死在刑柱上。

　　Centuries later, the philosopher Rene Descartes proposed that the universe was a series of whirlpools, 几个世纪之后，哲学家勒奈·笛卡尔提出，宇宙是一系列的螺旋体，

　　which he called vortices, and that each star was at the center of a whirlpool. 这些螺旋体被称为漩涡，每个恒星都位于漩涡的中心。

　　In time, we realized there were far more stars than Aristotle ever dreamed. 随着时间的推移， 我们发现星星的数量远多于亚里士多德所能想到的。

　　As astronomers like William Herschel got more and more advanced telescopes, 由于威廉·赫歇尔这样的天文学家发明出了更加先进的望远镜，

　　it became clear that our sun is actually one of many stars inside the Milky Way. 太阳实际是银河系诸多恒星之一这个事实变得清楚。

　　And those smudges we see in the night sky? 那些我们在黑夜里看见的印迹呢？

　　They're other galaxies, just as vast as our Milky Way home. 它们其实是其他星系，它们与我们的母星系银河一样庞大。

　　Maybe we're farther from the center than we ever realized. 我们离宇宙中心的距离可能要比想象中遥远多了。

　　In the 1920s, astronomers studying the nebula wanted to figure out how they were moving. 在20世纪20年代，研究星云的天文学家想弄明白它们的运动规律。

　　Based on the Doppler Effect, they expected to see blue shift for objects moving toward us, 根据多普勒效应，他们预期向我们飞来的物体会呈现蓝移，

　　and red shift for ones moving away. 飞走的物体呈现红移。

　　But all they saw was a red shift. 但所有观测到的现象都是红移。

　　Everything was moving away from us, fast. 所有星星都在快速远离我们。

　　This observation is one of the pieces of evidence for what we now call the Big Bang Theory. 这些观测结果构成了现在被我们称为大爆炸理论的证据。

　　According to this theory, all matter in the universe was once a singular, infinitely dense particle. 根据这一理论，宇宙中的所有物质最初都源于一个密度无限高的单一粒子。

　　In a sense, our piece of the universe was once at the center. 从某种意义上说，我们所在的这部分宇宙曾处在中心。

　　But this theory eliminates the whole idea of a center since there can't be a center to an infinite universe. 但这个理论排除了”宇宙中心”的想法，因为无限宇宙根本没法有中心。

　　The Big Bang wasn't just an explosion in space; it was an explosion of space. 大爆炸并不只是在空间的一次爆炸，而是空间本身的爆炸。

　　What each new discovery proves is that while our observations are limited, 新的发现表明，虽然我们的探索有限，

　　our ability to speculate and dream of what's out there isn't. 但我们探索和幻想更外层宇宙空间的能力是无限的。

　　What we think we know today can change tomorrow. 我们今天所认可的事实有可能很快就被改变。

　　As with many of the thinkers we just met, 和我们刚刚看到的许多思想家一样，

　　sometimes our wildest guesses lead to wonderful and humbling answers 有些时候人类最狂野的想象可以引领我们找到奇妙或屈辱的答案，

　　and propel us toward even more perplexing questions. 并指导我们向更加复杂的问题发出挑战。